Do-it-yourself trigger mechanism for a crossbow. Making a crossbow

What do we need:
- paper;
- ruler;
- pen;
- steel corner 4 mm thick;
- Bulgarian;
- steel plate 2-3 mm thick;
- vice;
- file;
- drill;
- bolts and nuts;
- springs.

First of all, you need to draw on a piece of paper the details that will later be cut out of steel. For greater convenience, we bring drawings of all the details that can be easily redrawn or simply printed on a printer. During the manufacture, a steel plate will be used, which can be removed from the old door lock.

Next, take a piece of steel corner and cut it in half with a grinder.

We transfer the drawings of our blanks to the resulting pieces of steel.

We cut out blanks and drill holes in places that can also be seen in the figures below.

Next, take the steel plate from the door lock. From this plate, you need to cut two blanks, the drawing of which is presented.
Now we clamp two workpieces from the plate into a vise and carefully process it with a file, twisting sharp corners to avoid future injuries.

We put the blanks on the plates as shown in the figure.

At this stage, you need to drill holes on the plates so that when you press the trigger, the part on the left is released, on which the bowstring will be worn. The author advises not to immediately drill holes on the plate, but to experiment on similar plywood blanks. During the experiment of the mechanism on plywood plates, it will be possible to find out exactly whether the structure works correctly. Note that not only your safety, but also the safety of others depends on the assembly of the trigger mechanism.

After the locations of the future holes are known, we temporarily glue the steel plates with superglue and transfer the hole marks to them. Superglue can be removed by dropping the plates into boiling water.

We make holes according to the marks.

We also drill three holes on the sides of the plates.

All blanks are ready, you can proceed to the assembly of the trigger mechanism. Let's start with the side bolts, as well as the trigger bolts, which we thread onto one of the steel plates.

Screw the nuts onto the side bolts. It is important to consider here that the nuts must be of such thickness that the main parts of the trigger mechanism move freely between them.

There are many designs of the crossbow trigger mechanism, we will talk about some. Let's dwell on two options: pin and roller.

Crossbow pin mechanism

The pin mechanism is easy to manufacture. It is easy to do it yourself. How to make a pin mechanism? For the pin mechanism on the bed, you need to work out a groove. A bowstring will be wound through this groove. Directly under the bowstring, a vent is drilled into which either a wooden or metal pin is inserted. At the bottom of the bed, a bar is attached so that when pressed on it, it presses on the pin. The pin, having thus received a command, pushes the bowstring out of the groove. The device is simple, easy to manufacture, but has many drawbacks: there is no fuse in the mechanism, heavy descent, wears out just as quickly.

It is also possible to make a similar design with your own hands.

In order to make a roller trigger, you need to purchase a metal roller. In the video, on the one hand, we make a gash for the bowstring, and on the other hand, under the trigger lever. We insert the roller in the bed, and fasten it with an axis passing through the bed and the center of the roller. The algorithm of the roller mechanism is as follows:

if the string is on the roller, she presses on it.
the other side of the roller rests on the trigger lever, and does not allow it to turn.
pressing on the lever, we allow the roller to turn, and reset the bowstring.

a photo. Trigger

Modern most simple trigger mechanism for crossbows

Crossbow trigger, also called a lock, can be a common design with a guide, or can be mounted in a separate housing. Some are more common.

a photo. Crossbow trigger

All locks are divided into three types:

With a lower hook (nut);
Top hook;
With a fixed hook (pin).

How to make a trigger for a crossbow with your own hands

Here we will outline how to make a trigger. We will show everything on the diagrams and photos.

This photo shows what parts the trigger consists of.

Materials and tools needed in the manufacture of the mechanism:

A piece of stainless steel, 10 * 15 cm in size, 2-3 mm thick. The front leaf of the door lock is perfect.
Three M12 bolts and 6 M12 nuts,
Two M10 bolts and two M10 nuts,
A couple of springs. We draw on paper diagrams of the trigger and hook, in full size

We cut out the patterns, and transfer the dimensions to the stainless steel.

