Sunday, 29 May 2011

How to make a Crossbow Prod (Limbs) from old saw blades

Below are a series of pictures showing the process of how to make a Crossbow Prod (Limbs) from old saw blades.

Basic Template  - prod can be 18" or up to 22"
depending on the saw blade you use

Any old saws will do the job for a prod (crossbow limbs)

How to mark out for the prod

Notches of the prod end parts.

Notches of the prod end parts.

Clamp the wood between two pieces of wood to use as a guide
to aid cutting with the angle grinder

This is the waste material.

How to make the string end caps from Aluminium,
cut along dot line, file to shape, drill holes

End caps in place (need a bit more filing still yet)

End caps in place (need a bit more filing still yet)
How to make Cross bow prod - this technique will produce a prod of around 50-65lbs draw weight when using 5 sections of 18" blade steel, longer sections and more parts will produce stronger prods, the draw length for this prod is about 7" inches.
Materials : 5 old saw blades, some 1/4" aluminium, 4 x bolts, locking nuts and washers, black electrical tape.
Tools for the Prod : Angle Grinder, Vice, safety gear, two pieces of wood (any length as long as its bigger than the saw blades), Marker pen.
End Caps : Drill, Files, hacksaw.

First thing to do is mark out the prod as shown above, clamp the saw between the wood as shown, I use screws and then I lay the whole thing on the floor and cut it that way, the saw blades will take a fair bit to cut, so it may take a few minutes to cut one blade (5-10mins possible)
Once roughly cut out put a section of blade in the vice and grind or file the edges smooth so they are not rough anymore, then using the grinder cut in the prod end grooves, do these things on all 5 sections.
You will then have the basic prod, but will still need the end caps for the string.

Cut two piece of 1/4 aluminum to the sizes shown above, cut out the basic shape and then using files shape it to the finished shape, drill the holes (about 4 - 5mm) the position may vary depending on where you cut the end groove on the saw blades.
Once the end caps are shaped you just need to prepare the parts.

What I do is get the 5 sections and tape them together with the tape, don't cover the whole prod , just do it in bands as wide as the tap itself, and leave the ends free so you can bolt on the end caps,

Once I have the tape on I then bolt on the end caps on the outside edge of the prod (bolt on either side, just make sure when you use it the end caps are on the outside)
Once bolted on, cut of any of the bolts that's stick out past the nuts and wrap the end in tape as shown above.

About the string : This size prod will be able to use a bought pistol prod string, but you can make one from most strong, non stretching string.

You should now have a full working Prod ready for your crossbow. I hope this tutorial helped.





Please leave a comment letting me know what you think and if you have any questions just ask.



1 comment:

  1. Very nice tutorial! By the pictures the *old* saw blades you used, didn't seem to so old. I was wondering if I could use and old two-man saw blade i got laying around, but that's all rusty and stuff.. I don't know if it is all corroded and i just wanted to ask wouldn't it be risky to use that, or is there any way I could make sure its good, like sand it shiny and see how thick it is... Thanks and again, nice lessons, i really like the crossbow stuff!

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