We make a mini-crossbow, a crossbow from pencils and from paper with our own hands. How to make a crossbow at home
A crossbow is a throwing weapon that is an improved design of a bow. Its advantage is the ability to aim without unnecessary effort. The technical characteristics of the gun increase the destructive power and shooting accuracy. In our country, the use of this type of throwing weapon is unpopular, since it is difficult to find the necessary design. There is very little inventory, but user interest is quite high. Crossbows are quite expensive. However, the design of the weapon is quite simple, so you can easily make it yourself.
What is a crossbow used for?
First of all, it is worth noting that the use of throwing weapons with a tension force of more than 43 kgf is illegal, whether it is homemade or purchased from official manufacturers. Today, the main uses of the crossbow are sports competitions and outdoor activities.
The device itself was first created two and a half thousand years ago in China. In Europe, the weapon gained popularity only at the beginning of the twelfth century and was used exclusively for military purposes. Later, homemade crossbows were used for hunting. However, only rich people could afford expensive mechanisms and special arrows.
Arrows for this type of weapon are much heavier and are more often called bolts. Their use is necessary since the tension force of the bowstring is much higher and requires the use of heavy projectiles. They, in turn, provide increased power upon impact. Now, the ban on hunting with throwing weapons in Russia and the CIS countries does not allow the use of a crossbow to catch game. Throwing weapons are used exclusively for sporting purposes.
Differences and adaptations
A bow and a crossbow have several obvious differences that must be taken into account when creating a weapon with your own hands. The main differences are:
Tension force. Since the design of the crossbow allows the bowstring to be pulled with greater force, a reliable mechanism is required that does not fail. When purchasing it, you should not skimp, because it guarantees not only safety, but also durability. It is also convenient to use a device for tensioning the bowstring. 
Use of bolts. By adding a spring to hold the projectile, the gun can be used at any desired angle. Aim. Installing additional equipment will ensure accuracy and make it easier to shoot from the shoulder, similar to a firearm.
In addition, when creating a throwing weapon with your own hands, you should pay special attention to the method of tensioning the bowstring. There are several of them. The most reliable and popular are:
Leg or hand braces. A very popular type of tension. However, its use is only available for crossbows with low power. Strap and hook. This method allows you to fix the machine tool with your feet, similar to the first example. When bent, the hook clings to the bowstring, and restoring the position is done by tightening and fixing it. An improved type of the second method is a rope using rollers. The mount is also installed on the belt. The use of two curved arms placed on pins is called a goat leg. The pins protrude on both sides of the stock. The owner pulls the opposite side towards himself, thereby exerting tension. Release lever. The essence of the method is to connect the hook and bracket to the front of the stock. Thus, the bowstring is pressed back. Using rack and pinion gates. A very ancient technology that appeared in the fifteenth century in Germany. The tension is carried out by a collar, which allows the method to be used for very powerful crossbows. Very suitable for hunting because it has killing power.
There are also many other ways to tension the bowstring for certain types of weapons. However, they are used much less frequently and have been used in ancient times. Their safety is significantly lower, which does not guarantee the correct use of weapons. To create a crossbow with your own hands, it is recommended to use one of the above methods.
How to create a throwing weapon
When creating a crossbow with your own hands, it is important to understand that the design must be strong and reliable. Making homemade throwing weapons is not difficult, but it requires a very responsible approach to the work.
First you need to decide on the purpose of using the tool. If it is used for hunting, then special emphasis should be placed on the tension mechanism and stock. If you make the design correctly, then the shooting technique will be much easier to cope with.
After determining the required characteristics, you need to make drawings of the future weapon or find ready-made ones on the Internet. They will not only facilitate the creation process, but also organize the workflow. It is best to use carefully designed drawings with dimensions..
Devices and materials
Before making a throwing weapon for hunting with a small pulling force, you need to organize your workplace and prepare the necessary materials. Here are the main items you will need:
- two meter-long blocks of coniferous wood; a thin strip 6x1 cm; a polyurethane tube with a diameter of 3 cm; nylon fishing line; wheels with a groove in the middle of the edge; screws and nails 5 centimeters long; glue; wooden dowels (6 pieces); tape and foam; vice and rasp; hammer, chisel, saw and drill; pen or pencil.
Also, during the work process, additional materials may be needed to give the tool an aesthetic appearance. However, you can do this at your own discretion. When using a crossbow for hunting, appearance is not so important. However, it can be polished and decorated as desired.
The working process
First of all, you need to make a gun bed. This is the main part to which the rest of the structure is attached. Take one of the prepared bars and apply it to your shoulder to determine a comfortable length. Make a mark with a pencil and saw off the unnecessary part. With your other hand, mark a comfortable position for the trigger. When creating a weapon with your own hands, it is worth considering that the power depends on the length of the stock. The longer the length, the stronger the tension force. For hunting, it is better to use a longer bar. At the location of the trigger, use a chisel and rasp to cut out a rectangle measuring 10x2.5 cm. Across the resulting hole, cut a strip in which the bowstring will be located.
Now you need to cut a groove for the arrow along the beam. Since the work is done with your own hands, it is extremely important to approach this stage responsibly. The accuracy of shooting depends on the correct position. Using a drill and hammer, knock out a 5mm deep groove exactly in the center and sand it.
Cut another block to a length of 60 cm and glue it to the main part of the crossbow. Let the glue dry. After complete fixation, if desired, you can polish the parts. You can do it with your own hands or with special polishing devices.
Now that the main part of the structure is ready, we need to make the shoulders. To do this, use two polymer pipes, each 90 cm long. Make cuts at the ends of one side into which the bowstring will be placed. Their width should correspond to the prepared screws. Insert them into the cuts you made and attach the wheels with the groove.
Take a nylon fishing line. Secure it to one of the screws, then wrap it around each wheel, going from one side to the other. After wrapping it around the wheels, secure the line to another screw with tension. The result should be a curved structure with three rows of strings. When tensioned, the pipes should bend; if this does not happen, repeat the procedure again.
After completing the stage, it is necessary to secure the resulting structure to the main part of the crossbow. To do this, cut a hole at the end of the beam into which the arc will be attached. Insert the pipe into the hollow and wrap it securely with tape. Keep in mind that one string (more taut) should be on top, and the other two on the bottom.
Now you can move on to the trigger mechanism. Take the prepared strip and cut out the letter “L” from it. At the base of the bend, cut a groove so that it is centered and has a width equal to one-third of the full base. Now you need to cut out the part so that it coincides with the hole in the stock. On the side of the bend, drill a hole the thickness of the nail. Place the piece in the hole of the stock and drive a nail into it so that it goes through the drilled hole in the piece.
All that remains is to focus. It will be a sawn-off 20-centimeter block, which must be sanded for convenience. It can be attached to the main part using nails or glue. Wrap the stop with foam and secure with tape.