Now we cut out the parts from stainless steel, and carefully process them from burrs.

Now we draw a diagram of the side parts of the mechanism.

We also transfer it to metal, and cut it out. We clean the burrs with a file.

Before drilling holes, make a plywood layout. Check if it works fine, transfer to blanks. Make holes in the metal. Install the parts, fix the springs. Assemble the side plates. The trigger mechanism is ready.

A few tips:

Axes for the trigger must be made of high-quality steel and with a diameter of 6 millimeters. You can use screwdrivers, drill shanks.

As a material for parts, you can use: springs, large hexagons, turning tools and other steel products. Walnut can be collected from several layers, and then they are riveted.

The side walls of the lock can be made of sheet steel or aluminum alloys. For ordinary crossbows, the thickness of the metal can be from 3 mm, and for massive crossbows from 3 mm. Aluminum from 4 mm, for all crossbows.

If it is not possible or you do not know how to draw mechanisms in electronic CAD packages, you should draw your trigger mechanism on graph paper in natural size. Then cut out the components from cardboard and pin the place of the axles with pins, all the details in their original condition - and take a look at how your mechanism will work.

Crossbow trigger drawing, cocked

The crossbow is one of the inventions that changed history. Prior to its invention, an archer needed to train for many years before becoming an effective warrior. With a crossbow, even the average peasant could be a soldier. In addition, by using a cocking mechanism, cross force is no longer a limiting factor.

Here is my instruction on how to make a wooden crossbow with photos and drawings.

Be careful because the crossbow can kill or injure you, your dog, etc.

Step 1: Crossbow Bow

All you need is to decide on the size.

The overall length is 125 cm with a width of 6.5 cm in the center, tapering to 1.25 cm at the edges. The thickness is 1.1 cm.

I made the fasteners for the bowstring from hardwood pins.

I also covered the arc with denim. I just put a piece of jeans and soaked it in glue, rolled it out with a rolling pin.

Step 2: Crossbow Stock

The stock was modeled in ProE. In fact, these are two rectangles - one 7.5 x 50 cm 14 x 37 cm, the other 14 x 37 cm.

Take the measurements from the picture and cut two pieces out of 2cm plywood (I used plywood because I had it on hand).

Once the two parts are ready, they are connected to each other with wood screws because they will need to be taken apart several times.

Now it will be useful to use a planer to align the top edges of the two pieces. If you don't have a planer (I didn't), screw the stock to the board and level the edges with a saw. The top edges must be flat and even.

Step 3: Trigger

Break the box into two parts.
Work on the inside of one of the pieces.
Measure 50 cm from the longest part, and then go down 5 mm. This will be the center of the circle. Using a compass, draw a circle with a diameter of 4 cm.

Draw a line from the bottom of the 6mm circle, then drop this line down to the end of the stock. Make an orthogonal line from the end of the line inside the circle to the end of the stock.

Inside this area will be your trigger. You can see in the picture where I sketched out the lines to mark the hole.

The hole is the pivot point for the hook.

Step 4: Trigger Continuation

Here I used a wood router to cut the wood 6mm deep. Subsequently, I put a sheet of paper on the cutout and made a contour to transfer this cutout to the second part of the box. At this point, it is important to drill a hole in the center of the circle, as your marks will be inside after assembly.

Step 5: Assembling the Crossbow Stock

Glue and screw the two parts of the stock together, being careful not to get glue on the trigger. Attach a 0.5 cm piece of hard wood to the top of the stock, I used maple. After the glue has dried, use a hole saw to make a 4cm hole where the trigger will be.

Then use a grinder or sandpaper to remove the burrs.

Step 6: Nut

The nut will hold the string when the crossbow is cocked. It must be strong and strong. I made a nut out of red oak plywood and glued the layers together with epoxy. Honestly, five layers is not enough, and here you can try better.

In any case, once the stock of the crossbow has dried, you need to insert the nut into the hole.

The width of the nut should be the same as the width of the stock.

