Trad Gang

Main Boards => The Bowyer's Bench => Topic started by: Texas Trad on October 18, 2011, 03:23:00 PM

Title: I-beam risers
Post by: Texas Trad on October 18, 2011, 03:23:00 PM

I have a question for the Bowyers. When building a 1 pc. recurve, using a I-beam const. riser, if the center piece (.050 glass) is off set so that it will not show in the shelf window, will this cause any problems in the fadeouts allowing the limbs to torque when drawn?

Title: Re: I-beam risers
Post by: JamesV on October 18, 2011, 03:46:00 PM

That is a very interesting question. I would think if there were any flex in the riser or twisting caused by the I beam being off center it would be minimal at best. Any twist in the riser upon drawing the bow would have to be transfered to the limbs.

Title: Re: I-beam risers
Post by: Jason Scott on October 18, 2011, 03:53:00 PM

Haven’t tried that but I doubt it would. Feather those tips really well. If you use a power lam you wouldn't have any torque issues. Consider doing that.

Title: Re: I-beam risers
Post by: Trux Turning on October 18, 2011, 11:29:00 PM

No you won't have any issues with the I-beam off set like that.

Title: Re: I-beam risers
Post by: Texas Trad on October 19, 2011, 10:17:00 AM

Thanks guy's, I havent built any bows since 07, and am ready to get started agian.

Title: Re: I-beam risers
Post by: Sixby on October 21, 2011, 10:31:00 PM

I use a power lam when I do that just for safety sake.

God bless you, Steve

Title: Re: I-beam risers
Post by: Texas Trad on October 22, 2011, 11:07:00 AM

Thanks Sixby, I am still studying the power lam, I am assuming it is to change the working length of the limbs.

Title: Re: I-beam risers
Post by: Sixby on October 22, 2011, 04:08:00 PM

The power lam simply moves the working area towards the outer part of the limb. The part of the limb with the power lam is still a working part of the limb it just does not bend as much and takes some of the pressure off of the fades. It helps to eliminate overbending at the fades and smooths the drawn limb profile out significantly when done correctly. It is not necessary to extend it far past the fades , a couple of inches will help bunches.
 
As to whether it shortens the working area of the limb depends a lot on the design of the individual limb. In a recurve for instance it may just cause the tips to open up a bit more , change where the limb is working. or if you use sufficient tip stiffnere or geometry it may cause the outer portion of the limb to work a bit more. I would say that rather than shorten the working area it more like proportions it.
God bless you all, Steve

Title: Re: I-beam risers
Post by: Texas Trad on October 23, 2011, 01:40:00 PM

Thanks Sixby, that is some very helpful info. This is one of the things I like most about this site and Traditional archery in general, peoples willingness to help others.

Thanks Again
Mark