I'm trying to think of a cool way to set up a device for measuring the draw weight of a bow at various draw lengths. I have the heavy duty scale (white rectangle with the hook). I'm curious how others do this. There has to be some way to hold the bow and hook up the scale to the string. If you guys don't mind sharing your designs...
I put a 2"x4' about 6' long in a black and decker workmate and clamped it narrow side up. I drilled and screwed in a 1/2" lag bolt on each end about 3" back so the 2"x4" would not split. One lag was thru a piece of 1/2" pvc pipe. That is the one I put the grip of the bow on so it doesn't get marred. I hook the scale on the bowstring and with a cheap block and tackle hooked on the other lag bolt I pull on the other end of the scale. The 2"x4" is marked in inches so at any draw lenght I can see the poundage as I slowly pull on the block and tackle.
Here's my set up- I use a crank with a hook attached to my scale that has a holder for the bow at the top- I put this on a couple of saw horses to get it off the ground.
(http://i290.photobucket.com/albums/ll259/truxturning/Brads%20bow%202010/BradsBow056.jpg)
(http://i290.photobucket.com/albums/ll259/truxturning/RD%20Trade%20Bow/RDTradeBow016.jpg)
Trux
I have the same exact set-up and destroyed two good bows doing a force-draw graph. Holding both bows at full draw 30" while writing down the specs and they both exploded.
How do you release that set up without causing undue stress on the bow. Looks like a good old fashioned balliste.
I'm rigging a double pulley system so that when I pull the rope the bow string lifts the weight off the ground. All I have to do is change the weight for whatever poundage I want. No scale.
QuoteOriginally posted by razorback:
How do you release that set up without causing undue stress on the bow. Looks like a good old fashioned balliste.
Just reverse the pully with a switch and uncrank it..
JamesV I had a bow get away once using the hand held method- was quite the sight bouncing around the garage-lol
Ah come on now Trux, fess up son. Your building a high tech traditional crossbow:)
QuoteOriginally posted by Roy from Pa:
Ah come on now Trux, fess up son. Your building a high tech traditional crossbow:)
You're on to me Roy- just need to round the corners on this one to make it a shoulder mount crossbow...