The bottom half of the nut is cut off to make the trigger. The top half is cut in half to make notches that will hold the bowstring. An additional incision is also made so that the arrow can come into contact with the bowstring.

The nut will be held in place with blocks on both sides.

Step 7: Trigger

You need to take a sheet of paper on which you marked the cutout on the bed. This will help determine where the trigger will sit.

The top edge of the trigger should be straight. Just make the hook strong enough and small enough to support the weight of the crossbow and make the nut spin.

I used a piece of hardwood plywood. This is a bad choice as it crumbles. To fix this, I reinforced the piece with a carpet nail.

Once you've made the trigger the same as in the photo, finish drilling the pivot hole and make sure the hook can rotate.

Step 8: Attaching the Crossbow Bow

To make it easier to attach, I use a bolt that goes through the bow into the stock and secure with a nut hidden in the cross.

Step 9: String

I made a hemp string with 16 strands 122 cm long. This is not a very good string, but for the first time it will do.

Step 10: Conclusion

A wooden crossbow made with your own hands is ready, what remains to be done?

Since it's plywood, I'll probably paint the crossbow.
There are no security mechanisms.
Front sight to shoot straight.
Make an arrow holder, if you tilt the crossbow, the arrow will fall out.
The thread needs to be done better.
Various fasteners.
I measured the kinetic energy. The shot gives an energy of 28 J, which is below the recommended minimum of 33 J for hunting, so you need to make a stronger crossbow.

Archery training. The archery section of our website contains information about almost all well-known archery clubs and sections in Moscow and Russia. If you have information about the existence of a section (club) that is not in the list, you can add it. Choose the right place for archery. In most sections, archery classes for children are free. Recruitment of children and adults to the section usually takes place at the beginning of the school year (September), but most coaches continue to accept newcomers throughout the year. In sports schools, as a rule, beginners are given a bow for beginners, arrows and the necessary equipment. In extreme cases, you can buy a bow for shooting in numerous online stores selling bows, crossbows and related products. The cost of a bow for a beginner is about 3 thousand rubles. Join. Just one word of warning: Archery is a very addictive sport, it can drag on, and for a long time ;-)

NEWS section in the world of archery. This section constantly publishes news taking place in shooting sports, the opening of new sections or clubs, competitions, archery tournaments, changes in competition rules, interviews with coaches and archery athletes and much more. You can publish your announcement (article, news) about an upcoming (or past) competition, tournament, or other event. Please indicate the coordinates of the organizers, the date, place, etc.

A must read!

Making homemade weapons, in particular crossbows and bows, less often knives, are usually engaged in teenagers and young people up to twenty, twenty-three years old. Older people prefer buy factory-made branded weapons. However, there are exceptions.

For example, an older person may be fascinated self-made weapons at the level of hobby and collecting. But more often than not, his passion for becoming closer to professional work, as it is not a one-time impulse. According to statistics, this site is visited mainly by young people from fourteen to twenty-eight years old (according to Yandex metrics). They are mainly interested methods and methods of making any homemade weapon.

However, with an unprofessional attitude to the subject of interest and a lack of technical skills, the creation of homemade products can lead to undesirable traumatic situations that can harm the health and even, in some cases, the life of young experimenters. Therefore, if you are on fire with the idea, by all means purchase one of types of permitted weapons, then it is better to buy it in a store, or contact a qualified specialist. Of course, in this case, certain costs will be required, but they are not as critical as it seems at first glance. That is, your health is much more expensive than a certain amount of money spent on buying, for example, a crossbow.

Naturally, not all young people have available funds for the purchase of weapons, and not everyone has the right to use it, even if it belongs to the category of sports, due to their age. Therefore, in specialized stores it can only be sold to a person who has reached the age of majority and has an appropriate document authorizing the purchase and use of weapons for personal purposes.

Otherwise, the case with online gun shops, for which it does not matter to whom weapons are sent, and all surveys during registration have a formal look. But as mentioned above, adolescents under the age of eighteen rarely have their own income and therefore in most cases sporting weapon is acquired with the knowledge of the parents and with their direct participation.

