Cheap easy crossbow build yielding effective hunting weapon

Hi guys, I have been gone awhile on travel but I am home now and back to crossbow stuff and still on my mission to develop and produce low cost drop in triggers to aid the DIY Xbow builders. Especially the first time builders who may not have a shop full tools at their disposal.
So I thought I would post my latest build with with some ideas on how someone can build a fun crossbow suitable for hunting and target shooting without investing in a ton of tools and material. Keep mind that I am no expert like some on this site. So use what is useful and toss the rest!  
To me the first design consideration is the bow. The rest of the design flows around it. Weight of course, but most important is draw length.
So here are some bow options that I know. First, the crossbow store (online- google it) can  supply ready made bows (prods). I have used Barnett 150 lb prods from that site and they worked very well. They come with a string and ship already strung for $65. I have tested them on my bow testing rack and they pull a true 150 LB at 17" of draw. They shoot 22" 460 grain arrows at and average speed of 223 FPS. (51 Foot LB of energy) Not super speed for a crossbow but way faster than any of my homemade recurve hand bows and those recurves shot completely through deer, pigs, and elk over the years. So I am sure it will take any kind of game. They also have lower cost ($29.95) Chinese bows but they don't have a string and I have heard that they are actually much lower poundage than the advertised 150 lb, like 120# or so, but I have never used one myself.
There are many other options, including steel bows made from car springs and ready made crossbows prods provided by artisans talked about on this site.
But back to the CHEAP option. This bow is based on ideas posted by KenH on this site. (Thanks Ken!) The bow shown below cost me a whole $10! Now that is my kind of price !

As Ken described in his post it is made of fiberglass fence tensioner rod material and is a loose stack design. I found a local supplier here in Orlando and picked up a 8 foot section for $10.  I wanted to have the same draw length as the Barnett bows (17") so I made the outer leaf 35" and the nocks are 34" apart. The other three leafs are 28", 18", and 10". I wrapped the center with strong cord and also added short wraps at each section as seen below. For the nocks, I epoxied on a short piece of walnut about a quarter inch thick at the tip and tapering down to about 1/8. I filed and sanded the shapes and then added deep nocks for the main string and a shllow inboard nock for the bastard string as seen here:



This bow came in at 145 Lb at the 17" and gives an arrow speed with the same heavy 460 grain arrow of 208 FPS. (44 Foot Lb of energy) The difference from the Barnett being due I suspect mainly to the increased efficiency of the Barnett recurve design and the slightly lower draw weight on this one.
The disadvantages of this bow are, 1) Width - Barnett is 28" tip to tip strung and this one is 32" tip to tip for the same draw length. 2) Slightly lower speed. (208 FPS ver 223 FPS) 3) You have to make the string.
Advantages: 1) Fun of making your own. 2) CHEAP! 3) Having something different than the crowd.

And here is the finished (OK near finished) cheap Xbow;



Well this is getting long winded and I have only covered bow ideas so far so I will stop here for now and follow up with cheap easy stock and trigger thoughts soon.
John

Couple of points I for got to mention about the bow tip overlays. First, very important, you must sand off the finish down to raw fiberglass prior to gluing the wooden tip overlays. Second, use HIGH Strength epoxy, not the 5 minute stuff. I made mine about 2" long to insure enough surface area for the glue. I have build several this way and never had one come off.

Geezer here to say your cheap and easy crossbow looks very nice, and in fact 208 fps is not at all unreasonable.  If you had used a steel 150 lb. prod you'd have got about the same.  There should be enough power there for target practice out to 50-60 yards and you should be able to take game with no problem.  Be proud of your work, it looks just fine.

Thanks Geezer!