This completes the creation of a crossbow for hunting. All that remains is to make the arrows. They can be easily made from wooden dowels and trims to the required length. On one side a cut is made for the bowstring, on the other the end is sharpened.
The main thing is not to use the weapon in public places and near places of residence and objects where people may be found. By following safety rules, you can have a great time not only hunting, but also engaging in active recreation.
In this article we will consider the question of how to make a crossbow, using the constructive knowledge of crossbow construction.
To make a reliable crossbow yourself, great hard work and desire are not enough. It is also necessary to have a small knowledge base, material and technical. Of course, you can take a piece of wood and a car spring, and with the tenacity of a maniac, start sharpening, planing, drilling, sawing, focusing approximately on the found images of the crossbow design. But the result may be that the crossbow will be too heavy, inconvenient, and in general the result may not be what you dreamed of and what you wanted.
What to do? First of all, you should determine exactly what kind of crossbow you need to make. After all, there are a large number of types of these throwing weapons and each has its own unusual technical features, which determine completely different techniques for making and using crossbows in practice.
Further, you need to accurately assess your capabilities in terms of equipment, with which you will make crossbow parts with your own hands. And, finally, think carefully about where and what material you need to take to create this or that structure.
Well, let's start by replenishing the knowledge base about crossbows and their types, because without this it is simply impossible to move forward. First, let's look at the general structure of this weapon.
In most cases, any crossbow has the following mechanisms and parts:
- Crossbow guides and stock;
- Shoulders and bow;
- Trigger;
- Tension device;
- Arrows (bolts);
- Bowstring.
Now we need to touch a little on the classification of crossbows. All of them are classified according to certain criteria.
Classification according to shoulder tension level:
- Tension level up to 20 kg. Such crossbows are often used for entertainment and recreation; of course, they are not suitable for any serious tests. The targeted shooting range is not very long (approximately 15-20 meters);
- Tension level 20-55 kg. Such crossbows allow the trigger mechanism to be cocked using muscular force, without any devices. Their sighting range is approximately 60-80 m;
- Tension level is more than 55 kg. Such crossbows are serious weapons that require special cocking devices to tension the bowstring.
Classification according to the type of onion used:
- Monolook. It can be homogeneous, made of steel or fiberglass, or composite using specific types of wood;
- Shoulders + pad. To secure the arms of the bow in this case, a block is used - an intermediate device. Such a crossbow is quite convenient for transportation, because easily understood.
Classification according to the type of shoulders used:
- Block - with the use of rollers and eccentrics, as well as having a main and 2 additional bowstrings;
- Straight - the shoulders in a non-bent position form a straight segment;
- Traditional - S-shaped beam type of bend.
Classification according to the crossbow stock used:
- A traditional screw-type stock with a solid butt, neck and fore-end;
- Stocks of the old type, which are made following the example of medieval crossbows;
- Sports stock with a slot in the butt and a pistol grip.
Classification by tension method:
- Muscular type of tension - has a system of levers, a stirrup, a special hook;
- A goat leg is a single-arm lever;
- Gate - the device has a worm gear and a rack;
- Block tension with multiple rollers.
Now that you have some idea about the design of crossbows, it's time to decide which design is right for you, taking into account your technical capabilities. In other words, make sure you have the ability to use wood and metalworking machines. It is worth believing that with only a drill, a plane and a hacksaw, you are unlikely to be able to make a high-quality crossbow with your own hands. Many parts can only be made by an experienced turner. Even if you have detailed drawings of a crossbow on hand, you will have to use maximum creativity, effort and ingenuity to do everything technically competent and beautiful.
How to make a crossbow for your physical needs. options
Let's start making a crossbow with our own hands from the stock. First, let's take suitable wood. We need a type of wood that will not chip, warp, and will be sufficiently tough. The following species fully meet these parameters: walnut, birch, ash, beech. Undoubtedly, such a tree can be found in any hardware store in our country, so no problems arise.
For a stock, a board 30 cm thick is quite suitable as a starting material (it is not recommended to take more than that - there is simply no need for it). Now you need to decide on the size of the bed. The figure below shows how to choose its size to suit your own physical parameters.
Where:
A– these are your basic physical dimensions:
L– Distance from the bend of the elbow to the end of the index finger;
B2– width of the chest;
H3– distance from the pupil to the collarbone.
B– bed dimensions:
Lп– the length of the stock, which is measured from the front segment of the trigger to the heel of the butt (about 5-15 mm longer than half the back of the butt);
Lps– length from half the back of the butt to the trigger (distance L);
Lн– the length is false from the toe of the butt to the trigger (+/- 15 mm shorter or longer than the distance to half the back of the butt);
A– the distance in front of the butt from the bend of the stock to the bottom;
O– the distance from the heel of the butt to the bend of the stock to the bottom (dimensions “a” and “o” are made depending on the H3 indicators).
IN– retraction of the bed and change to the side, which depends on the width of the chest (B2):
Op– the distance from the heel of the butt to the outlet of the stock;
He– the distance from the toe part of the butt to the outlet of the stock.
The stock must be measured from the beginning of the trigger to various points that are located on the back of the butt. To adjust the bed to the size of your body, you need to use the picture above. But the average sizes are:
From the heel to the beginning of the trigger – 36-36.5 cm;
From the hook to the butt toe the distance is 36.8-37.2 cm;
To the midpoint, which is located on the occipital plane – 35.6-36 cm, “a” – 4-4.5 cm, “b” – 5.5-6 cm.
| Arm length cm |
Stock length up to middle of the back of the head butt, cm |
Pupil height above collarbone, cm |
Vertical bend from the extension of the aiming line to the upper ridge of the butt, mm |
Chest Width between axillary depressions, cm |
Lateral deviation of the butt from the vertical aiming strip, mm | ||
| at the neck | at the back of the head | in the heel of the butt of the head | in the toe of the butt of the head | ||||
| 42 | 38-40 | 23 | 42-44 | 66-70 | 50-52 | 18 | 6 |
| 41 | 37-39 | 22 | 41-43 | 65-69 | 48-49 | 17 | 5.6 |
| 40 | 36-38 | 21 | 40-41 | 64-68 | 46-47 | 16 | 5 |
| 39 | 35-37 | 20 | 39-40 | 63-65 | 44-45 | 15 | 45 |
| 38 | 34-36 | 19 | 37-38 | 60-62 | 42-43 | 14 | 4 |
| 37 | 33-35 | 18 | 35-36 | 58-59 | 40-41 | 12 | 35 |
| 36 | 32-34 | 17 | 34-35 | 57-58 | 38-39 | 10 | 3 |
| 35 | 31-33 | 16 | 33-34 | 56-57 | 36-37 | 8 | 2.5 |
| 34 | 30-32 | 15 | 32-33 | 55-56 | 34-35 | 6 | 2 |
| 33 | 29-31 | 14 | 31-32 | 53-54 | 32-33 | 4 | 15 |
By taking measurements of your body, focusing on this table, you can choose the optimal sizes for your bed, which will suit you almost perfectly. Difficult? It’s not scary, as they say - “It’s hard to learn, it’s easy to fight.”