More for fans of ready-made stock drawings

Please note that the crossbow is made “from the bow”. That is, what kind of bow is, the crossbow will be adjusted to its parameters, because each bow has its own unique parameters - the pulling force, the length of the pull, the length of the shoulders, finally. Further, the castle also meets the given requests, it has its own geometry and it may not always be suitable for the desired type of box. So there is no point in such drawings and they can only be considered as an illustration for understanding the general principle of the layout of parts.

Some features of the manufacture of stocks for crossbows deserve closer attention, allowing you to save material and nerves. When making a stock for a compound bow, please note that the groove in it for the intersecting sections of the bowstring must be extended towards the lock, since when pulled, the ends of the bow with blocks are bent back. Sometimes an incorrect cut causes a radical change in the location of the nodes, which entails a change in the design of the product as a whole, sometimes not for the better. Do not forget to leave at least a millimeter in reserve. By milling, you can only set the initial shape, for example, of the lock groove, and finally finish it with the help of a small chisel and files with needle files.

A small note about the final processing of stocks

The question is often asked about where to get the drawings of the stock, the stock can be made even from the leg of a chair, but the crossbow itself, in the end, should not be just a designer of ridiculous details, but should be a product made in the same style. For example, crossbows in the style of the Middle Ages with a powerful bow, forged fittings, a rigid lock and a rough wooden stock look holistically and balanced; or a light and elegant sports crossbow with optics, a thin and biting bow, an anatomical stock; not to mention the futuristic crossbows with polished metal surfaces, laser pointer, titanium-cast stock and super complex lock. In other words, the final finish depends on your taste, but remember that it will be judged by your crossbow.

More about guides

High-quality guides are the most important element that affects the accuracy of shooting, as they set the initial orientation of the bolt (arrow). They can be made from any material, desirably having a low coefficient of friction. Although the guides receive almost no load, they must have sufficient strength to maintain straightness. Therefore, it is not bad to make them as a separate part, attached to the stock at points at its ends. This makes it possible, if necessary, to easily change it, for example, in case of damage or switching to another type of bolts, moreover, such fasteners allow you to “untie” the guides from the deformable stock. The longitudinal guide groove for the bolt is usually one-third the diameter of the shaft so that the plane of the bowstring coincides with the axis of the bolt. It is convenient when a narrow groove for the lower plumage passes through the guide, then random needles when shooting in the forest, for example, will not interfere with the bolt stroke.

As already mentioned, it is convenient to make guides separately from the stock. The material can be metal, plastic or wood. The necessary thin longitudinal groove can be made with a thin hacksaw blade of an electric jigsaw or by making a guide from two halves, which is also very convenient and has its advantages. A particularly important factor in the manufacture is the observance of absolute straightness and parallelism. Naturally, you will have to apply sandpaper or a polishing hairy circle. The dimensions are not critical at all and are determined only by the length of the stock section from the block to the lock, corresponding to the running (landing) part of the bolt, as well as the diameter of the bolt shaft and the type of its plumage. The bolt should lie freely, but without backlash, in the guide groove, the plumage should not touch anything. The guides are installed in such a way that the axis of the inserted bolt coincides in the front with the fastening of the bowstring (! nuance) on the bow, and in the back, passes through the filling cutout of the lock. The nuance lies in the fact that it is precisely the front part of the guide that should be slightly higher than the indicated plane, which ensures some sliding of the bowstring pushing the bolt. Naturally, everything should be within reasonable limits, and the wooden surface of the guide must be protected from abrasion by the bowstring with additional metal plates.