So now that we know the draw length we can lay out the stock. The classic rifle stock works well or you can let your imagination run wild like I did a bit here, or use one of the  designs from antiquity. Keep in mind that if you are using a bow of a poundage that will be hard to cock by hand, you will want to use a rope cocking device. If so you will need something  behind the trigger block for the rope to hook onto. That is the reason for the notch in the stock behind the lock on this example. I have also used a peg on a rifle style stock.
STOCK
You can actually use about ANY wood that you like. Maple and Walnut are excellent. You can buy a thick block and carve it all out but this is about cheap and easy. So for the cheap part I used pine and for the easy part I will describe the three board method. The only tools required are a scroll saw (band saw - even better), hand drill, chisel, wood rasp, files.  You can get wood and everything required at Home Depot / Lowe's any time.
So one of the hard parts is getting the main groove down the center of the "barrel" straight, uniform, and centered. With this method that comes for free and no router or other special tools required. This project started with a 4 foot 1 X 8 furniture grade pine board (actual width 3/4"), and 4 foot 1/4 X 4 of oak (could be any wood). Make sure the boards are strait. The stock is a glued up sandwich of the 3/4" pine on the outside and the 1/4 board in the center. By aligning the center 1/4 board down a bit from the top of the other two, a 1/4" groove is left automatically. I drop it 5/8" for fletch clearance.
A picture is worth  . . . .so:


I used a template here but it is not required. You can just draw and cut one side and use it as a template for the second side. Below you can see how the center is dropped down to leave the notch.



Another advantage of this method is that you can inlet for the trigger before gluing up, Trust me this is MUCH easier than after! The lock (trigger) I am using here is 1 1/4" wide so I inlet each side 1/2" and completely cut away the center.  Also a some what narrower area below the main trigger case  for the trigger parts that protrude out of the bottom of the case as shown here:



Drill the holes for the through pins now also. these holes can also be used to align the wood during final glue up.




I like to glue the center to one side first. You don't need a full coverage with one 1/4" center board, you can use pieces and parts as long as all the edges are covered. Like this:



Once that is set up, you can align and glue on the other side:




You should end up with something like this:



Note that clamps are VERY useful here but you could just lay it on a flat floor and put heavy weights on top. I like LOTS of clamps!

Now you take your wood rasp and cut away everything that doesn't look like a stock. LOL   It actually is not that hard. Rasp away until you get the shape you like. Then file and sand.
Should look something like this:


Apply finish of your choice. For this cheap project, I used one step wipe on finish (stain and finish together) and applied two coats, steel wool in between.


 Well that is enough for now. Next, my favorite part, Triggers! Then sights and miscellaneous hardware.
Thanks for reading,
John

Coming along nicely. I really like these loose laminate tension bar prods, working on my second one currently. For anyone who might be thinking of using this material I will say this: The painted finish on these bars doesn't like to bend like the fiberglass and may splinter over time, simply wrapping the prod in some hemp or sanding off the painted finish will keep the paint from splintering and tearing out fiberglass on the back.

I can't wait to show off the tension bar build I've got in the works.

Good tip Xamllew, thanks. I haven't had any issues with paint or glass splintering YET but I will try wrapping it if the problem shows up.
Thanks again,
John

Background:
The trigger assembly may be the hardest part of any crossbow build for most folks as most don't have a machine shop at their disposal. And any of the good triggers require some machining. Yes you can use a simple peg pushing the string out of a notch type but the high tension, stiff trigger pull, and high string ware of these types really don't give me a warm feeling. If you like them and they work for you, great. My goals in my designing and experiments were light trigger pull, low string friction, solid lock up, and low a possible ware on the shear surfaces for longevity. My first attempt was a modern overhead claw type. I added a hammer and inertia transfer bar which allowed allowed very nice rifle like trigger pull and the hammer acted as an automatic safety. I posted it here last year. Here is a picture of the first prototype:


The disadvantages are that is a bit heavy, high parts count,  and it requires a lot of machine operate time to produce all the parts.


