Trad Gang

Main Boards => The Bowyer's Bench => Topic started by: Nicon on August 27, 2012, 11:34:00 AM

Title: Second glass RD build.
Post by: Nicon on August 27, 2012, 11:34:00 AM
Hello.

This is my second try at a glass bow.
66" 44# @ 28"
Black glass, maple core and oak riser.
Right limb in the pictures is the top limb with 0,16" positive tiller. Riser fadeout on the top limb was bit thick and the transition on the belly side isn't very smooth. (Hope it makes sense. My English isn't good enough to explain it...) It feels like a sharp hinge on the belly side but it's smooth on the back. Could it become a problem? Glue line at the fadeout is perfect.
Tiller looks the same as in my previous bow.  http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=008389;p=1#000000  But the bad riser fadeout makes it look like a sharp hinge.
No twist this time!    :thumbsup:  

How does the tiller look?
  (http://nicon.planet.ee/vibu/refdef2_01b.jpg)
  (http://nicon.planet.ee/vibu/refdef2_02b.jpg)
  (http://nicon.planet.ee/vibu/refdef2_03b.jpg)
  (http://nicon.planet.ee/vibu/refdef2_04b.jpg)
  (http://nicon.planet.ee/vibu/refdef3.gif)  

Gert
Title: Re: Second glass RD build.
Post by: rmorris on August 27, 2012, 12:39:00 PM
I got a longbow design that has nearly identical characteristics to your bow... I have often looked at that "hinge" just after the fade out and shook my head... but after over several thousand shots I have not had any problems...I will tell ya, it sure makes a fast smooth bow... I will try to post some pictures later...
Title: Re: Second glass RD build.
Post by: Glunt on August 27, 2012, 02:38:00 PM
Nice!  What taper rate did you use?  Tiller looks good to my eye. Looks like you are great on string angle at full draw. So, you could probably go with a little more taper, which would would reduce the bend at the fades and still keep your string angle under 90 deg at full draw.  That said, how it shoots is what matters.  Post up finished pics when its done!
Title: Re: Second glass RD build.
Post by: jess stuart on August 27, 2012, 02:49:00 PM
Looks like you nailed it.
Title: Re: Second glass RD build.
Post by: Swissbow on August 27, 2012, 06:11:00 PM
Tiller looks nice to me. You could increase the taper or add a p-lam to move the bend away from the fades. Or you could modify the profile a bit and add some deflex right at the fades of the riser to make the transition from the riser to the limbs smoother.

----------
Andy
Title: Re: Second glass RD build.
Post by: Nicon on August 28, 2012, 03:23:00 AM
Thanks for the confidence boost, guys!
I was hoping that i didn't have to mess with the tiller anymore. Narrowing the tips didn't seem have much effect and i didn't want to make the tips too narrow.
i used 0.002" per 1" tapered lam. Limb with tapers from 1,5 at the fades to 0.55 at the nocks. It's not a straight taper because i have been narrowing the tips.

On the next bow i would like to try all parallel lams. I have plenty of parallel lams and no more tapered. How should i design the limb on a all parallel bow? How thick and long should the power lam be? Can laminate it from thin veneers? I have some black walnut veneers and it could look interesting between maple limbs.

Profile is 1" deflex and 3" reflex. Should i go to 2" or 3" deflex?
Title: Re: Second glass RD build.
Post by: rmorris on August 28, 2012, 11:06:00 PM
Here is my similar bow, it is amazing how close they are. I am currently using a .002 taper but I think I may step it up to .003 or .004

(http://i1229.photobucket.com/albums/ee465/buckskinbows/876E88D3-D905-4D8E-A120-B94A8F9AE6FF-3597-0000074F3E680B4B.jpg)

(http://i1229.photobucket.com/albums/ee465/buckskinbows/7676E692-786C-4F14-A6F8-EBCD44F7075B-3597-0000074F454A333C.jpg)

(http://i1229.photobucket.com/albums/ee465/buckskinbows/726D4321-194F-4D48-86ED-7F0DC460BE85-3597-0000074F4C295C1D.jpg)
Title: Re: Second glass RD build.
Post by: JamesV on September 03, 2012, 06:03:00 PM
On that type of bow I use a .0035 to .005 taper and start the taper 2" from the fades. That helps eliminate the hinge at the fades and gives a more uniform bending of the limbs.

James
Title: Re: Second glass RD build.
Post by: Living_waters on September 05, 2012, 01:06:00 PM
Just a question...... If you taper the ends of the riser block out an extra 2 inches super thin would it not work the same way? Reason I asked, I was wondering if I done it by a dumb mistake. Short bow (54") I made last winter does not have the hinge in full draw profile.    (http://i126.photobucket.com/albums/p86/2manydogs_photos/Mobile%20Uploads/Photo0512.jpg)

BTW your tiller looks good
Title: Re: Second glass RD build.
Post by: Living_waters on September 05, 2012, 01:13:00 PM
Ralph your tiller looks just like every other RD bow I have built. They may not be quite as smooth but they are fast, maybe faster.
Title: Re: Second glass RD build.
Post by: Nicon on September 10, 2012, 04:53:00 AM
Pictures of the finished bows. Both of them could use a refinish. But since they are both keepers and first of many to come, I'm gonna keep them as they are.

Second bow(black glass) ended up being 41#@28" Shot about 60 arrows from it and I'm loving it!
The other bow is 35#@28" I think I messed up the tips and made them too skinny. Bottom is ok but the top one is half the with of the pencil where the string rests...

  (http://nicon.planet.ee/vibu/bows_01.jpg)
  (http://nicon.planet.ee/vibu/bows_brace_01.jpg)
  (http://nicon.planet.ee/vibu/bow2_fulldraw_01.jpg)
  (http://nicon.planet.ee/vibu/bow1_fulldraw_01.jpg)
  (http://nicon.planet.ee/vibu/bow2_handle_01.jpg)
  (http://nicon.planet.ee/vibu/bow2_tips_01.jpg)
  (http://nicon.planet.ee/vibu/bow1_handle_01.jpg)
  (http://nicon.planet.ee/vibu/bow1_tips_01.jpg)