Lock

A lock made of clothespins and tin can hardly deserve any attention. The crossbow lock is a very important detail. There is an opinion that the simpler the lock, the more reliable it is, but I would interpret it a little differently - the better the lock, the more reliable it is. The manufacture of the lock should be treated with special attention, because convenience and reliability, as well as the accuracy of operation, and hence the accuracy of shooting, depend on its operation. A little about the functions of the castle. A good lock should provide a guaranteed retention of the bowstring on an equipped crossbow, as well as a clear descent at the required moment of aiming. It is in accordance with the first paragraph that additional interlocks and fuses are introduced into the design of the locks, and with the second - intermediate unloading levers and repeaters. The choice of lock design again depends on your locksmith capabilities and needs, and here you can freely show your creative inclinations to modernize existing samples and develop your own. Personally, I liked the design of professional locks presented on one of the sites. The bicycle has been invented, but has it been invented yet?

To make it easier to embed the lock, it is necessary, even when designing it, to try to give it the simplest possible shape. That is, locks with various depressions are unlikely to be neatly packed into the stock, while at the same time, flat, rectangular locks in this regard do not cause any special problems when cutting into the stock. It is important to take into account that the locks must be securely fastened, without backlash, have a maximum contact area with the stock to relieve the load. Often overlooked is the simple fact that the lock bears the entire tension load. That is, if you are making a crossbow with a bow of 300 kg (probably for an elephant), then, of course, all 300 kg + impact load and so on will come from them to the details of the castle, but the stock should manage in its thinnest place (usually where it is weakened by the keyway), survive the same 300 kg + twisting and other non-parallel loads. Again, in some drawings, the locks have attachment points too close to the edges or small diameter holes for thin bolts or screws. If for metal this value is acceptable, then for wood it is necessary to provide for some margin. So, summing up all the factors, we can conclude that the lock should have a minimum size, in particular, a width, have a maximum contact surface with the groove, that is, fit snugly with its front surface in the groove, and only be fixed with bolts on the stock. In addition, the stock itself must have sufficient strength in its weakest part in order to calculate the bow tension load. So for monsters, it’s better to make a stock from a metal profile, and put linings from beautiful durable wood on the body kit. To the extent of my incompetence on this issue, I cannot give special recommendations regarding the choice of wood, although I personally prefer beech.

For those who do not live in the regions where this wonderful tree grows, I advise you to pay close attention to the old pianos of your acquaintances and friends. In them, beech is found in the form of massive power beams for hanging frame cast iron. At the risk of angering the aesthetes, a piano is easier to find these days than a piece of good wood. Let's write off this barbarism as a by-product of art. For metal lovers. Excellent aluminum and alloy profiles can be found in office furniture. Rigid rectangular profiles are now ubiquitous in some machine tools. A wonderful thin-walled pipe made of blackened metal is in .... large inclined tablet like designers or draftsmen. I don’t know what the warriors have to do with it, but such a pipe can also be used in powerful pneumatic and light firearms systems, as well as for mortars for fireworks. You can also cast stocks from aluminum and alloys, followed by milling grooves and other things, but this is more a matter of technology and taste.

Let me remind you that the bow tension force acts on the lock! This means that the lock must withstand the impact of large loads without loss of performance, so that tin as a material is immediately excluded. The proposed mm steel, after processing already 0.8 mm, can only be used on crossbows of small power, otherwise the lock will simply deform. The details of the castle are also worth a closer look. The main hook works under full load, so use stronger steel and a thicker axle. On the release, releasing the hook, depending on the design and the lever, a smaller force acts. Other parts can be made already on the basis of their purpose and the load on them, while not forgetting about the margin of safety and wear resistance. Gunsmith designers have a technology for designing the mechanisms of real weapon locks “on pins and needles”, this is when the contours of the alleged parts of the lock are cut out of cardboard, pinned with pins at the points of their axes to plywood. At the same time, it is possible to immediately see the interaction of parts with each other, correct, and then embody everything in metal. In principle, it remains only to choose a suitable lock, further modernization can be achieved by using high-quality steel, some modification of the escapement and equipping the lock with additional devices, adjustments, etc.