Not Cheap for sure. I may come back to it some day but it needs more development.
The most common type is of course the nut and tiller used in Europe. I designed a nut and trigger drop in version and we set up a CNC mill to make a run and sold a few on Ebay. It looks like this:



If you want to try to make your own like this or simulator, I posted all the info on this site and I am happy to provide any details that may help. PM me.
They are OK and we may make some more if people want them but I now have a new type that I like WAY better.
It started when I built a direct copy of a Chinese trigger shown here:



If you wonder how the internal parts of a Chinese trigger work, I made this short Youtube video:

https://www.youtube.com/watch?v=RJ7NrZVPdqk

I tried it and man did it work great! Low trigger pull, low shear pressure, and unlike the spinning nut style, it always ends up in the ready to cock position. And it doesn't make that annoying buzzing noise that the spinning nut makes.  Very, very nice to shoot. And it is low parts count. (Cheap! ) But there is a problem. You can't shoot modern 3 fletched arrows out of it.   The "down" fletch that rides in the groove of the stock, hits the case. So you have to shoot two fletch or if three, two at 180 degrees and one on top, 90 degrees from the other two. Not optimal at all.  
And you can't just cut a groove in the case because the front pin for the latching fork is just under it. If you lower the pin and fork, it really screws up the geometry of the trigger shear. So after some thought and experimenting I was able to change the fork shape, lower the pin, cut the groove in the case and adjust the geometry so the shear surfaces lined up correctly. I also added a trigger spring for more positive lock up, an adjustment screw to dial in trigger creep, and added a built in peep sight to the long claw.  So now I have my Improved Chinese design. Then I had to design it all over to make it more producible. Like using extruded aluminum tubing for the case instead of machining the case from a solid block.
Anyway, probably way more than any one wanted know but it is done now and looks like this:




Anyone with machine tools and experience can make their own. I have posted the details before and I am happy to share design info. PM me if you would like more detail. For any that would like to buy parts or a complete trigger, we will soon have them available. We are targeting just under $40 for a complete drop in.
I have developed the CNC code for my little home CNC router and was able to do a small production run to prove out the fit of parts but only the aluminum parts. The steel parts I had to make on my ancient manual mill. We are working to get the big machines programmed to keep the cost down. My home machine is WAY to slow. The big machines are expensive but FAST.
Here is a view from behind showing the peep site:




Next post I will cover sights, trigger guard, and other CHEAP hardware.
Thanks for reading,
John

Geezer here, commenting on your cheap and easy crossbow.  I see you're binding the prod (lath) in by thing to a peg a few inches behind the prod socket.  Personally I've never liked using a peg: I think going thru a bridle-hole works rather better, but in fact extant ancient Chinese bows DO have a rectangular hole thru the stock in that position, and may well have used some kind of peg.  But it has occurred to me that if you use a square-ish peg and there's a bit of extra room in the peg passage, you could tighten up the bow binding/bridle by driving in a couple of wedges ahead of the 'peg' The wedges would have to be fairly long and shallow so they don't vibrate themselves back out, but I think this would work pretty well.  You'd end up with something halfway between a medieval bound-in prod and a set of renaissance bow irons.  Has anybody tried this?  Geezer.

Warning - Opinion of the author.  
Sights are not absolutely needed but they do make the weapon WAY more accurate. I have always shot my hand bows instinctively, i.e. without sights. But have always of course had sights on my rifles. I can't imagine shooting a rifle without them and to me the Xbow shoots much more like a rifle than a bow.  With one big difference. Even a fast Xbow will never shoot as flat as even a Black Powder a rifle. IMHO, that makes scopes much less useful because it is harder to quickly adjust hold over/under looking through a scope. Especially if magnified. They do work, I have build several Xbows with scopes and still have one now. But I have found that for me at least, the peep sight works the best. Especially in a hunting situation. As always, YMMV. . . .each unto their own, so build what YOU like.
OK Opinion closed.
So if you build or buy a Chinese style or one of my improved Chinese triggers you get the rear sight for FREE ( my favorite price ). Ours will come with it but if you build your own, just drill a hole through the top of the long claw the size you like. I have used 1/8" or a bit larger. The front sight is darn near free with just a little work. It is just a pin sight like used on hand bows with a small "T" bracket. If you have a pin style bow sight, you should be able to use one of the pins from that or possibly purchase one at a Archery supply store. I made one by cutting the head off of a screw, chucking the screw in a hand drill and then grinding the shape I wanted with a Dremel tool as the drill turned it. Kind of a poor man's lathe.
This is the first one I made:



I think the construction is clear from the picture except that you can't see that there is a slot in the bracket where the screw/pin goes through so that it can be adjusted up and down a bit to change range.
Next - cheap trigger guard and arrow holder and stirrup

Geezer wrote:Geezer here, commenting on your cheap and easy crossbow.  I see you're binding the prod (lath) in by thing to a peg a few inches behind the prod socket.  Personally I've never liked using a peg: I think going thru a bridle-hole works rather better, but in fact extant ancient Chinese bows DO have a rectangular hole thru the stock in that position, and may well have used some kind of peg.  But it has occurred to me that if you use a square-ish peg and there's a bit of extra room in the peg passage, you could tighten up the bow binding/bridle by driving in a couple of wedges ahead of the 'peg' The wedges would have to be fairly long and shallow so they don't vibrate themselves back out, but I think this would work pretty well.  You'd end up with something halfway between a medieval bound-in prod and a set of renaissance bow irons.  Has anybody tried this?

Good thoughts Geezer! I was going for easy but I think you right that a through hole would look better and not be a lot more work. And square-ish pegs would be a nice touch, especially if you are going for a historic look. This build was kind of a Star Wars meets the Dark Ages thing.  LOL
I like the wedge idea. I see no reason why it would not work. I may have to try it on my next build!

Geezer -- you're right -- the historic Chinese mechanism used a rectangular "peg" with the long axis of the hole down the length of the tiller.  Not sure if they used long thin wedges to tighten the binding after the fact, but it's certainly possible.  There were two historic binding strategies -- plain loops from the prod around the peg and back again, and the X shaped binding that jaeger22 and I have used.  Aesthetics?

Geezer her on binding bow 'bridles'.  When I started making crossbows, based on Payne Gallwey's book, I used a 3/4 in diameter thru-hole about 3 inches behind the prod socket.  Eventually I discovered the bridle-cord tended to cut into the front surface of the round hole, so I went to a flat-fronted hole (D-shaped) that allowed me to lay the cord out nice and neat, and incidentally reduced cutting into the stock at the front (some medieval bows reinforce the front surface of the D with blocks of horn or bone to make it even more resistant to string cutting into the front surface (I always bevel that flat front so the string doesn't cut on the edges) So the bridle cord loops over and back from side to side, until it's time to tie in the stirrup.  At that point I change to an X pattern over the stirrup (and yes, stirrups sometimes work a bit loose, but that's another note) When a great wad of cord is laid down, I start wrapping up the resulting V skein on each side... pulling very hard, round and round about halfway up the V.  Then I switch to a figure 8 pattern, over and back till most of the space is consumed, and tie the remaining cord off where it can't be seen. 
This whole proceedure can be done with separate cord for bridle and stirrup, then cinched up with more separate pieces, but with a little thought, you can do it all: bridle, stirrup, and cinching with one piece of cord.  That seems to be the way medieval bowyers do it.  My journeywoman, Lightly is a past master at getting the bridle nice and neat.  Mine come out a bit rougher, but tighter, because I'm much stronger.  Note this isn't the only way to do it: it's just the way I do it.  Geezer/DRW/NWA

Thanks Geezer, interesting stuff. It motivated me to look for more information on the historical way they did things and I found this video on Youtube:
Mount of a historical crossbow bow. Bridle
https://www.youtube.com/watch?v=V2VDpAauAZI
I wish I could understand the narrative but it is in German. But the video looks like what you are talking about. Very interesting!

