limb compression fatal?

UnderControl16 · August 14, 2009, 02:35:00 PM

So i just finished tillering a 66" red oak long bow with a 20" handle... I was pulling it back a few times to full draw and then checked it over to see if it was ok and working. That's when i noticed about 20 little lines in a slight hingle on the lower limb due to compression. I have figured out how to prevent this in my future long bows :rolleyes: however, my question is, is this bow still shootable or will the lower limb explode/break on me? :( :confused:

Dano · August 14, 2009, 03:41:00 PM

20" handle?? on a 66" bow, and what's your draw length? This bow was doomed from the start, eventually it will just hinge right on over or self destruct in a very dramatic BOOM. Set this bow in a corner of your shop, the "corner of shame". How'd you prvent this on your latest bow?

George Tsoukalas · August 14, 2009, 06:34:00 PM

I suggest a bend in the handle design. Straight grained stock. There are buildalongs on my site. Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/

UnderControl16 · August 14, 2009, 07:57:00 PM

The handle is now 17" long actually and the lower limb has had those additional 2.5" added to it which has helped it already a lot and now i just have to get that part to bend better. draw length is 28" i believe. It's 55 pounds about. pictures to come shortly...

UnderControl16 · August 14, 2009, 08:03:00 PM

Dano · August 14, 2009, 08:03:00 PM

The handle only needs to be 8" max. 4" for handle 2" fades, the rest is a waste of wood on a selfbow.

UnderControl16 · August 14, 2009, 08:03:00 PM

I still have to work on the nocks, handle, and rest...

Dano · August 14, 2009, 08:07:00 PM

The handle only needs to be 8" max. 4" for handle 2" fades, the rest is a waste of wood on a selfbow. All the work is being done in mid-limb area, shotening the handle and fades would help but those crysals pretty much doom the bow.

UnderControl16 · August 14, 2009, 11:51:00 PM

really well ok then...

have to see what happens with this one and remember the lessons for the next one.

Hermann From Bavaria · August 15, 2009, 05:10:00 AM

in normal cases my handles are 10". that handle on your bow in gigantic. why you made it so big? hand shock suppressor?

George Tsoukalas · August 15, 2009, 09:45:00 AM

When I see chrysals that are localized to one area of the limb. That tells me the limb is not tillered well and is bending too much in that spot. When I see chrysals along the whole limb, as with yours, that tells me the design is off-the bow is too heavy or the lmbs too short or too narrow. You simply do not have enough limb for your draw length, undercontrol. If you want that long a handle you've got to make the bow longer. Yes, to answer your question, the bow will eventually fold up like a piece of paper. Jawge

George Tsoukalas · August 15, 2009, 09:45:00 AM

...and yes, I have had that happen. LOL. Jawge

Jesse Peltan · August 15, 2009, 02:57:00 PM

Your riser looks pretty thick. If I were you I would bring it down till you could get your hand all the way around it. That will make your fades smoother. That way you can shorten your fades and riser to get more working limb making the tiller less crucial. How far from the tips are the crysals?

Eric Krewson · August 16, 2009, 10:46:00 AM

I would be glad to send you a tillering gizmo. It will help a lot on tillering your future bows.

PM me if you are intrested.

UnderControl16 · August 18, 2009, 08:49:00 PM

Thanks Eric but like George said it was a flaw in the design and i will know have it fixed in the next one. I learn best through error usually and i finally learned. (this was the second one designed this way not to work) And i actually have made a gizmo from a while a ago when you first started putting them up on here.

And yes now i will only have 10" handles.

Actually Jesse the thickness is just about right for my hand once i shape it.

The crytals are about midlimb right now on the bottem limb. The bottem limb always bends (even before the crystals) more then the top so i will adjust next time.

The new design will be a 68-72" long bow (what i normally make) again from red oak (have good luck with it) with a 10" riser. Bottem limb - 32.5" Top limb - 29.5" Width at tips probably .6" with an additional layer there. About 2.5" high riser.

Jeremy · August 19, 2009, 08:19:00 AM

You're making the bottom limb longer than the top? That's a little odd. Everybow I've seen either has equal length limbs (possibly with the grip offset in the handle area, ie unequal length fades) or has the bottom limb shorter to aid in balance.

UnderControl16 · August 19, 2009, 10:02:00 AM

It just seems like the right thing to do since the two bows that i made like this have bent a ton more in the bottem limb then the top limb. We'll see who it goes, if nothing else a time to learn.

Jeremy · August 19, 2009, 10:44:00 AM

Taking excessive set on one limb is a result of overstressing that limb during tillering. Before bracing the bow for the first time you really need to get the limbs bending evenly on the longstring.

It's easiest for bowyers just starting out to make their limbs equal length and tiller dead even. Before shooting in you can introduce the positive tiller on the upper limb with a few more scrapes. It's a whole lot easier to get a proper even tiller when the limbs are the same length.

tecum-tha · August 21, 2009, 03:07:00 AM

Make the "investment" of "Traditional Bowyers Bible 1" or the "Bent Stick" and build bows that should work designwise from the beginning using the proven designs and layouts. You`re just wasting your wood (,money and time)for nothing....
Especially read the chapters about tillering!!!!
But to each his own....

UnderControl16 · August 22, 2009, 02:09:00 PM

My tillering was perfect on the other four self bows that i made but it's just these last two that i've been messed on. Ill be sure to post what happens after i do this next longbow and then i have to make a board bow for a friend too.