Structurally, locks with a so-called “nut” or a similar hook design are more suitable for crossbow sniping. The hook rotates freely on an axis close to the center of mass, which results in a very soft, jerk-free descent. Such locks will appeal to fans of high-precision shooting and the fairer sex (there are also such people in this business!), But aggressive locks clanging and clattering like Hollywood will be more useful in systems of a menacing militaristic or medieval style of execution. In one of the “pro” locks, the design of which I took as the basis for my own, there is a safety lock and a blocker that excludes the lowering of the bowstring without a tucked bolt, which is quite thoughtful for preserving the bowstring. By adding a slot in the upper part of the hook, it was possible to ensure the impact-free interaction of the bowstring on the knock, the rear end of the bolt, in the common people “butt”.

Block

Designed for fastening the bow or its limbs directly to the stock. The block works in a very stressful mode, experiences shock loads, therefore it must have a significant margin of safety. It is made of aluminum casting or metal, calculated depending on the bow used. The block for separate limbs of the bow is affected by more forces with different vectors. When designing pads, it is necessary to correctly use various slopes and triangles, which can significantly save in weight with the same rigidity of the part. The block can be removable to reduce the dimensions of the crossbow when carried. There is a certain peculiarity in the way of fastening the limbs to the stock, which is that it is preferable to use fastening on threaded clamps than on rivets, but it is better not to weaken the limbs with holes at all. (!) Pay special attention to the fastening of the bow arms, take into account the rule of leverage, which, coupled with the pulling force of the bow, adds up to an immodest amount. It is most convenient to make a block from thick sheet steel, bending the workpiece like origami.

The bow is the main part of any crossbow.

Structurally, it is easier to use a mono bow made of strong and elastic steel, however, some plastics are also applicable. The simplest thing is to use ready-made bows for shooting sports. Can be made from any elastic spring steel, such as springs. We used a powerful spring from some kind of relic hell trap. A stacked bow, consisting of a pack of stripes, has huge friction losses between the stripes. Even if you lubricate the strips with something like "ER" to reduce friction, the use of such a bow is not practical. If you want to make a detachable bow with snaps, then I advise you to fasten the bow to the block tightly, but the block itself can be made tightly fastened to the stock. In general, analyzing the physics of the bow, it can be noted that a bow with developed shoulders, which have some narrowing towards the ends, is better. Such a bow, evenly bending, accumulates a lot of energy. However, longbows require a longer stock due to the increased draw travel, which is unacceptable. Ancient crossbows, judging by the sources, hit 200 paces. So it was they who “beat”, knocking riders off their horses, and for a longer firing range, perfect sights are already needed, and even now no one shoots from machine guns at a greater range, it makes no sense. We’ll talk more about firing range in the paragraph on bolts.

If possible, then you can forge a bow from a suitable metal, and it is better to immediately provide for the fastening points of the bowstring on the block. Again, making a block diagram is better if the bow has a lot of power.

The brackets of the blocks, the blocks themselves work on the bow tension force + bowstring compression force + shock loads. Blocks can be machined from a material of suitable strength, however, it is necessary to unload the shoulders of the bow as much as possible. In most cases, the choice of aluminum as block material is very successful. For those who have difficulty making blocks, I recommend looking into old reel-to-reel tape recorders. In some models, there are wonderful blanks for aluminum alloy blocks, you just need to cut off the excess. To facilitate the blocks, holes are drilled in them or windows are cut out. You can also look into old receivers, where the vanier is based on a cable system. The warriors have a lot of old radio equipment with such blocks. There are small blocks on ancient dental burstans. On professional crossbows, the blocks are oval. This is due to the fact that the block rotates only a small angle. I think that the fact of some gain when using the block scheme versus the usual, recursive one is obvious, but a further increase in the number of blocks gives less and less result. So it makes no sense to collect a garland of 6,8,10 blocks. A four-block crossbow is capable of pulling even a child. I note that a compound bow works softer than a recursive one, which improves the accuracy of shooting, besides, the force to break the bowstring on it is less, apparently due to the loading of the bowstring with blocks.

