Tapering Hickory Backing and Dimension ?

[SteveL]

Howdy Gents,

Welp, can't resist the urge to build my first wood bow. I have a piece of hickory for backing and a nice osage slat. I've read where I should taper the the hickory, but I'm a little confused as to which side should be tapered - are we talking about the side that is glued to the osage? And how thin should I make it at the tips?

Also should I taper the oasage on the belly side before glue up? I plan on putting a little reflex in the limbs.

Any suggestions on general dimensions for a 50 pound bow at 28"?

Thanks!
Steve

[Pat B]

What are the dimensions of your osage stave?
 I've made many hickory backed bows and never tapered the backing. I prefer hickory backings of 1/8" or slightly less. I also pre-tiller the belly to floor tiller or just beyond so you get each limb bending well and both limbs close to each other. I usually add 3" or 4" of Perry reflex at glue-up and want both limbs bending as closely to each other as possible at glue-up. This usually results in a bow with a flat or slight reflex side profile.

[SteveL]

Hi Pat,

The osage is about 11/16 x 1 1/2 x 66. The hickory is around 3/16 inches thick.

What is Perry Reflex?

[macbow]

The hickory backing will need to be thinned a little. Max 1/8"
Rather,than trying to explain Perry Reflex, try googling first.
Also the archives here should have some info.

The 11/16 will make,a much heavier than 50 pound draw.
So tapering,from outside the handle,area on the belly side before glue up would be a good idea.
Maybe 1/2 inch in the handle area to 3/8 thick at the nock ends. If you leave it the full 66 inches that will give you room to pike the ends ( shorten) if needed to add weight.

[Pat B]

I'd leave the handle area full thickness to be sure it remains stiff through the draw. The least bit of bending in the handle area will cause the handle riser to pop off.
 I make bows symmetrical with the center of the handle the center of the bow. When I lay out a bow I mark the center, lengthwise, then measure 2" above and below the center line for the handle and 1 1/2" to 2" each side of that for the fades. 1 3/8" to 1 1/2" wide at the fades, out 8" then a straight taper to the tips. I'd leave the tips 5/8" wide until after first brace so you can see how the string tracks. You can reduce the tips to 3/8" after you know everything lines up. I don't shape the handle until later either in case you have to move the handle to one side or the other.
 Now draw out the side profile on each side of each limb and begin reducing. The limb thickness that macbow suggested should work fine. With those thicknesses the limbs should bend nicely when you glue it up.
 Basically Perry reflex is adding reflex at glue up time by clamping the handle to the work table, back up, and the tips lifted up on 4" blocks. I use end cuts of 2x4.
 You can reduce the hickory backing strip to 1/8" or less on a belt sander.
 Here is a handle I did a few years ago on a hickory backed lemonwood bow. See how I left the lemonwood full thickness at the handle and faded into the limbs...
 

   

 Here I left the tips wide to begin with...
 

Then reduced the tip width, added the tip overlays...
 

...and the final shaping of the tips...
 

 

[Pat B]

This is a little trick that Pearl Drums told me about. You drill 2, 1/8" holes through the backing into the belly and use bamboo skewers as alignment pins to hold the backing in place as you put the bow together...
 

..and in this pic you will see the glue up after the glue had set. Note the tips on 2x4 blocks and the handle was clamped down to the bench. I used bike inner tubes to wrap/clamp the glue-up.