BOW BUILDING HELP(TILLERING)

[stretch2]

I HAVE A QUESTION. I HAVE BUILT ABOUT 10 OR SO BOWS FROM RED OAK AND I THOUGHT I HAD DONE A GOOD JOB, AS A MATTER OF FACT I WON A BLUE RIBBON AT MY COUNTY FAIR THIS YEAR FROM ONE BUT THE LAST THREE BOWS I HAVE BUILT THE BOWS HAVE BEEN TO LIGHT IN THE 25LB RANGE. I HAVE NOT CHANGED THE WAY I HAVE BUILT THEM I STILL SO IT WITH HAND TOOLS A SHUREFORM RASP TO BE EXACT. HAS ANYONE ELSE HAD THIS PROBLEM. MAYBE IT COULD BE A MILLION DIFFERENT THINGS ANY INFO WOULD BE GREAT THANKS

[macbow]

There are a million variables as you said. Most of use when we started out had the same problem. One way to trick yourself is to build the bow longer than you wanted. Then you can cut it off to make it stronger.
By the way using all capital letters is considered shouting and is harder to read.
Ron

[Art B]

Paul Comstock wrote in his book "The Bent Stick": Good tapering produces good tillering.

So try to get a handle on good tapering of your limbs instead of tillering. Apply a taper to both limbs and let that in itself produce your tillered limb. From there it's pretty much just evening up your limb profile, and then from there reducing both limbs to your desired weight.

Learn to do that and you will seldom come in under weight. ART B.

[stretch2]

thanks for the info i will give it a try. also sorry about the all caps things. i am a drafting student and i am used to doing it that way for all my drawings cause that is the way you do it. i will do better

[Eric Krewson]

Do you have a tillering gizmo?

[Johan van Niekerk]

Art, are you refering to tapering thickness? Or width? or both?

[Art B]

Your taper can be thickness, width or a combination of both Johan. For example, a true pyramid design is side tapered only. No belly taper required. Rectangular/parallel design uses a belly taper only. A more common design (semi-pyramid) that I use a lot is a combination of the two because of material width restriction. Here I do some side and belly tapering.

Just remember to match you braced bow profile to which design you choose. A pyramid design will produce a arc of circle braced profile and a rectangular/parallel design will show an elliptical profile. A semi-pyramid somewhere in-between. ART B

[scrub-buster]

If you use the long tillering string too much you can come in under weight.  Try to go to a short string early on.  I don't know if this is your problem, but it is why my first bow came in too light.

[stretch2]

Eric i do have a tillering stick i use if that is a gizmo.

[Eric Krewson]

This is a gizmo, it tells you where to remove wood to get the limbs bending just right.

 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=001047

[003sim]

I love that gizmo, I made two of them which give you 4 different gizmo lengths I use in different areas of the bow. Wonderful invention, thanks for sharing that with everyone Eric.

[Mike Most]

I have a new 6 " gizmo, but am thinking I would like one in the 4" variety also.

Very Cool, thanks to one Eric......


Blessings

Mike

[hova]

i was pondering a double sided one as well , just mitering the ends to 45. and lopping the fine par of the edge off , so you have like a half 45 , half 90. ine side would be 2" , the other 4"....


-hov

[Roy Steele]

Use a scale on your tillering board.And slow down with your get to that point.