integrity of bow after center shot cut out

[Dennis G]

I"m working on a 2"nd red oak board bow and have a couple of questions.
  This design uses a 2 1/2" wide board which tapers to 3/8" on the ends and then fades to a 1" wide handle area. Original design handle was 4", I'm making mine 6" so I'll have room for an arrow shelf. with the handle wood glued on it's 1 1/2" thick, is the handle too narow (1") to cut to center? I"m, shooting for a 40# to 45# bow.
 my 1'st bow took a couple inches of set which Im hoping to avoid on this one. Ive been advised to let the roughed out bow dry for a couple of weeks before tillering. I also was advised to back the bow with raw hide or sinew and clamp it in a reflexed position while it dries.
 Is there any way to use the silk I alresdy have and still avoid a lot of set?
thanks, Dennis  

[LittleBen]

IMO 1" is wide enough to cut to center, however, I'd probably make the handle area thicker than 1.5" just for safety, maybe 2" or even 1.75" would make a big difference in stiffness.

The other thing is to make sure the shelf anf the sight window meet in a rounded off corner. A sharp 90degree corner will concentrate stress. I typically will use a rat tail file to make the transition between the shelf and sight window a small radius curve to prevent splitting there.

I cut basically all my bows at or near center and haven't had any problems, but I also usually leave them a little wider than 1". more like 1.25-1.5" wide. I also usually build only around 40-45#.

Good luck.

[Pat B]

Generally set happens due to overstressing while tillering. Some woods are more susceptible than others and red oak is one that will take on more set. A backing like silk or rawhide will have little affect on whether your bow takes more of less set. It is more for preventing a splinter from lifting on the back.
  Trying to cut any wood bow to center is risky. A 1" wide handle is as narrow as I would go. With properly spined arrows it shouldn't make a difference. I you want an arrow rest I would add one on the side of the handle. See my "68" hickory Backed Lemonwood" thread. It show how I added a shelf using thick shoe leather.

[Dennis G]

Thanks, how do I avoid overstressing during tillering. Previously I would draw the bow about 30 times after each change, either after removing any wood or after moving up an inch of draw during tillering.

[fujimo]

sounds like you are doing it right.
never draw past your intended draw weight- irrespective of the draw length you are at, and fix anything at the first sign of it, hinges, stiff spots etc.

sounds like you are doing fine.
but some woods will just take a little more set than others- i think all woods will take some set to a lesser or greater degree- heck even glass bows will take a teeny bit of set( although i am very new to glass bows- so dont take any, ANY glass advice from me!!!!)

[John Scifres]

I don't see what advantage there would be to cutting a 1" wide handle to center.  What are you after with that?

2" of set on red oak is better than average.

[Roy from Pa]

I wouldn't cut a shelf in on a 1" handle. Make a leather rest like this.
 

 

 

[Dennis G]

All good info, feel a lot better about my 1st bow, met a couple of seasoned bowyers who teased me about the shape of the bow, said it looked like I was stringing it backwards! Thanks, Dennis

[fujimo]

ignore them- yer doing great. ask them how it looks after you poke em in the eye with it  :D

[Dennis G]

Here are some pics of both bows:

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[Dennis G]

this is the unstrung bow belly down resting on the tips showing how much set set, a little under 2" to the handle.

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[Dennis G]

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[Dennis G]

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[fujimo]

so an easy way to measure the set is lay it on its back on a table, say. and then measure from the table to the tips.- you will get a different measurement than you are getting now.
cant really tell , cos of the angle- but it might look like you dont have enough bend in the inner third of the limbs. or she looks a little whip tillered- hard to say for sure without a square on pic.
that will lend itself to some set, as the entire limb is not working,
need to spread that load as much as possible over the entire bow.
 gotta get one of these smartie pants on here to show you how to use the eliptical tool on the 'puter, really helps with understanding the shape required.
i try to just eyeball it- being a techno-peasant.

[Dennis G]

Ok, here's on the tillering tree for a better look?

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[John Scifres]

Tiller looks pretty good.  The lower limb appears to be bending more than the upper.  Where is your set concentrated?  I think I would try to get a little more bend in the upper limb, from the handle to midlimb.  Most of your bend is from midlimb out on the upper.

[fujimo]

one thing i found , for me...that was inducing a lot of set, was drawing the bow back on a tillering stick, hooking the string , and then spending a little time studying the bow from all angles. it helped me understand shape a bit better, but those extended periods under high stress do a wood bow no good. even more than a second or two is no good for them. now i have a pulley at the base of the tree, and with my scale hooked to the string, and a rope to the scale- i can draw back to my draw weight get a look for a second and release, and do that as many times as i need to to study the shape. if i want to take a photo- i get my assistant to do that while i draw the bow  back.
cant see clearly- but looks like you might have a similar setup.

looking at it, i would say that you could still use a little more bend in the inner third- your middle thirds are doing all the work right now, and the left limb looks a wee bit  whip tillered, but the right limb tip looks good.

i know the first few bows i built- all i wanted to do was cut in a shelf-  and i did the first few. until i understood more about arrow dynamics- now i dont do that anymore on my wooden bows, in fact i have moved away from rigid handled bows to bendy handled bows,
but hear the guys above- a cut in shelf adds no advantage- use a glue on shelf- or even a floppy rest. if anything, on a wooden bow- it possibly creates a potential weak point.

[fujimo]

oops john must have been typing same time as me.- not trying to contradict john at all- listen to him - he knows his stuff

[Dennis G]

Wow. Thanks for the excellent feedback. I'm reluctant to take any more wood from this bow since it's already reduced to a 30lb bow, but l think I know now where I messed up. I was pretty far along in tillering before I realized that the inner limbs weren't bending enough so I then removed a fair amount of wood from the inner limbs, but the outer limbs had already taken a some set. Hopefully I'll do better on this next bow.

[Dennis G]

Also must confess I accidentally left it drawn to 26"  overnight, sure that didn't help.