Yup: I believe that's the source Lightly found for doing it approximately right.  We have tried all manner of fibers for binding bows, but nowadays we get 3/16 in. hemp twine online.  It's just about the right stuff for replicating medieval bows.  There are plenty of modern fibers that might well work better, but at least this stuff is really authentic.  Lots of medieval bows painted their bridle/binding with some sort of tarry substance.  That's my next step:  always learning.  Geezer.

So continuing on the cheap easy theme, (not historic for sure) we still need a trigger guard, a stirrup for cocking, and optional but very useful arrow hold down clip of some type. You can easily make the trigger guard and stirrup from aluminum from Home Depot. But the method I will attempt to describe here will use PVC. It does require one more tool. a heat gun. I got mine from Harbor Freight for $12.95, so not an expensive investment and a very useful tool to have.  Many of us have PVC pipe laying around but it is available in Home Depot/Lowe's/Ace in short sections for a couple of bucks. You can make all kinds of stuff with heated and shaped PVC. You can get almost any thickness you want depending on the size pipe you get, and which schedule. I used 3/4" schedule 40 for the trigger guard and hold down clip, and it is about 1/8" thick. I use 1 1/2" for the stirrup as it is a bit thicker material.
So the first step is to split the PVC pipe. You can cut it with any kind of saw but I used a band saw here:


Once you have it split, heat it with the heat gun until it is soft like so:



Then quickly flatten it with a board and put some weight on top to hold it flat. It will cool an a few minutes and you now have your basic working material. Draw your part to your taste with a sharpie and cut out with any kind of saw or sharp knife. Then heat where you want to bend and shape. If you mess up, no worry, just heat and bend again till you get what you want. Once it cools it is surprisingly strong and rigid.


 Follow the same process for all three parts.





The trigger guard base will need to be inlet so that it does not dig into your fingers. I just used an exacto knife and a small chisel as seen here:




Once the back is done, inlet the front:



Krylon Fusion paint for plastic can be used to paint them or you can color them with a sharpie.



Then assemble. Your done!

Nice work jaeger!  I'm a moderator at the G+ group called PVC Archery and Crafting, which is a community of folks who LOVE working with PVC and archery, including prods, tillers and other bits & pieces as well as vertical bows.  Come check out the group: 

https://plus.google.com/communities/115443350092709812365?partnerid=gplp0

Thanks Ken! And thanks for the link! So many cool projects there. I can see I will be spending some time there and I expect getting great ideas for my own projects.
John

Thanks for posting this jaeger, great triggers (looking forward to seeing more of your modified Chinese mech) and I love the "cheap and easy"

Thanks Anatine, the guys at the machine shop have made good progress getting the coding and set up done to mass produce the triggers. I hope to be able to test a complete CNC produced trigger this week. Here are some pictures of what they have so far. Theirs look way better than mine!
Assembled claw.



Claw parts and fork:


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Short claws in the mill jig. Makes 4 at a time:



I will post updates.
John

Great build, Jaeger! No pressure or anything, but I'm holding some choice lumber and a fine steel prod to build around one of your Chinese triggers. Is it ready yet? Is it ready yet? Is it ready yet?
Gnome
p.s.
Is it ready yet?

Yes but it is slow.   The guys at my sons machine shop have made a bunch of all the parts (claws, forks, cases) except the actual triggers. That is the next and last part. But then they all got pulled off to to work a priority job ($). They are saying another week but. .  . .
They plan to send all the aluminum parts to get them anodized black. They should look good.
As soon as they finish this first batch triggers I plan to pick up the first complete ones and do a quick build with it and shoot it a bunch just to make sure everything is good before they sell them.
I will send you a PM about getting a prototype.

I to would appreciate knowing about buying. Thanks Chuck

I will call them tomorrow and get an update. Also push a bit.  
You guys check your PMs.

You don't have to pto. It'll come in time. Just hurry ,he he.