Springs are sometimes used as a propellant on some exotic models, but they have a lot of weight, volume, low speed and huge energy, which in turn entails a complication of the design and requires high-quality steel for locks. A compressed automobile damper spring can easily tear off a person's arm or leg. A shot with such a spring into a bag with caked cement pierced it, and the spring itself flew away behind a row of neighboring garages. Very dangerous and inconvenient thing.

Bolt - an arrow for a crossbow

The bolt is the striking element of this type of weapon. It has a greater (emphasis on the first syllable) stopping effect than a bullet (!). Kevlar vests also lose their effectiveness against such a hello from the Middle Ages. So it would be appropriate to once again remind you of the observance of safety rules when shooting from a crossbow, despite the fact that the article is devoted to a slightly different topic. A bolt wound can often be fatal! The lethal outcome of the victim can be caused even just by the sight of a bolt sticking out of the body!

So bolts. They are made of any durable material with low weight and sufficient elasticity. Can be made from suitable blanks of straight-grained wood, with the layers of wood arranged lengthwise to give the arrow flexibility. It is difficult to do without small-scale mechanization in the form of at least an electric drill. The bolt must have a perfect shape, the center of gravity is usually between the first and second third of the bolt, and already assembled (!), However, it is possible to vary this parameter at your discretion. You can change the mass of the bolt by choosing different material for the shaft, the dimensions and material of the tips and socks. To protect against moisture, wooden shafts of bolts are impregnated with protective compounds and are usually stored in a horizontal position. Wonderful bolts can be made from sections of broken fiberglass telescopic rods. They have great strength with low weight and are not afraid of dampness. I draw your attention to the fact that all bolts should be as close as possible in weight and size, otherwise with each new shot you will be in for a surprise, especially when shooting at maximum range. In general, the crossbow itself allows you to shoot quite heavy arrows, even with welding electrodes, so it is rather difficult to clearly determine the optimal bolt. When choosing by experience a lot of bolts for your crossbow, do not forget about the golden mean: a light bolt loses speed faster, and a heavy bolt does not fly far. Instructions for self-made bolts -.

About firing range

Crossbow, there is a crossbow. The bolt, like an arrow, is launched with a relatively low initial speed, has a sufficiently large air resistance and a small mass, so that purely physically it cannot fly very far, one must be realistic. There are firearms for such things. By the way, looking back into antiquity, the crossbow was valued precisely because it was used exclusively for the extermination of heavy cavalry at medium distances, having a short and heavy arrow in its arsenal. Articles that mention shooting for almost a kilometer, I consider purely humorous.

Bolt tips are made based on the task for this type. Hunting bolts are generally equipped with creepy-looking four- or three-blade harpoon-like tips. For sports shooting, almost any solid material is applicable. When shooting at hard targets, bolts often break. It is better to make tips with a recess for mounting on the shaft of the bolt. Tips attached to the pole cut will usually split the pole when it hits a hard obstacle. Rubber tips don't make sense. The diameter of the tip may exceed the diameter of the bolt if the shaft is longer than the guide.

bowstring

A good bowstring with proper care will last a long time. It is made of steel (cables, strings), polymer wood or woven from silk. I don’t know about the latter, now there is a huge amount of synthetic materials. Kevlar for the manufacture of bowstrings should go as a material with high tensile strength. For powerful crossbows, you can use a thin steel cable for the bowstring. It is found everywhere in motorcycle and automotive equipment. I note that a braided bowstring more easily tolerates breaking loads due to the fact that part of the energy is spent on friction between the braided threads. Protect the bowstring from abrasion against the stock with special overlays made of metal or plastic.