After which you can proceed directly to making the bed itself. To begin with, it is recommended to cut out a template from paper. On it we draw a bed according to the dimensions that were measured and determined using a table. Sketches of different crossbow stocks are available on the Internet.
We will tell you how to make a crossbow stock, shoulders and trigger mechanism step by step in other articles. In this case, our task is to determine the dimensions of the crossbow parts we need and the materials from which they will be made.
Now let's see where to start creating the crossbow's shoulders. And we start, as usual, by choosing the material from which the shoulders will be made. It seems to me that many people immediately determine what kind of crossbow will be made: with a monobow or with a compound bow.
The material for creating the shoulders should be as follows:
- If you have a sports bow at your disposal, you can use the shoulders from it. You can go to some sports section where you can get decommissioned bows completely free - they will still be thrown away. They, however, can be used for weak crossbows, with a tension of up to 20 kg;
- Fiberglass or textolite is sold in regular construction stores. The tension force is also low - up to 20 kg. Typically used to create crossbows for recreational purposes;
- Car spring - look in your garage, in your neighbor's and in a junkyard. In principle, finding her would not be a problem - if only there was a desire;
- Carbon fiber, fiberglass, various composite materials - again, we go to construction stores.
Any store has similar materials, and at fairly affordable prices.
The highest quality crossbow arms are made from composite materials and fiberglass. Below is a drawing showing the dimensions of their fiberglass arms with a tensile force of up to 40 kg.
To create a monobow, you can use a car spring. The string is attached to it using wheels or pulled onto a trident.
Size chart for monobow drawings.
| Tension force, kg | Working stroke of the bowstring, mm | Dimensions, mm | Width, mm | Thickness, D, mm | Weight, kg | |||
| A | B | C | (in the center) | (at the ends) | ||||
| 60 | 145 | 545 | 70 | 25 | 25 | 8 | 4 | 0.58 |
| 75 | 160 | 572 | 75 | 25 | 25 | 8 | 5 | 0.68 |
| 100 | 160 | 572 | 75 | 25 | 25 | 10 | 6 | 0.85 |
| 120 | 180 | 675 | 70 | 25 | 30 | 10 | 5 | 1.00 |
| 120 | 180 | 660 | 90 | 35 | 30 | 10 | 5 | 1.00 |
| 120 | 180 | 690 | 100 | 35 | 30 | 10 | 5 | 1.10 |
| 280 | 180 | 680 | 100 | 35 | 30 | 12 | 6 | 1.35 |
| 325 | 180 | 675 | 100 | 50 | 40 | 12 | 9 | 1.95 |
With your permission, now it’s time to finish the review of the sizes that you can use to create a crossbow with your own hands. In the following articles we will look in detail at what triggers can be used for a crossbow. We will also look at the drawings of trigger mechanisms that are common in crossbow manufacturing today.
Based on materials from the site: sekach.ru
Evgenia Smirnova
To send light into the depths of the human heart - this is the purpose of the artist
Content
How to make a crossbow - this question worries both hunters and shooting enthusiasts. Shooting from a crossbow, as from a military weapon, is left far behind. Today, crossbow shooting is practiced mainly by professional athletes, as well as by amateurs who want to shoot at targets. Shooting with a crossbow has a number of advantages over shooting with a firearm. Firstly, it is silent shooting, and secondly, accessibility and comparative safety. A crossbow does not require any permission or medical examination to purchase it. You just need to buy a ready-made one (for which you will have to pay several hundred dollars or more), or make a weapon yourself. That is why your favorite useful advice site will tell you today how to make a crossbow yourself.
How to make a mini crossbow - instructions
Types of weapons and ammunition for them
Experts distinguish two types of crossbows - field and match. Ammunition for both types is considered to be feathered arrows. Carbon and duralumin feathered arrows are available on sale. You can learn and compete in shooting using a standard five-color archery target, which is also available for sale. Field crossbow shooters usually compete at distances of 35, 50, 65 meters (outdoors) and 10, 18 meters (indoors). Match shooters usually compete only in special premises - shooting ranges at distances of 10 and 30 meters.
Hunting with a crossbow is an activity for real men
Many owners use their devices for hunting. Hunting with a crossbow is fundamentally different from hunting with a gun - shooting animals from a tower, a helicopter, or driving an animal in a large crowd is not everyone’s cup of tea. Hunting, on the contrary, loves silence and solitude. In some ways, this type of hunting is reminiscent of the famous heroic pastime - hunting a bear with a spear. In fact, to shoot you need to approach the animal at a distance of 50 meters or closer. Not everyone will be able to approach a boar at such a short distance, and approaching it at such a short distance requires special hunting skills. Well, the more valuable the loot!
How to choose
Power
For hunting birds or small animals, a crossbow with a draw power of 50 kg is sufficient. With a pulling power of 50-70 kg, you can hunt large ungulates. For wild boar hunting, crossbows with a power of 80 kg are used.
What ammunition can be used
Hunting large game requires special ammunition. To hunt large prey you need to use special professional arrows made of fiberglass or carbon. These arrows are strong and light enough to be properly centered to ensure a successful hit. There are also sometimes excellent aluminum arrows on sale. But such ammunition is only suitable for hunting small animals or birds. Manufacturers of arrows provide the possibility of turning hunting ammunition into sports ammunition - to do this, you just need to change the arrow tip. The threaded connection allows this to be done very quickly. A hunting arrow weighs from 30 to 35 grams, the length of such an arrow is from 45 to 50 cm. As a rule, the length of the feather of a hunting arrow is longer than that of a sports arrow, because the arrow needs to stabilize faster in flight to assume a firing position.
Now it has become fashionable to hunt with a bow and crossbow. Although this is prohibited in our country, you can still shoot at targets by practicing this difficult task. You can make a crossbow with your own hands at home for training. After all, good models from well-known companies are very expensive. Or it can be made “for yourself”. It is worth remembering that if the weapon has a tension of more than 20 kg, then it is considered a cold weapon. Therefore, when creating a crossbow, it is worth considering this important nuance.
There are classic models, they look like ancient ones, and their design is simple. There are also modern crossbows, they are called "block" crossbows. Such weapons have a more complex design due to blocks and other innovations that enhance their power. It will be much more difficult to make such a crossbow at home, but the description of this process and the drawings, which will be detailed in the article, will help you with this.
The crossbow has many components:
some modern models have blocks at the ends of the bow.
trigger mechanism;
What to make a crossbow from
The main material from which a crossbow is made is wood. The stock and bow are made from it. The trigger mechanism in powerful samples is machined from iron. And those in which the tension force is less than 20 kg can be made of hard wood, it will withstand it quite well. Spring metal and various composites are also used for bows.
