Shortening riser?

[pditto613]

Made my first take down recurve.   Turned out nice but came in a little light @46#
If I put the same limbs on a 2" shorter riser how much draw weight do you think it will add?

[Roy from Pa]

About 5 #.

[Mad Max]

About 5 #.

yep

[pditto613]

That's what I thought.  Thanks

[Crooked Stic]

Last time I shortened a riser 2 inches only gain 2 lbs.  So I would be interested to see how you come out. Think you gain more with shorter limbs

[Bow Bender]

You can make a pair of tapered wedges to go between the limbs and riser.  You can experiment with different tapers until you find the correct one.

[pditto613]

Bender you mean use wedges to change the pad angle?   If I took off 2 degrees how much of a change do you think that would make?

[Bow Bender]

Yes. That's what I mean. I don't remember who it was but once upon a time there was a bow manufacturer that made wedges just for the purpose of changing the draw weight on their take down bows. Maybe someone else remembers who it was and can chime in here. For those that don't know, the poundage and tiller is adjusted on wheelie bows by adjusting the limb bolts up or down . To make a durable set of wedges take a couple scrap pieces of fiberglass that you probably have leftover from making the limbs, cut the length and width to match the limb pad and laminate a piece of wood to one side of each. They should be thick enough to end up with a thick end and ground down to thin at the other end creating a wedge.  Probably should drill limb bolt and alignment pin holes before tapering.  Having the wood laminated to the fiberglass makes it durable and prevents splitting. Make the thick end whatever thickness you want to change the limb pad angle,  just make both the same. Experiment with different wedge angles.  Wedge can be made so they are reversible allowing you to increase or decrease poundage. These can be very useful in making changes in poundage to help fine tune a bow/arrow combination.

[Bow Bender]

I don't know what the poundage change would be for a 2 degree change,  that isn't very much.  Start with 1/4 inch difference from thin to thick end. They  can always be ground down.

[pditto613]

I have some 1/4" phenolic that I could use.  Will probably have to replace the alignment pins with longer ones to make it work.  I will play with that tomorrow

[Bow Bender]

 
Keep us posted.

[pditto613]

Limb pad wedge

[pditto613]

First, I was wrong about the weight of the bow.   It is 50# not 46#. Didn't check zero on my scale.    The first wedge tapered from 1/16" to 1/4".  It was just under 5 degrees.   It moved the limb tips forward 1 1/16" and increased the draw to 56#.   More than I was looking for.   Second try changed it to a 3 degree taper and increased to draw to 53#.  This is closer to what I was after.

[Flem]

What wood did you make that riser from? Looks nice

[Mad Max]

Awesome

[Bow Bender]

Great!  As long as changing the limb pad angle doesn't move the limb tips so far that the poundage starts to stack at your draw length this is an easy fix.  If this is the poundage that you want you can permanently install the wedges on the riser or the limbs or leave them removable to experiment with on future builds. Now wasn't that a lot easier than making a new riser? And look at what has been learned about just a small change in pad angle for designing your next riser.

[pditto613]

Bender I believe you are right about the stacking when it was an extra 5 degrees.  It hit a wall around 27". Wish my chronograph still worked it would be interesting to see the speed difference. Flem  that riser is laminated red oak.   It was a prototype first build and I didn't want to use the good stuff.   So I stained it as dark With minwax true black.  Now I kind of like the simplicity of it.  I will post some pics tomorrow, it is hanging in my spray area drying right now

[pditto613]

58" take down.  53# with wedges.  50# without

[pditto613]

.

[Mad Max]

Nice