Finished Crossbow - Thanks to all - here some pic and if anyone wants info let me know happy to help .

Hi Guys 

Thanks to anyone gave info and i read a lot here - 
this was supposed to be 100% home made crossbow but snapped my bamboo and timber prod , made PVC one didn't like the look so Bought a £20 taiwanese one from ebay - here some details if anyone want more info Just ask 

Stock - Glued up ELM 
plates around prod and stock end  - Stainless steel 1.2mm
Prod - 160lbs Taiwanese from ebay 
String - Homemade Dacron B50 28 strands , long bow serving material and Doubled Served in centre with strong Linen thread covered in bees wax
Trigger- took Pic of Chinese one - used photoshop slightly enlarge - cut out and made in timber for trial then Aluminium 4mm side plates and 9-10mm for trigger and other parts (roll nut part made from 3 pieces of 4mm glued and screwed together (used tap and die set make thread) - then oak spacer plates and springs found in a draw ..
(did have trouble this trigger not holding string weight but slight file a better angle on parts now rock solid) 
Safety made from bolt with part ground away, home made aluminium thumb push screw and glued on , brass cover washer  
Side cover plates- unknown timber 8-9mm thick held on with M4 brass machine screws into Glued in threaded inserts 
foot stripup - strip Aluminium i had 
ash timber to cover roller nut 
Bolt/arrow holder - bit old bandsaw blade 
Bolts made from leftover timber IPE , OAK , Maple - ones 9.5mm home made dowel - turkey feathers and arrow points ..
Finished sanding to 240grit then sanding sealer then several coats Danish oil - then beeswax on arrow bed and edges where string will touch 

Think thats all for now ask if any questions ..
mark 

Couple more pics have plenty during build - if anyone want let me know as have to shrink the size first ..
Cheers Mark 

couple more 

Hi Mark - thanks for the info on my post. There are great pics here too. Can you post a larger pic of your trigger mechanism? Beautiful crossbow!

here you go - 1st pic was chinese one from internet pic then i edited it in Black and white ,I printed it out on paper couple times till was happy for size for my stock as chinese one was quite small .
Then cut out in wood by hand for proof it worked - 
after cut out bit oversized In Aluminium .
only part hard to see is roller nut made of three pieces aluminium sandwiched together then glued and screwed - i felt this was easier then grinding middle of roller nut and more accurate .. 
any thing else mate happy to help 

more 

few more - Last pic is my safety sticking out the side - sorry no picture of that myself but will try and explain

Ok 
here is one picture NOT MINE found online after i made mine but a similar idea to help explain .
I think this picture is better then mine and far easier to make and do - and next time i take apart my trigger i might make similar and make like this - same as mine just a better fixing idea - + couple washers 

What I did was i took a dome head carriage Bolt (filed off the square part under the head) then worked out where i needed to file it and then I filed half the shaft away (like in picture) - 
This then goes through the stock - through the trigger drop in Mechanism and the other end it has a shaped NUT "i used aluminium cut a finger push taped it with tap and die set .
cut the thread exact length so i could put on tight and thread hit end of nut - i glued on with epoxy also for security - 
but many ways to do this same system and lots other safety systems far better out there .

you can see on my close up of trigger mech on central far right a hole through - this is where the safety goes - turn 180˚ its on turn 180˚ other way its able to fire .. - all it does is stop the trigger being pulled - 100% manual no self return so i have to cock the cross bow (put string behind roller nut) then put safety on , load a bolt , aim turn safety to fire the can fire ..
hoe that Makes sense - let me know if anything more you need 

Well done, like the trigger!... though look out for wear and galling on the sear faces if aluminium.

globalmark
 
   Your info is very appreciated and very interesting ,,,,,,,,,,,Great Job

Chaz

Hi Guys 
Thanks for that - 

Andy , cheers i will keep a look out for wear ,i also have plenty meat left on the parts so can refile probably at least once and maybe replace main trigger parts in steel easy enough .. as made as lift out unit .
Mark

Hi Mark - can you tell me the draw length of that prod? I have the same one and just want to make sure that my measurements are in the ballpark. Thanks!

Hi Mate 

I contacted the seller and the European importers in Holland neither could tell me - 
but a i did heaps of googling and found some people say 11" some say 12" and some even said 13" - so i put on my tillering tree and could comfortable get max 12-12.5" and would get 13" but i was not comfortable - 

so i ended up setting it at close 11 3/4" - but think you can set 12" and also ok ..
with my set up i can comfortable cock this by 2 hands on the string and foot in stirup so dont need any cocking string or anything .

I have just added a very basic dry fire Mech (basically a bit aluminium on a string just infront of rollernut - will add pics when all finished and pretty.

hope that helps 
Mark

Perfect, that info will definitely be handy. I appreciate the help!

The Chinese fiberglass prods, approx 27 inches long are copies of the old Barnett fiberglass prods... also seen on Italian San Marino crossbows..  I would say go for about 12 inches from belly of prod to the lock, give or take half an inch.  Geezer.

Few adaptions made - added a red dot sight , then could not raise the adjustment enough so had to add a shim (aluminium wedge under sight mount) 
see Pics ..
Also added a simple Dry fire hook (or whatever you call it) - this is a simple slightly hooked shape piece aluminium held down with a spring with a bolt as a pivot . 
Mark 

Great job, congratulations!!!. I would like to know how do you cock the string.
Manuel Salazar
Guadalajara

Hi 
1st step I do make sure my safe on fire 
2nd pull trigger while crossbow facing ground just to make sure roll nut part is down and correct placement
3rd Cocking this quite easy - just foot in stirrup and one hand each side of stock pull gently with slight harder pull at end - only 160lbs - (think 175lbs would be my max manual cocking)
can easy do 100 times in a day before get to tired - it seems more technic then strength ..

only one thing i notice is since made dry fire mechnism if dont cock perfectly 1st time the string holds with the dry fire bit and you have to just pull that extra 1" after which is a bit trickier but still not to hard .

Mark

Hi Mark, One thing I really like about your roller knut is that it's made in three pieces. To convert it to steel I would just make a new center piece for the knut. That would be any easy way to start to convert to a steel trigger.I use a steel insert similar to that when I use delrin for material.The  two other flat pieces are a piece of cake compared to hacking out a new complete knut. Very good looking little bow you made. I really like the back end grain of the stock , it's beautiful. Also , you were very smart to incorporate the anti dry fire. In the long run , it's not a matter of how you dry fired , It's actually a matter of when . If you shoot long enough ,I'll guarantee you it'll happen. Don't ask how I know this.

Hi Mark,
Great looking crossbow! I really like how you inlet the stock under the plates in front for the foot stirrup to pivot, and the lock mechanism looks like a sweet design. I thought the draw length looked a little short, and compared to the builds I've done with the same prod, it is. I like 14 total inches from belly to lock, 3 inch brace height and 11 inch power stroke. The prod holds up fine, but the generic factory strings don't like it and start to come apart pretty quick so I always make my own anyway. I think you're well within the safety zone, and stressing parts to failure isn't all it's cracked up to be LOL.
Keep up the good work!
Gnome

reading back through posts,as I do when I've nothing to do, I come onto a mention about adding a safety. While the way used was effective, a better approach would be to block the sear instead of the trigger. A more "safe" way, so to speak.Reason being , triggers are often set very light and a good strong jar would fire it.