Regular crossbow made of wood
First, let's look at how easy it is to make a crossbow with your own hands, and let's start with its simple shape. This is a standard design for ancient weapons, and it can be used not only for shooting, but also as a spectacular piece of furniture when hung on the wall.
What wood to use
To create a crossbow you need to choose:
All of these rocks are dense enough to withstand the enormous stress that will be placed on the bow and crossbow stock.
Preparation of material
In order for a weapon to fire long and powerfully, its material must be properly dried for a year. Having cut the required trunk or branch, both cuts must be painted over. To do this, you can use any glue, paint or varnish. If you close the cuts in this way, moisture will not be able to quickly leave the workpiece, so the wood will dry more slowly and evenly. This way, internal cracks do not form in the material, and a crossbow made with your own hands at home will serve for a very long time.
After this, the log is placed in a dry place where the sun's rays will not fall on it. It should remain like this for a year. After time, the bark is removed from the workpiece, so it dries for another week. The log is then sawn in half. It sits like that for another week, only after that you can start creating a crossbow.
Tools for making a crossbow
Sandpaper of different grits.
Carpenter's cutter.
Chisel.
Making a bow
On the workpiece, choose the side in which the annual rings of the tree are thinner. This is the north side, the fibers on it are denser than in other parts. This is what we will use when creating a crossbow with our own hands at home. From this part you need to make a bow.
Mark the middle, put about two centimeters on both sides of it, marking the part that will be clamped in the crossbow stock. This will be the thickest part of the onion. They begin to cut the material from it, gradually moving towards the edges. They chip the workpiece gradually on both sides, checking until it begins to bend at least a little.
After this, you need to take a strong rope and make loops at its ends. This will be a test string. It is necessary to check the bow tension. It is very important that his shoulders bend evenly. By putting on an improvised bowstring and drawing the bow, you can see where to remove the material. They are marked and carefully cut with a knife. This must be continued until the product begins to bend evenly on both sides.
Knot processing
Very often there are knots on the material: some are visible immediately, others can open during the processing of the material. What makes them dangerous is that they can cause chips. Therefore, you need to treat such places with a well-sharpened knife. If you don't have confidence or experience, it's better to tinker a little longer and sand them down with sandpaper. You can also use a file for this purpose.
Bed
When the bow is ready, put it aside and begin making the stock. To begin with, they choose where there will be a groove through which the arrow will fly out, and make this place perfectly level. It will depend on him how accurately the crossbow will shoot. To understand everything, it is better to look at the drawing of the crossbow. How to make its stock is shown in detail here. After this, the gutter is cut to the required length. Usually it is about 30 cm. Then a recess is made for the bow and trigger mechanism. They are convenient to cut with a chisel and a carpenter's knife.
Trigger
As mentioned above, it can be made of dense wood or, if the crossbow is powerful, of metal. The most is the so-called “nut”. It consists of a cylinder, where on one side there is a hook for the bowstring, and on the other there is a stop for the trigger. In high-power crossbows, the trigger is more refined for an easier trigger pull when loaded.
We looked at it in detail, the Master class with drawings, we hope, will help you understand all the intricacies.
This is a common medieval model. Now we’ll find out how to make the same weapon, only a modern model.
Compound crossbow
Such a device is much more difficult to make; it will require many more tools than a regular one. So, we create a crossbow with our own hands at home from fiberglass. This material is ideal for making bows because it is tough and yet lightweight. It can be cut from a single piece of fiberglass 1 cm thick or you can make it yourself. If you’re not too lazy to tinker, it’s better to make it yourself.
Making fiberglass shoulders for a crossbow
You need to take fiberglass or Kevlar and cut it into strips. You need from 30 to 40 of them. In general, it is better to try everything experimentally. These strips are glued with epoxy resin so that everything becomes monolithic when it hardens. You also need to think about how to put this entire “sandwich” under the press. It is best to use boards, place the shoulders between them, and clamp everything with clamps.
There should be less thickener than usual, ranging from 8 to 10%. Everything hardens within 24 hours, but if the room is cold, the time may increase. When everything has hardened, the shoulders are finalized by cutting off the protruding edges with a knife and sanding with sandpaper.
Now we will look in detail at how to make a crossbow with your own hands at home and what additional elements of its design need to be made.
Making a figured bed
To do this, you need to take a board at least 4 cm thick. Mark where the butt, handle, trigger mechanism and mounts for the arms of the bow will be. In general, everything is according to the drawings. After this, you need to drill all the necessary holes and cut them out.
Blocks
They can be made from aluminum. It would be better if they were on bearings. The middle parts of roller skate wheels are perfect. They are strong enough to withstand heavy loads and are the perfect size. The axles for them need to be 5 mm thick. You can take them from rollers or make them yourself.
The fasteners are made of sheet steel or similar durable material. You can also make the ends of the bow arms thicker before pouring epoxy resin to install the blocks, in which case fastenings will not be needed.
After this, you need to install a trigger mechanism with a trigger and an arrow holder on the crossbow you made yourself at home. In general, all parts are connected with bolts; washers are always used. They will allow you to twist everything more tightly without damaging the material.
In compound crossbows, the bowstring is longer and is tensioned differently. It seems to cross, and when drawn, this system allows the arrow to give twice as much energy to flight as in the case of a conventional crossbow with the same bow.
In powerful block models, the bowstring is the only one capable of withstanding the enormous sharp pressure of a shot. In crossbows whose power is no more than 40-50 kg, it can be woven from nylon threads.
Making a bowstring for a crossbow
Using the described method, you can make a bowstring for both a recurve and a classic crossbow. It’s just that their length will be different due to the design features of both models.
They take a board the length of the planned bowstring, drive in two pegs, on which they are wound in a circle. When the thickness of this long oval becomes 5 mm, it is wound, making a gap of 2-3 mm between the turns. Near the pegs you need to braid without gaps, because there will be loops for hooking.
Regarding the bowstring, one can also say that if you make it too thick, the strength of the crossbow is reduced. However, thin ones can tear. So in this case you need to choose an intermediate thickness. It is better to study similar sports models with the same tension and make a bowstring of their thickness. When this is done, the two halves are joined and wrapped together. Again, special care is needed near the hinges. Then they wrap the middle where the string will catch and push the arrow. This place is also done carefully, because it will be subject to a tremendous frictional force. All cut edges of the threads must be coated with glue. This will make them denser and more monolithic.
This article presents drawings and a description of how to make a real crossbow at home. It's not that difficult, especially if you're making wooden weapons. If the product is manufactured for hunting in order to achieve enormous power, then you should choose a block model. Its design is a little more complicated; you may need a machine to make some parts.
MODERN CROSSBOWS - BASICS, TERMINOLOGY, CLASSIFICATION
Part 1
The popularity of this weapon is growing, more and more people want to touch this wonderful example of human progress. After all, humanity has always strived to hit targets faster, more accurately, and from a greater distance. Some people want to touch their childhood dream, some hunt, some want to make a crossbow with their own hands, and some just like to shoot at a target. Most newcomers to the crossbow business have many questions about which crossbow to buy or make, what a “block”, “guide”, “shako”, “cable” is, how a “block” differs from a “classic” and many other questions.