Sights

Actually, it's a matter of your taste. The use of certain sights depends on the range and nature of the crossbow shooting. Optical sights for weapons at a hundred meters or less are generally somehow ridiculous, although a crossbow with optics looks pretty predatory. They have a large mass and exorbitant cost, require a standard mounting bar, and are convenient for firing at a static target. The installation of collimator sights in this case is more justified, in addition, it becomes possible to shoot offhand. Simple diopter sights are even simpler and better for crossbows, and the simplest open sight is not difficult to make at all. I’ll keep silent about optics for now, but you can stop at the manufacture of open or diopter sights. The fact is that there is some difference between the axis of the bolt flight and the axis of the crossbow, not to mention the hinged trajectory of the arrow flight, so for sights it is necessary to provide for the possibility of fine tuning using the appropriate screws. To do this, the mount of sights is made with oval holes that allow some displacement, or adjusting screws with fine threads are installed in the body of the mounts, which displace the sight itself during rotation. Sighting of sights is best done indoors or in calm weather. In this case, the crossbow itself is fixed on a massive fixed base, for example, with clamps. Next, trial shots are made with one reference arrow. The difference between the aiming point and the actual point of impact of the bolt at a given distance is corrected by the adjusting screws of the sight. Then the shooting distance changes and the process repeats. Thus, any sight can be calibrated for any shooting distance. Similarly, corrections for the wind are made (frontal against the wind, at an angle towards, at an angle downwind, sideways, downwind).

Tensioners such as various "goat legs" are easy to make from a suitable metal by resizing the data to fit the geometry of your own crossbow, however, such devices are rather necessary for cocking very powerful crossbows with recurve bows or are simply a convenient overkill, since compound bows are even a fair amount of power can be cocked by hand, albeit with gloves.

This completes the theoretical part of the instructions on how to make a crossbow, see the photo and explanations below:

To make a crossbow we need a wooden stick and a piece of iron

The stick is made approximately according to these dimensions.

One spring plate 650X100X8 was taken. Bulgarian slowly separate the right. The dimensions of the arch in the middle - 35 mm., And along the edges - 18 mm.

On the emery we narrow the shoulders, evenly from the center to the ends until we reach 5 mm. in thickness. On the arch in this form we stretch (cable) steel wire. We clamp it in a vice. We will insert a round timber strictly in the center so that it does not interfere with the arch when bending. We stretch and at the same time check the force and distance of the tension. From these parameters we will dance in the future.

As in the "Golden Calf": we take a weight and saw. And that's what happened. The most important detail in a crossbow. Toe or cat.

But in order to make a normal lock, we need a sear and a trigger. A hole is made in the upper part of the pin so that the bolt of the strip spring falls into this hole and fixes the pin from moving.

Let's start making the lock case

We carefully try on all this and drill holes for the pins

We proceed to the manufacture of the protection of the trigger. We take a wooden stick and try it on.

Hollow out a place under the castle

We insert the lock

To attach the rear sight we make a dovetail. And solder. I did it with PSR, but you can also use POS. It all depends on how we burn (what temperature it will be).

In the arch, we drill two holes at the edges for fastening the clamps. Many people ask if it is possible to drill a spring. I answer freely. A Pobedite drill adjusted on a diamond wheel.

We grind rollers

We grind rollers

We adjust the clamps to the desired size. We proceed to the manufacture of the arch mounting clamp.

Making a stirrup

This is how I close the ends of the bowstring. Do not beat, but crimp with a lathe chuck.

Under construction and finished look

Ready view

We proceed to a very serious operation - bluing. I specially show unsuccessful bluing.

And here is a successful bluing

We take a stick and make a channel for the guide

Glue the plank

Now we take up the butt, but carefully with the tools

We remove the excess. The stick I took is a wild cherry. Suitable for birch, walnut, etc.

Varnishing. But then who gives preference to what varnish.

Excess. But, in my opinion, pleasing to the eye.

It is important that the gap between the bowstring and the bed is 2 mm. The calculation is simple - the middle of the bolt diameter.

Bottom view

And he pulled a shrink film over the arch. And it gives the appearance and protects in case of breakage of the arch from splinters.

Ready view

After 40-50 shots, the string broke.

I decided to add 2 more videos.

To facilitate the design, the rollers were replaced with caprolon ones. With a distance of 30 cm from the string to the hook and a force of 85 kg. with the addition of rollers, the force on the arch is reduced and the boom speed is increased.