Hickory Board bow questions - New Pics Added

[kountzer0]

Ok so I started a hickory board bow project.  1 3/4 inch wide at fades pyramid limbs to 1/2 inch 66 in ntn, 8" stiff handle type. Aiming for 55lbs at 28" hoping it will shoot into 50lbs after break in etc.

I roughed it out with a borrowed 10" bandsaw and my hand planes.  The back has been sanded very smooth and corners rounded.

I made a long string and put it on the tillering stick.  At about 10" of string travel, the limbs are bending pretty evenly and hitting 50lbs on my cheap scale.  The distance from the ground to the limb tips differs by 1/2 inch or so.

No hinges yet or really noticeable flats. No set, in fact the board acclimated in my garage with about 1 1/2 inches of reflex, of which about 1/2 inch remains.

So I was planning to just go slowly with my cabinet scraper, counting strokes along the whole length of each working limb.

Does that sound right?  When do I brace it?  Is it so stiff that this method of removal will take forever?

Thanks for the help!  As I get more bend in it and get closer I'll post pics.

[Pat B]

If you have bent the tips to 10" and both limbs are bending evenly and together it is time for a short string and a low brace height of about 3" to 4". This will give you a true reading of string track and how well the limbs are bending.

[kountzer0]

Thank you PatB!

So...for the short string with low brace...it would seem that the 3" shorter than bow length would be a bit too short.  I've never done this before.  Should I make a string 2" shorter  and twist it once the bow is closer to full brace, or is 1" too much to take out with twists?

My string material is b50 dacron.

[John Scifres]

I wouldn't brace it just yet.  50# @ 10" is too strong IMO.  I like to get the bow bending around 10# short of target weight (40# in this case) at 16" or so.  That gives me plenty of room to work with and still retains the spirit of the bow.  Just keep your string barely tight for now.  Make a single loop tillering string that you can adjust the length on with a timber hitch knot.

I wouldn't switch to the scraper just yet either.  Judicious and careful rasping is as controlled and will save you tons of time.  Just don't dish it.  Long, smooth strokes.

Oh yeah, and post pics  

[don s]

i was reviewing my TBB on pyramid limbs. i would like to add that you want to make sure your limbs are perfectly rectangular in cross section. this allows for your near handle wood to bend without being overstrained or to blow on you.
      don

[kountzer0]

John:  Thanks for the tips!  I'll grab my rasp and keep the handplanes at bay!

Don S:  I read the same thing, which is one reason i went with the pyramid limb design.  No thickness taper seemed easier to me in concept.

Added plus is the tillering gizmo tends to lead to arc of circle by it's nature.

I wanted to get a start so i dove in after too much reading  

[kountzer0]

Another question:

I'm in Phoenix and our humidity in winter is very low (like 11% today).

Should I be worried?

I intend to do some tillering work this weekend so if i get a chance I'll post some pics as requested.

Thank you all again.

[George Tsoukalas]

Yes, brace it. 50# at 10 inches with the long string translates to 60# at 26 in. Just about right. That is how I do my bows except for the reflexed ones. I brace them sooner lately. Reflexed bows are little liars. They show early draw weight and lull you into thinking they are too heavy.  Brace it. No don't worry about the low humidity. Jawge

[kountzer0]

Thank you George.  Will do.

Thank you Pat, John and Don.

You all are providing an invaluable service to all of us.  I really appreciate you sharing your experience.

Jeff

[kountzer0]

Mkay tired of this thread yet?  If not please read on:

I didn't get a chance to work on the bow much this weekend but life goes on regardless.

I did do some scraping here and there and I made a flemish string with 1 loop and 1 hitch.  I can brace the bow to 6" and draw it on the tillering stick.  After exercising the limbs it now pulls 50# at 18".  No huge hinges. One limb is noticeably stiffer, but it's mostly near fade to midlimb bending so it will get worked out.

The other limb wants to twist.  I cant "feel" a thickness difference from one side of the limb to the other - but that's not to say it ain't there in spades!  Looking down the limb from fades to tip with a good bend on the tillering stick one side of the limb is higher that the other.

Which is the stiffer side of the limb?  The high one or the low one?

Anyways this is WAY too much fun!  I've been called a crack dealer for teaching folks to fly-fish, but heck my buddies ain't seen nothing yet!  buy stock in rasp makers and such while you still can!  

[kountzer0]

I did a little more with the scraper.  The twist is a lot tamer now.

I made my 1st flemish string and it didn't blow up   :D  

Here she is braced at 5"

 

And here at 21" pulling 37ish pounds:
 

Please comment on tiller.  I know what i see in the pictures, but I'd like your opinion as I'm just amazed it bends.

[George Tsoukalas]

It looks good but that right limb looks stiffer mid limb on than the left. But the cement blocks don't show that. Is she still twisted? Jawge

[okie64]

Looks like the right limb is a little stiffer in the inner and midlimb area.

[Rain Man]

i agree with them.  Right limb is stiffer

[kountzer0]

A little more "work" done, although I'm lying if I use that term regarding this project        

The twist is gone, the same limb is still a bit stiffer, and she's pulling 50# at 28" draw.

I backed her in linen with TBIII due to rampant paranoia streak.  

Here she is braced at 6"
   

Here she is at 28":
   

I left her strung for about 30 minutes, excercised the limbs etc before these photos.
I've shot the bow 50 times with arrows that are a bit too light for this weight (400gr carbons from my wheelbow gadget-slavery kit).

I have to say I dig it.  She's been unstrung for a day and when laid on her back, the back of the tips are 1" off the ground - I think this is set and not string follow?

So I guess you guys got me.  This is way too much fun to ignore.    

[GREG IN MALAD]

For a pyramid design I think it looks really good. The right side looks a bit stiff at midlimb but I think it's caused by the block wall behind it. Set and string follow are the same thing, also I think 11% humidity can cause problems, I think that translates to about 3% moisture content. Hickory likes low moisture content but that's really low. 1" of relaxed set is pretty good.

[PEARL DRUMS]

I second Greg, 1" of follow is dang good with hickory. Good work! I see the stiff spot you refer to, cant tell if its the wall or not?

[kountzer0]

It's amazing what you see in the photos after the fact