Indeed, the former powerful throwing weapon of ancient armies is experiencing a kind of “Renaissance” in our time, now it is available to almost everyone. Any citizen who has reached the age of 18 and has a passport can purchase a crossbow with an arc force of up to 43 kg, which has an appropriate certificate. Naturally, there are also restrictions - in our country, crossbows with a tension force of over 43 kg are considered weapons, and hunting with them is prohibited. That is, even if you have a hunting license, it’s not your destiny to hunt with a crossbow. Perhaps, after some time, something in this regard will change in our legislation, and the hunter will be able to feel what it is like to be one on one with a powerful beast, when one arrow is loaded and there is no room for error, since reloading a crossbow, even with a cocking lever, takes quite a long time. Naturally, the hunter with a crossbow bears more responsibility, since there is no opportunity to fire a second shot and finish off the wounded animal. The shot must be fired from a short distance and certainly in an area incompatible with the life of the animal.
The point of this article is not to tell where and how the crossbow (crossbow) came from, but to explain what parts a crossbow consists of, what types of crossbows there are, what accessories are used for them, types of ammunition, tensioning devices, etc.
1. Main parts of the crossbow and basic terms
A modern crossbow, of course, in its operating principle (the release of a projectile being thrown by a bowstring held by a trigger mechanism, through a trigger lever (hook), due to the stored energy of an elastic element (arc, shoulders) located across the bed) is no different from its older brother, however The design has undergone quite significant changes.
First, let's look at the main parts of the crossbow using the example of a device with the so-called “classical” layout (Fig. 1). The most noticeable difference between it and the usual old crossbow design will be the presence of separate arms instead of a solid arc. But since the vast majority of modern crossbows have such separate arms, they are actually the “classics” of our time.
Fig.1. Main parts of a crossbow.
Fig.2. Crossbow with a single guide stock
All parts of the crossbow are mounted on a single profile - a guide. There are crossbows in which all the parts are attached directly to the stock and there is no such part as such. In this case, the guide is the groove in which the arrow is placed. An example of such a crossbow is shown in Fig. 2. Please note - the crossbow shown in the last picture also has simpler - straight shoulders. The guide should not have any bends or curvature, because in essence it is the “barrel” of the crossbow. You yourself understand what shooting from a weapon with a crooked muzzle will be like. The guide, in the part along which the bowstring and arrow will move, is polished for better sliding of the projectile and less wear on the winding of the bowstring. Also, additionally use lubricant. The bowstring is rubbed with wax (beeswax or special wax for bowstrings).
As mentioned above, in most modern crossbows the arc is split, that is, in fact we have two separate arms. Firstly, it allows the arms to be raised so that they are level with the top edge of the guide without tilting, which reduces friction between the string and the guide; secondly, it allows the shoulders to be positioned more parallel to the guide; and thirdly, for ease of transportation. It is very important that both shoulders have the same characteristics in terms of geometric parameters and physical properties.
The arms are attached to the guide or directly to the stock using a block - this part, which carries a serious load, is subject to fairly stringent requirements for strength and geometry. After all, the synchronization of the work of the shoulders will depend on the accuracy of its manufacture, and the reliability and health of the shooter will depend on its strength. In general, in a crossbow, for proper operation and accurate shooting, the accuracy of the manufacturing of the mechanisms must be at a fairly high level.
Fig.3. Crossbow-pistol with a separate superstructure over the castle
The bowstring is an important and very important part of the crossbow. It must meet several requirements - be strong, light, flexible, not stretch, and hold a tug well. Mostly, modern crossbows have a bowstring made of synthetic fiber Dyneema. Fishing braid is also made from the same fibers, which, due to its wide selection and availability, is one of the best materials for weaving a bowstring yourself. On the bowstring, in places of friction against the guide and on the loops thrown over the ends of the arms, a winding is made, for example, from nylon thread. Such a winding is rewound as it wears out - this mainly concerns the warhead, where the bowstring wears out the most.
A trigger mechanism (SM), which is also called a lock, is mounted in the rear part of the guide. This mechanism keeps the bowstring cocked and allows it to be easily released when the trigger (lever) is pulled. It can be assembled directly into the guide or have a separate housing mounted into it. If the guide, as a separate part, is missing, then the lock cuts directly into the stock. The body of an SM crossbow in the upper part usually has a superstructure on which sighting devices or rails, such as a dovetail, Weaver or Picatinny rail, are mounted, for all kinds of optical or collimator sights. Also attached to the superstructure is an arrow clamp, which is a leaf spring that keeps the arrow from falling out in a loaded crossbow. On some crossbows, the superstructure is not part of the lock, but is attached as a separate part to the crossbow above the SM (Fig. 3). There are add-ons that can be adjusted - they change the angle of inclination, which makes it possible to adapt the crossbow sights to longer distances, because the flight of an arrow in terms of flatness (straightness) is much inferior to that of a firearm. Although, in my humble opinion, this does not make much sense, since the speed of the arrow drops quite strongly with distance, and the time it takes for it to fly, for example, 200 m, is quite long. Naturally, the lethality at such a distance is low.
Fig.4. Assembling the main parts of the crossbow
A little about the crossbow stock. In principle, there are no big differences from firearm stocks. The only thing is, due to the superstructure and highly raised sights, the butt line is located higher. The guide assembly with the remaining parts of the crossbow is attached to the stock or, as mentioned above, all parts of the crossbow are mounted on the stock itself. An example of assembling the main parts of a crossbow is shown in Fig. 4.
2. Classification of crossbows
According to state standards of the Russian Federation [Change No. 1 GOST R 51905-2002 Sports crossbows, crossbows for recreation and entertainment and shells for them. Technical requirements and safety test methods], crossbows are usually divided into:
universal sport-hunting and match crossbows, which are throwing weapons and intended for use in sport hunting, in the educational and training process and during competitions;
sports crossbows (traditional, field, etc.), not related to throwing weapons, which are sports equipment intended for use in the educational and training process and during competitions;
crossbows for recreation and entertainment, not related to throwing weapons, which are household products intended for leisure and mass sports;
homemade crossbows (in terms of determining whether they belong to throwing weapons during forensic examinations).
The main criterion for gradation is the strength of the crossbow's arcs (Table 1).
Table 1
For the same guest there is the following classification table (Table 2). This is what concerns the legislation and standards of the Russian Federation.
table 2
Fig.5. Sports match crossbow.
But I would like to propose a slightly different classification of modern crossbows.
Classification by purpose:
1. Sports match crossbows
2. Copies, replicas of ancient crossbows
3. Crossbows for fun and recreation
4. Hunting crossbows.
With match crossbows (Fig. 5), in general, everything is clear - this is a separate class of crossbows that are a sports equipment and at the same time, according to the forensic requirements of the Russian Federation, a weapon. We will not dwell on them in detail.
