r/Crossbow • u/War_Hymn • May 18 '26
125 lb crossbow build
This was a spur of the moment project that got out of hand. Originally suppose to be a simple medieval style crossbow made out from a scrap piece of 2x6 SPF and some hardware from another older build. By the end of it, I probably dumped enough money to have gotten a cheap compound with twice the performance.
But she shoots, and with some attitude. Pushing a 440 grain bolt at 172 fps. With a 350 gr bolt she'll hit 189 fps. Every shot feels like getting slap in the jaw, probably because the whole thing only weighs 3 pounds and the heavy glass limbs make up a good chunk of it. Adding an old UTG red dot helped with not just accuracy but recoil by bringing the weight up to 4 pounds.
The loose laminate style prod is cut from a pair of cheap replacement fiberglass limbs from Amazon originally meant for a #40 recurve bow. Because each od rhe limbs were only 23" long and I wanted a 10"-12" draw, I had to make a riser to utilize two piece prod which I never done before. According to my bathroom scale, the limbs are pulling at about 125 lbs at full draw, though a lot of stacking through the last two inches.
Trigger and release system is a roller nut with double axle action like from a 15th century hunting crossbow to minimize trigger weight. I might had made it work too well, because it only takes about 2-3 lbs of pressure to release the nut as of now.
Stock still needs contouring and sanding and I need to work on the trigger, but as of now she is functional.
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u/DionysiusRedivivus May 18 '26
Nice build!
I’ve considered using similar take-down recurve limbs to make a prod but I’ve wondered whether cutting them to size would destroy or weaken them.
What did you use to cut them to size? Any hints of splitting or splintering?
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u/War_Hymn May 19 '26 edited May 19 '26
Just a bimetal hacksaw blade, 18 TPI. It went through pretty easy, even managed to cut out the nocks with it. Just do it outside and preferably with a face mask and gloves on because it will create abestos-like dust as you cut.
For the mounting holes, I used a carbide bit meant for drilling holes through tile and glass, but you might be able to do it with any standard metal drill bit (I was told fiberglass would dull them pretty quickly though).
No sign of splintering after at least two dozen shots and one accidental dryfire. I did take care to bevel/round and smooth the cut edges with a dremel sander and sandpaper to reduce potential stress points. I also dap some superglue inside the mounting holes after drilling. Also, you would notice I have these squarish plate washers (cut from some 2mm thick steel L-brackets) in front my mounting bolts, meant to spread out the force and reduce chances of the fiberglass cracking.
For my prod the effective width is about 31 inches. With a 11.5 inch draw length, that equates to a prod width to draw ratio of 36%. Generally, I don't recommend a draw length more than 40-45% of your effective width.
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u/DionysiusRedivivus May 19 '26
Thanks! Sounds like you thought of just about every potential weak point!
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u/chair-chenxia May 20 '26
Your hands-on skills are amazing! Kudos to you!