Tip failure

[DC]

Need some advice please. This is a Brazilian Walnut tip. This is the second BW tip I have had do this. Needless to say I won't use it any more and I will be changing the other one. It popped and peeled a strip of boo backing down about 6". I got the boo glued back down although it shows. Before I put on another tip do you think there is anything wrong with the tip size or design that I should change? The glob of glue in the pictures is from the boo repair.

PS I have been calling this Brazilian Walnut but I think it's actually Peruvian Walnut.

[PEARL DRUMS]

Hard to say by the pics, got any pre-break? I like my overlays to start 2" long. I use a lot of ipe overlays and have never had that happen.

[DC]

Just this one and it's too blurry to see much I think. You jogged my memory when you said Ipe. This was sold to me as Braz walnut(Ipe) but I found out later that there is a good possibility that it's Peruvian Walnut. Whole different beast. With 2" overlays do you put the nock out toward the end?

[John Scifres]

Here's a Tipalong of sorts I did about a million years ago.  I know this is antler but it shows how I do tip overlays.  The only failure I have had is with mesquite with squirelly grain.  It looked about like yours when it broke.  I think you are on the right track in questioning the material.

http://web.archive.org/web/20070704141039/http://residents.bowhunting.net/sticknstring/hbbb3.html

[PEARL DRUMS]

I make the groove stay within the bows core and not past it. That creates leverage, no bueno'.

[DC]

OK, longer, I can do that. I don't have antler but I have horn/hoof. I'll do that. Thanks guys

[wizardgoat]

I prefer small overlays, and I only use horn. I've broken an overlay or 2, but only from dropping my tip.

[DC]

How long is small, Ryan?

[Josh B]

It's hard to tell from the pic, but it looks like you might have had a bit of a square edge in the bottom of the string groove.  If so that is nearly always a recipe for failure.  It's important to make sure the groove has a smooth radius a little bit larger than the diameter of the string.  No square or sharp edges anywhere the string will contact and proper grain orientation are key to the overlays holding up.  It looks like your grain orientation was adequate, so that probably wasn't the culprit.  It also helps to use a wood with interlocking grain for overlays, just for added durability.  I'm working on overlays right now so I snapped a few pics showing how I eliminate all sharp edges that will let the string get a bite on.  Josh

[DC]

Thanks GD  I'm pretty sure it was rounded and smooth but I will take a close look at the replacements.

[Eric Krewson]

Pretty sure your problem was from the wood overlay failing first. I had that happen when I tried edge grain wood for overlays. I now use the toughest wood I have for overlays, which is burl wood, this stuff is like iron.

I make my overlays 2 1/4" long and graceful.



One time I had one fail from what appeared to be a bad glue job by me. One side became unglued and chipped off which put too much strain on the glued side which split it off along with 8" of the back of one limb.

I threw my failure bow into a corner for years but just got around to fixing it with a radical overlay a few months ago. Shoots great.

[DC]

All fixed The string in the second picture is the string saver.

[John Scifres]

Very pretty.

[mwosborn]

That one looks nice DC.  I would agree that the walnut gave causing the failure.  Had two (on the same bow) black walnut overlays fail on a FG bow.  I concluded it was a combination of the wood and the wrong angle on groove.

[PatM]

Peruvian Walnut really is Walnut and it doesn't have the strength to work as a reliable overlay.