Fig.6. Replica of a medieval crossbow (by "Dirty" Burdwood)
Next, in second class, are copies and replicas of ancient crossbows - military, sporting and hunting crossbows manufactured before the 20th century. That is, these are Greek gastraphetes, and arquebuses (a crossbow with a barrel), and schnappers with balestres (crossbows that fire bullets), as well as classic crossbows, with cocking devices improved over the centuries - with a belt hook, with a “goat leg”, with an English collar, with a cranekin. Naturally, according to the same forensic requirements, most copies, especially authentic ones, will be weapons. But replicas of ancient crossbows have only external similarities with the originals, and even then, often the external differences are so significant that only to a person completely inexperienced in crossbows, such products may seem like a copy (Fig. 6). Materials for manufacturing can be any, including a variety of polymers. Such crossbows may well fit within the legal limits of 43 kg. Copies and replicas of ancient crossbows are mainly souvenirs and museum products, as well as the path of fans and re-enactors of these weapons. Although, there are quite a large number of crossbow unions abroad that specialize specifically in antique crossbows and hold meetings, exhibitions and shooting competitions. But still, such crossbows are not suitable for recreational shooting, especially for spears, due to their power (again the notorious “43 kg”), the complexity of manufacturing ammunition (the shape of ancient bolts is mostly spindle-shaped), which often simply shatter into splinters upon impact o target.
Let me make a comparison: being interested in antique crossbows is akin to smoking a pipe. This is a manifestation of a certain aestheticism, listen to how such people speak about their hobby: “...to get pleasure from smoking a pipe, it takes time. This is a cigarette you can smoke while running, at work, in the toilet. Pipe is a ritual. Choose an hour or two, relax. Let the bustle leave you for a while. Slowly and carefully hammer in the tube. Relax comfortably in your favorite chair. Light it lovingly and take a mouthful of aromatic smoke. Release a puff of smoke and feel how all your problems dissolve in it. Your hand is warmed by a gentle and devoted friend, and in her beauty, in the convolutions of wood patterns and smooth lines, you will discover something new for yourself every time. Such beauty and devotion in women is sometimes more difficult to find than in pipes...” ( http://voffka.com/archives/2006/09/19/029976.html).
Let's move on to the so-called crossbows for entertainment and recreation. The majority of crossbows on the market are of this class. This includes pistol crossbows and rifle crossbows of all designs not exceeding a peak cocking force of 43 kg. Many crossbows in this group are from the following class - the hunting class, but with weakened shoulders by the standards of our country. Although with 43-kilogram shoulders, this is especially true for block crossbows, due to their design features, you can hunt small game and birds. For example, one of the record holders for arrow speed, Bowtech “Desert Stryker” (Fig. 7), was equipped for the Russian Federation with weakened arms of 43 kg.
Fig.7. Bowtech "Desert Stryker"
There are no serious design differences in hunting crossbows. The main thing is their powerful shoulders - up to 80 kg in block crossbows and up to 150 or more in classic crossbows. This allows you to send a heavy arrow with a broadhead tip (three or four bladed hunting tip) to the target with good energy. Naturally, hunting crossbows are always the most expensive and most well-equipped devices.
Classification according to the design of the power section.
1. Crossbows with classic shoulders:
a) with simple shoulders;
b) with recursive arms.
2. Block crossbows:
a) with a pulley system of 2, 4, 6 and 8 rollers;
b) with round eccentric blocks;
c) with oval eccentric blocks;
d) with binary eccentrics.
3. Crossbows with non-classical shoulder placement:
a) with reverse shoulders;
b) with a different arrangement of arms and a system of rollers (blocks).
Let's look at the above structures in order. Simple shoulders in a free state without a bowstring are a straight or slightly curved plate towards the shooter (mono-bow) or a pair of such plates (split shoulders). Most ancient crossbows had a monobow, but in modern crossbows split shoulders have become more common. An example of simple separate shoulders is a model from the Canadian company “Excalibur” for the teenage generation (Fig.. Also, such shoulders are not uncommon among home-made people due to the availability of material (springs from cars, as well as other spring elements - saws, torsion bars) and ease of manufacture An example of the author’s homemade product with shoulders made from a circular saw blade is shown in Fig. 2.
Fig.8. Crossbow Excalibur "Apex Light"
The majority of modern crossbows of the “classical” layout are equipped with recurve arms. Such shoulders differ from straight ones in that they have a characteristic and quite noticeable bend forward at the ends. In a free state, without a bowstring, the ends of such arms, as a rule, go forward further than the line of the bowstring and even further than the middle of the bow, forming an arc curved away from the shooter (Fig. 10). The degree of recursiveness can vary widely. Almost all crossbows produced by the same company “Excalibur” have such shoulders (Fig. 9, 10).
Rice. 9. Excalibur “Equinox” crossbow with recurve arms.
Rice. 10. Excalibur “VIXEN” crossbow front with arms without string.
Recursive shoulders can also be mono (Fig. 11) or split.
Fig. 11. Barnett "Commando" crossbow with a recurve mono arc.
Both simple and recursive shoulders are made with a narrowing from the root to the ends. Often both in width and thickness. This is done so that the shoulders bend when tensioned evenly along the entire length, or even a little more towards the ends, which helps to increase the efficiency of the shoulders - the weight decreases, the speed of straightening the shoulders increases.
Recursiveness helps achieve even greater efficiency. The curved ends of the arms provide additional leverage, which, as the bowstring is pulled, seems to increase the length of the arm, changing the distance from the center of rotation (from the center of the bow) to the bowstring. That is, as the resistance of the arc increases, the leverage by which we overcome this resistance also increases . Thanks to this, the recurve bow draws more evenly, its force changes less throughout the entire working stroke, and with the same tension as a regular (simple) bow, the recurve bow has a much greater preload*, which gives it the opportunity to push the arrow with greater force to the very end. In fact, there is a partial change in the “gear ratio” of the arc force to the string.
(*A bow with a bowstring installed, but in an uncocked state, is pre-tensioned, that is, it has a preload. The amount of preload is selected in such a way that the material from which the arms are made has a margin of safety for the required working stroke of the bowstring. That is, a compromise is found between the power of the arc and the properties of the material from which it is made. In simple words, we shorten the bowstring - we increase the preload, accordingly the power of the bow changes to a greater extent, but the chance of its breakage also increases with the ensuing consequences of possible injury to the shooter.)
The next stage in the development of crossbows was systems with a pulley system. The pulley is a clip with one or more round movable rollers (Fig. 12). In theory, depending on the multiplicity (the number of cable branches and the number of rollers) of the pulley, it is possible to reduce the tension force of the bowstring from two to four times (systems with two, four, six, eight rollers) and increase the speed of movement of the bowstring when shooting at the same number of times.
