Thinning tips - how much more?

[Tommy D]

These are the tips on a “static recurve” I attempted with Kerfs in Ipe and a bamboo back. They give the bow a lovely shape but I suspect that because I couldn’t bend them sharp enough they aren’t doing much for performance - but maybe I am wrong. Bow has about 2 inches of reflex unbraced. I was about to finish the bow but had been playing with another and compared tips and realised I had gone much thinner on my other bow.

How much more could I take off? It is a hunting bow for a friend so I don’t want tips to snap off at the risk of a few extra fps but I reckon I could probably slim them a bit?

[Weylin]

I don't think that would be a static recurve. I'm pretty sure those outer limbs will be working to some extent. There's nothing wrong with that, it's just a different design. The proportions on those tips look fine to me based on the picture. I'd say if the tiller looks good and you like the way it's shooting then leave it. There is not enough material to take off out there that is going to realistically change the fps. Having a bit of reflex like that can boost the performance noticeably. I think the bow has a nice looking side profile. shoot it and enjoy it.

[DC]

I think it looks fine, especially for a bow that may get some rough use. I just finished a Molle and I made the levers as thin and narrow as I dared. They are 7/16"wide and 9/16" thick about 6" from the tips. The last little thinning didn't make more than 1fps difference and now it gives me the willies to brace it. It just feels fragile even though I know it's OK.

[Del the cat]

I don't think that would be a static recurve. I'm pretty sure those outer limbs will be working to some extent. There's nothing wrong with that, it's just a different design. The proportions on those tips look fine to me based on the picture. I'd say if the tiller looks good and you like the way it's shooting then leave it. There is not enough material to take off out there that is going to realistically change the fps. Having a bit of reflex like that can boost the performance noticeably. I think the bow has a nice looking side profile. shoot it and enjoy it.

+1
IMO it's too late to slim them anyway, as I'd suggest they should be narrower, but probably only if left a tad thicker.
Del

[Tommy D]

OK thanks everyone. That answers that. I find it quite hard to actually finish a bow. Most of them linger in a semi-finished state of limbo their whole lives! I can’t decide if it’s cos I hate sanding or I don’t like closing chapters! My favourite sinew backed Osage has been “unfinished” for 10 years - just in case I wanted to “tweak” it! ! But I want to put this one in the post!

Out of interest has anyone actually broken a tip off by drawing/ shooting the bow? Rather than stepping on it/ slamming in car door etc?

My hunch is they could theoretically be much thinner than one thinks  - I guess this is a question for the flight bow makers. In boats many of the innovations and material strength testing comes from the guys pushing boats to the limits for speed/ racing - I believe some of them are pretty much made as one use hulls for single races - with very fine margins - sometimes too fine! But you wouldn’t want to go sailing round the world in one! I guess flight bows are the racing yachts and hunting bows are the cruising yachts of the archery world!

[bownarra]

You can go scary narrow (1/4") but for the bows useage I'd leave them alone.

[DC]

I guess flight bows are the racing yachts and hunting bows are the cruising yachts of the archery world!

One of my favourite definitions is "Cruising is going to exotic locations to fix your boat"