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Main Boards => The Bowyer's Bench => Topic started by: costa_ct on July 24, 2013, 03:00:00 AM

Title: Bow center and arrow shelf height
Post by: costa_ct on July 24, 2013, 03:00:00 AM
Hi guys!

I've just finished my first one piece recurve and already laminated the second one.
One big problem for me is that it seems to be a real "cartilage destroyer".

It's a 58" NTN fiberglass with ash lams, 22" riser, 56# @ 28", 1/2" positive tiller.

I established the center of bow in the center of the riser, making there the groove for the upper point of my grip and cut the arrow shelf 1" above.

I'm sure there is a mistake in this design but I cannot figure what is it.

I want to continue with the second bow but I need your advice first.
Title: Re: Bow center and arrow shelf height
Post by: Bowjunkie on July 24, 2013, 04:45:00 AM
What do you mean exactly by... "making there the groove for the upper point of my grip"?

How do you hold the bow and string? Split finger or 3 under? Even pressure on the grip? Or high or low pressure?

Unless further explanation of "making there the groove for the upper point of my grip" drastically alters what I THINK you mean, it sounds to me like your bottom limb is much too strong compared to your top, limb timing is way off, and that's what you're feeling.
Title: Re: Bow center and arrow shelf height
Post by: MoeM on July 24, 2013, 05:11:00 AM
1/2" is way too much difference in my opinion- 12mm; I go for 2-3mm usually.
The pressurepoint I usually place 2" above center with straight or classic LB grips (palm presses) and 1" above when I do a pistolstylegrip so that the deepest point is in center and thumb-hand palm(?) presses.
Title: Re: Bow center and arrow shelf height
Post by: costa_ct on July 24, 2013, 08:19:00 AM
First, sorry for my poor English!

By "the groove for the upper point of my grip" I meant the deepest point of the riser. The pressure point is somewhere between the center of may palm and my thumb (I suppose).

It should have been a pistol grip but I'm afraid it decided to be a sort of hybrid.
And I intended to make this bow for 3 figers under.
  (http://i1237.photobucket.com/albums/ff468/ArrowsMaker/1strecurveriser_zps69f812ed.png) (http://s1237.photobucket.com/user/ArrowsMaker/media/1strecurveriser_zps69f812ed.png.html)

Sorry, MoeM, but I'm afraid I didn't understand you very well, you mean Presure point 2" above the physical center of the bow? Meaning... for my 58" NTN the presure point should be at 27" from the upper nock?
Title: Re: Bow center and arrow shelf height
Post by: MoeM on July 24, 2013, 08:40:00 AM
No, in other words; pressurepoint always in the middle but a straight grip has pressure in the middle so for 4" griplenght shelf got to be 2" above center while a deep grip has it`s pressurepoint between upper 3/4;4/4 so grip goes 3" below to 1" above.
Hope this makes more sense...
I recently did a grip like your`s also 50:50 and it works but I prefer the other way.
Title: Re: Bow center and arrow shelf height
Post by: Dan Bonner on July 24, 2013, 12:12:00 PM
Sounds like way too much positive tiller. I would try to cut it down to 1/8-1/4" and remove as much mass from the limb tips as possible.

Bonner
Title: Re: Bow center and arrow shelf height
Post by: costa_ct on July 25, 2013, 11:48:00 AM
Thank you all guys for trying to help me.
Unfortunately I've already removed as much as possible but I only managed to reduce the "plus" of tiller from 3/4 to 1/2".

I know that my lack of experience is to blame and that I cannot do anything to make this bow be a hunting one.
I only try to understand what mistakes I made, in order to avoid them in the future.

So, what I've learnt is that I have to cut the arrow shelf 1" above my thumb for a deep grip and that the positive tiller has to be 4 to 6 milimeters.

One more question! Is there any difference between 1 3/4" and 2" width? I know the second is wider  :)  but I mean ... is there any advantage in using one or another?