Fig. 12. The principle of operation of the block and pulley. a – single block (with one cable stretched along the groove of a single pulley); b – a combination of two single blocks with a single cable covering both pulleys; c – a pair of double-groove blocks, through four paired grooves of which a single cable passes.
Also, a system with a pulley system allows you to reduce the transverse dimensions of the crossbow, since the stroke of the end of the arm in them is significantly less with the usual length of the working stroke. In practice, in addition to the advantages, there are also disadvantages of this system: losses due to friction of the cable on the rollers, friction of their axes, movement of the mass of the shoulder shackles (earrings are the roller clips at the end of the arms), non-parallelism of the cable branches (strings, which in pulley systems significant).
In Fig. 13 shows an example of how by adding a pair of rollers and the same stroke of the ends of the arms, the stroke of the bowstring increases.
Fig. 13. Comparison of a pulley system with simple arms.
Most factory-designed pulley crossbows have eight rollers (Fig. 14). Crossbows with two rollers are extremely rare (Fig. 15), as well as with six – I can only cite as an example the wonderful homemade “Lynx” crossbow from Zmeelink (Fig. 16). There are many homemade devices with four rollers (Fig. 17), and there are also factory ones (Fig. 1.
Fig. 14. Crossbow Interloper "Black Python".
Fig. 15. Crossbow from Ralph's
On factory and many homemade crossbows, the middle rollers are connected to the next pair by a rod, as in Fig. 14, 17, 18, but practice has shown that it is better to make them rigidly fixed to the guide, which allows them to be lowered below the level of the rollers at the ends of the arms without interfering with the free movement of the bowstring and the straightening of the shoulders (Fig. 16, 19).
Rice. 16. Crossbow “Lynx” from Zmeelink
Rice. 17. Crossbow from daf13
Rice. 18. Crossbow-pistol Interloper “Aspid”.
Rice. 19. Crossbow with eight rollers, the middle ones are rigidly fixed
For optimal operation of pulley systems, the arms, relative to the guide, should be located as parallel to it as possible, since the bowstring acts on the ends of the arms through rollers, which tend to bend the arms not towards the shooter, but towards each other. That is, the sharper the angle between the shoulder and the guide, the better. Of course, if the shoulders are placed parallel, this will significantly reduce the transverse dimensions of the crossbow, but will also increase the longitudinal ones. Therefore, here it is worth looking for the “golden mean” - and the shoulders are rarely placed at an angle less than 45 degrees to the guide. A good solution was suggested by http://forum.arbalet.info/viewtopic.php?t=2802&postdays=0&postorder=asc&start=960 igora - pseudoparallel shoulders (Fig. 19).
Rice. 19. Pseudoparallel shoulders, by igora
As the author himself described it: “The essence of the proposed 2nd method is to make the shoulders of an ordinary one-piece monobow work just as parallel to the stock (which is what all manufacturers strive for) while remaining a regular arc and even without bending at all. At the same time, the gear ratio of the chain hoist used increases. Moreover, for example, in the figure, the chain hoist in the 2nd version will give a gear ratio approximately like that of an 8-roller, but in reality only two of them are added. Well (and most importantly!) the direction of the forces applied to the shoulder will be corrected). The biggest problem I see is the long string, but not longer than the 8-roller.”
The shoulders of pulley crossbows are made short and rigid, often without narrowing in width and thickness, because the stroke of the end of the shoulder in these systems is small, and the force that the shoulders must create is several times higher than in “classical” systems. The material of the factory shoulders is unidirectional fiberglass. Homemade, most often - springs from cars,
The pulley transfers force from the shoulders to the string through a certain gear ratio (which usually reduces the force and increases the stroke). But since this gear ratio is constant, then as the bending increases, the force on the arc increases in the same way on the bowstring. To get rid of this, and to further improve the shooting qualities of crossbows, so-called blocks appeared. They allow you to transfer force from the shoulders to the bowstring with a variable gear ratio, thereby ensuring that, regardless of the degree of bending of the arc and the force on it, the desired force is always on the bowstring. Some of the simplest blocks are round eccentric blocks. This is a more complex system compared to a pulley system - each block consists of two rollers secured together, the axis on which it rotates is offset from the center (Fig. 20). There are two bowstrings - one of two parts, connecting the power rollers of the blocks and the opposite ends of the arms, is called a power or technical bowstring (blue with a yellow fork in the figure), and the second is a combat or high-speed bowstring, which directly accelerates the arrow (white with a red winding, Fig. 21).
Fig.20. Round eccentric blocks (the hole for the axle is highlighted)
Rice. 21. System with round eccentric blocks
The layout and reeving of bowstrings in systems with round eccentric blocks is shown in Fig. 22. Also, the ends of the power strings can be attached not to the rollers at the ends of the block axes (Fig. 21), but by means of a transition piece under the block, attached to the axle (Fig. 23).
Due to the fact that the power string does not extend much lower than the speed string, it became necessary to lower it somewhat so that it does not interfere with the lower feathering of the arrow. Therefore, all crossbows with eccentrics have a characteristic slot for a power bowstring, with a guide part running inside it along with two slots for the left and right power bowstrings (Fig. 22).
Fig.22a. Location of blocks, string and pressing part (top view)
Fig.22b. Location of blocks, string and pressing part (bottom view)
Another feature of the eccentrics is that at the end of the tension, the operation of the block provides the so-called reset - a sharp decrease in the tension force. Therefore, in such crossbows, the tension force is measured by the peak force, and not by bringing the bowstring to the lock, as with simple and recursive arcs or in pulley systems.
Rice. 23. Barnett “Lightning” crossbow with round eccentrics.
The next stage in the development of crossbows was the use of oval eccentrics instead of round blocks (Fig. 24). The shape of these blocks only resembles an oval, but in fact it is more complex. The fact is that in such blocks, the force on the bowstring is controlled not only by simply shifting the axis of the block, but also by changing the very shape of the rollers that form the block. This allows you to create absolutely any desired force on the bowstring throughout its entire working stroke. A small illustration of the operation of an oval eccentric (Fig. 25 (by Andrey 74)) shows how the gear ratio between the power and speed parts of the block changes during its unwinding.
By combining the shapes and sizes of the power and speed parts of the block, as well as their relationship with each other, you can select the optimal characteristics of force, speed and stroke of the bowstring for specific shoulders. Examples of crossbows with oval eccentrics in Fig. 26, 27, 28.
Rice. 24. Oval eccentric blocks
Rice. 25. Illustration of the operation of an oval eccentric (author andrey 74)
Fig.26. Ten Point "Phantom"
Rice. 27. Darton “Serpent”
Rice. 28. Crossbow Parker “SAFARI CLASSIC”
On some models of crossbows with oval eccentrics, the blocks are installed in the opposite direction and the bowstring lies on the side opposite to the shooter - these are the so-called “mirror blocks” (Fig. 29). In this case, the crossbow becomes somewhat more compact in the longitudinal direction than with the usual arrangement of eccentrics.
