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Main Boards => The Bowyer's Bench => Topic started by: 3-D Longbow on February 23, 2009, 06:24:00 PM

Title: stacking/sanding?
Post by: 3-D Longbow on February 23, 2009, 06:24:00 PM
A while back i posted some picks of my next bow. This bow is my third bow and some might rember i made the riser too small around the grip and it snaped.. Well i have the new riser about done and will post some picks soon.
     The bow is 62 inch take down long bow drawing 63 at 30 in. I wouldn't mind loosing about 3 more pounds,the tips are about 1/2 in. but on this bow i descided to measure the draw weight at every inch through the draw. It draws 2lb for every inch from brace to about 23in. then jumps to 3 lb. per inch  through 28 then to 4lb. at 29 and at 30in..
     Now my question, is there any chance i can reduce some of this stacking by my final sanding?
     If so where would be the best place mid limb? more towards the wedge? or tip? I have slightly traped the lims but could go more.
    Is this somthing that can be done at this point or make adjustment on the next bow.
     Any thoughts?
later
scott
Title: Re: stacking/sanding?
Post by: firewater100 on February 23, 2009, 06:29:00 PM
sorry guys i didnt relize my boy was still signed when i posted this link. but its me firewater..  any help would be a big help .. thank

scott
Title: Re: stacking/sanding?
Post by: Buckeyehunter on February 23, 2009, 06:33:00 PM
I'm not a laminate bow maker, but my understanding is that stack is largely due to string angle.  Thus, I would think sanding more towards the riser would be appropriate.  Is your bow bending most from mid limb towards the tips?  That's my 2 cents, but I would wait for response from more knowledgeable bowyers before proceeding.
Title: Re: stacking/sanding?
Post by: Roy Steele on February 23, 2009, 10:55:00 PM
I also build selfbows and yes your right make the limbs been back into the handle more.Give  the whole bow a good sanding little more back toward the handle.You will lose a few pounds if not enough sand some more.
Title: Re: stacking/sanding?
Post by: George Tsoukalas on February 24, 2009, 04:16:00 AM
I don't see any pictures of the drawn bow. The easiest thing to do is make sure the bending starts at the end of the fades. Whip tillered bows stack. Trapping has nothing to do with stacking. 30 in is a lot of draw for a 62 in bow. I would have let the handle bend to decrease string angle. Yo could also reflex the last 6 inches but you've already pushed the limits.  Jawge
Title: Re: stacking/sanding?
Post by: John Scifres on February 24, 2009, 09:41:00 AM
You can't do it without losing a lot more than 3# draw weight I'd say.  That's not what I would call horrible stacking anyway.  

Keep in mind that stacking is a result of the loss of leverage that results from a string angle approaching 90 degrees.  

After 90 degrees, almost all the work you put into bending the bow is not adding anything to the work the spring can do.  In other words, stack weight is false weight.

In the end, you will be better off to retiller so that the inner limbs bend more.  This will decrease string angle and make your bow more efficient.  You will do so at the cost of draw weight, but it will be draw weight that is doing very little anyway.

Pictures would be very helpful.
Title: Re: stacking/sanding?
Post by: firewater100 on February 24, 2009, 03:28:00 PM
Here is a pick drawn to 28in.. not sure but it might be bending to much at the end of the fades.  Maby take some off mid limb? what do you all think?

 (http://i460.photobucket.com/albums/qq321/firewaterunlimited/bowdrawn.jpg)


scott
Title: Re: stacking/sanding?
Post by: John Scifres on February 24, 2009, 03:33:00 PM
That's nowhere near 90 degrees.  I'd leave it be.
Title: Re: stacking/sanding?
Post by: kennym on February 24, 2009, 08:57:00 PM
I think it looks good also!

John,that is a very good explanation of stacking!