Short Board Bow Draw Length

[StickandString88]

I picked up a couple clear straight grained maple boards the other day. One had some run out at one end so I decided to cut it down to 58” and use it to practice my tillering with before I work on the better board. I built a couple board bows back when I was in college but they were crude and I didn’t have all the right tools I’ve got all the right tools now and built a tillering tree with a pulley recently so I’m ready to get after it. I have a couple questions on the short board. I made it a parallel width of 1.5” and then tapered to 1/2 nocks starting at 10” from the tips. I have left the 4” handle section full 3/4” thickness like George's board bow build along. I was planning to tiller it out to approx. 20-22” since it’s so short and want it to be a little overbuilt since I’m sure my tiller won’t be perfect. Does that sound reasonable? Also, what brace height would be typical a D bow of that length?

[RyanY]

Reasonable draw length for a rigid handle short bow like that or very reasonable for a bendy handle bow. What draw weight are you going for? My bows of that length usually end up around 5-5.5” brace height.

[StickandString88]

Reasonable draw length for a rigid handle short bow like that or very reasonable for a bendy handle bow. What draw weight are you going for? My bows of that length usually end up around 5-5.5” brace height.

Thanks

I’m going for approx. 40-45 lbs draw weight. Right now it is pulling 30# at 15” with a short 4” brace height. If I increase the brace height an inch will that probably just raise the draw weight by 2-3 lbs like pulling it an extra inch of draw length?

 

[RyanY]

Raising the brace height won’t have an impact on draw weight. Sounds like a reasonable weight for that style bow.

[StickandString88]

I have it braced at 6” and have pulled it to 15” in the picture below. What do you guys think of the tiller?

[Jackpineboyz]

the bench and the back wall lines through the eye off a little but I think it is a pretty good tiller there.
You are probably pretty close for your desired bow weight.
I like to flex them a bit at a short draw for a bit, unstring for a few hours and recheck the next day to make sure its still looking balanced.
I then work it up to draw or an inch short if I'm doing a high stress design.  If things look good I draw by hand and record with a phone or in a mirror for final tillering.  Everyone holds a bow different so you can fine tune based on your draw style (+ or - tiller, etc).  I had a bow look beautiful on the tree, but looked overstressed on the bottom limb with three under. Basing the final tiller off my draw a think is more practical. 
You do want the tiller close on the tree for sure, and be sure there are no hinges etc.
 
With your stiff handle I could see it handling 25 " in the 45# range, but I'm not experienced with a maple board bow.  Work up slow, I think it will be a nice bow at 22" goal.

Are you doing any backing, or simple self bow?  I do like the grain of maple.

[StickandString88]

It is currently unbacked. I had contemplated backing given my lack of experience but I feel like the tiller is halfway decent for my first serious attempt at a bow. With the 6” inch brace height it pulled 35# at 15” so it shouldn’t be hard to hit my target weight or a little higher.

[RyanY]

Given your width taper it should bend more in the outer 1/3rd of the limb for a more elliptical shape for more even strain.

[TimBo]

It looks to me like the LH limb is stronger (although the background is a bit busy as mentioned, so maybe I am seeing things).  If you draw it using the same fulcrum, does that limb tip towards you?  If it does, you could just move your grip away from the stiffer limb until you find the sweet spot shooting-wise (or where neither limb tips).

[aznboi3644]

You should be good for a 26” draw easy. My 57” hickory board bow will draw 26” with ease.  It’s a bendy handle