Rice. 29. Parker “Cyclone” crossbow
Recently, there has been a tendency to increase blocks almost to the size of archers. By winding more string from the blocks, we get a larger stroke of the string, which means that the transverse dimensions of crossbows can be further reduced. Despite the fact that with such large eccentrics, the stroke of the crossbow string approached 45 cm! The most striking representatives of the new generation of crossbows and record holders for arrow speed are the PSE “TAC-15” (Fig. 30) and Bowtech “Stryker” (Fig. 32) crossbows. Both crossbows are unique in their own way.
Let's take a closer look at the TAC-15. Due to its huge eccentrics, the width from axis to axis of the blocks in the uncocked state is 42.5 cm, and in the cocked state - 29.8 cm. And the stroke of the bowstring is a record for a crossbow - 45 cm! With a peak force of 77.2 kg, it is capable of sending a 425 grain (26.44 g) arrow at a speed of 125.6 m/s. At this time, this is an absolute record for crossbows. The kinetic energy developed in this case is up to 217 J, sufficient for hunting any large animal. The crossbow is also unusual in that the back of the crossbow is from an AR-15 (M16) automatic rifle - as you know, this rifle has a modular design (Fig. 31). Therefore, any weapon based on the M16 can be easily converted into a crossbow. The TAC-15 has a built-in winch-type cocking device. One more point - the arrow of this crossbow does not lie on the guide, but, like a bow, rests with its leading edge on the shelf. And the arrows recommended by the manufacturer also have a record length for crossbows - 26.25 inches (~66.7 cm)!
Rice. 30. Crossbow PSE “TAC-15”.
Rice. 31. AR-15 rifle
Rice. 32. Crossbow Bowtech "Stryker"
The Bowtech "Stryker" crossbow has slightly more modest characteristics, it launches an arrow weighing 425 grains at a speed of 123.4 m/s, while having a kinetic energy of 210 J. Its width from the axis to the axis of the block in the untensioned state is 69.2 cm, and when stretched it is 61.6 cm, the peak tension force is 79.45 kg with a bowstring stroke of 432 mm. But the Stryker has one feature - binary eccentrics, which classifies it as the next subclass of compound crossbows.
What are the differences between binary eccentrics and ordinary oval ones? Let's try to figure it out. All compound crossbows have one bad feature - the center of their bowstring (arrow stop) can shift to the left or right due to the fact that each one rotates independently, as a result of which shooting accuracy decreases. In binary systems, on the blocks there is an additional third pulley, on which the other end of the power string of the right or left side is wound, due to which synchronization occurs (Fig. 33. (author igora)). In Fig. 34 shows an example of a binary eccentric of a compound bow for clarity.
Rice. 33. Illustration of the operation of binary eccentrics from igora
Rice. 34. Binary eccentric compound bow
Even the brilliant Leonardo da Vinci came up with a design for crossbows with reverse arms (Fig. 35), and only recently did crossbows of this design begin to be mass-produced. The first sign was the Armcross "LeoPro" crossbow, created by Russian designers (Fig. 36). The main advantages of such crossbows are: compactness (reduced longitudinal and transverse dimensions), better weight distribution, reduced shot recoil, because when shooting, the shoulders do not move away from the shooter, but as if to each other and a little “into the shoulder.” In Fig. 37 you can see how compact the LeoPro is. Among the disadvantages of a crossbow, we can highlight the sharp angle of tension of the bowstring (Fig. 3, due to which it is convenient to cock the crossbow only using a cocking device, and also, purely hypothetically, it can be assumed that the shoulders, which are too close to the shooter’s face, can break injure.
Rice. 35. Schemes by Leonardo da Vinci
Rice. 36. Crossbow Armcross "LeoPro"
Rice. 37. Crossbow Armcross "LeoPro" with a specially designed unloading vest
Rice. 38. Cocking the Armcross "LeoPro" crossbow using a tensioner (shown below to the right)
Rice. 39. Crossbow Horton “Recon 175”
Another crossbow with reverse arms is produced by the Horton company - “Recon 175” (Fig. 39). Please note that both of the most famous crossbows with reverse arms have round eccentrics, which does not prevent them from showing very good characteristics - the initial arrow speed reaches 99 m/s.
It is not advisable to make such crossbows with a classical layout, that is, without blocks, since the shoulders will “run away” in the direction opposite to the tension and the efficiency, relative to crossbows with a classically located arc, will be much lower.
Recently, another player has appeared in the camp of crossbows with reverse arms - “Scorpyd” (Fig. 40). According to new trends, its blocks are binary and large in size. The stated initial speed of the arrow is 425 feet per second, which corresponds to 129.5 m/s! The stroke of the bowstring of this compact crossbow reaches a record 52 cm!
Rice. 40. Crossbow “Scorpyd” SLP
Among homemade products there are also crossbows of a similar design. Almost all have a similar “LeoPro” design, but mostly with a pulley system with two or four rollers (Fig. 41, 42, 43).
Fig.41. Crossbow from OLEKS
Fig.42. Crossbow from sa1982
Rice. 43. Crossbow from Frank
So, it’s time to touch on the last type of crossbow with a non-classical arrangement of shoulders - this is a crossbow that was released by the Swiss company Swiss Crossbow Makers - “Twinbow II” (Fig. 44). This crossbow is unusual not only in the location and operation of the shoulders, but also in its unique cocking device (Fig. 45). With compact dimensions (length 875 mm, width 420 mm) and a bowstring stroke of only 197 mm, it has very good power - with a tension of 180 kg, arrow speed of up to 113 m/s and energy of 145 J! When the bowstring is tensioned, the arms become almost parallel; both ends of each arm work through a roller system. As a result, the recoil when shooting from such a powerful crossbow is practically not felt.
Fig.44. Crossbow “Twinbow II”
Fig.45. Cocking the Twinbow II crossbow
There are several homemade crossbows made according to the “Twinbow II” design. The gunsmith111 crossbow (Fig. 46) uses a twin system without a cocking lever. But on shushai crossbows the main feature of the Swiss is implemented - cocking with a lever (Fig. 47 and 4.
Rice. 46. Crossbow from gunsmith111
Rice. 47. Crossbow “Twilight” from shushai
Rice. 48. Crossbow “Cyclone” from shushai
PART 2
3. Triggers of modern crossbows.
As mentioned above, the trigger mechanism (lock) of a crossbow can be an integral part of the design of the guide (stock) or can be mounted in a separate housing. The latter are found much more often both among crossbow manufacturers and home-made people, due to the convenience of installing a ready-made trigger mechanism (SM) in any place.
With all the variety of modern crossbow triggers, locks can be divided into three main types:
a) with a lower hook (nut, cracker) (Fig. 49a);
b) with an upper hook (Fig. 49b).
c) with a fixed hook (pin lock) (Fig. 49c)
A) 
b)
Rice. 49. Triggers with lower (a) and upper (b) hook
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