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reworking a warbow

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Del the cat:
IMO The reason that pin in WillS's picture caused a fret is because or the bark inclusion around the pin. The bark has no compression strength, so the pin is like having a hole in the bow... that's why I pick out any black manky bark stuff round the pin. The actual pin then often just falls out. I fill with either wood or wood dust epoxy mix.
Now't wrong with leaving a very slight bulge, but surely it's better to solve the problem than trying to cure the result of the problem.
I'd say look at the grain of the wood and follow that.
In your first pic, the extra thickness is IMO ludicrous. Bear in mind that stiffness is proportional to the cube of thickness.
Measuring from the pic the limb thickness to the left of the knot is 23mm and at the knot it's 30mm. That gives the knot a relative stiffness off more than twice the rest of the limb (comparing 23 cubed vs 30 cubed). That is self evidently bonkers and simply creates a relatively weak spot either side of the bulge inviting chrysals there. The whole bow should be in harmony, not a series of alternating stiff and weak points.
I think it's a matter of degree.
I'm not saying that leaving a little extra is "wrong".. but I'd suggest either a very little extra thickness or better, simply leave a tiny bit of extra width, (or leave the belly a bit less rounded at the pin) extra width has the advantage of increasing the amount of sapwood on the back, which is where the real problem is. Chrysals don't often cause bows to explode... weak points on the back do make 'em explode.
I've seen plenty of Warbows from plenty of big name bowyers and some have horrendous pinches alongside un-plugged pins.
You have to take which advice works for you.
I'd generally advise not shortening a heavy bow if you can avoid it... length is your friend as it reduces the stress.
All just my opinion of course, other opinions are also available, terms and conditions apply, contestants must be 18 years or over  ;)
Del

bershirebowmen:
Thanks Del, advice taken on board ;D
I see what you mean about it over stressing above and below, I had the similar bulge on my 140, and I think it made a weak point just under and maybe contributed to a sap wood splinter occuring 2 inches under(?) and the 8" above to the nock is curled over in a backward set, my main bow out of action :-\, thanks for advice, I'll have a ponder on what to do, 160@31 is too much for me, I'll have to have a think on what to do, I was thinking of shortening and narrowing the bow to avoid it looking like a fat flat bow if you know what I mean due to it being so wide, also i may of gone a little thin below the knot to even out the tiller, looks a little a skinny there now.I'm not fussed about the bowweight it comes out at I just want a functional reasonably heavy bow ( and being 5ft 6 inches with a 6ft 9 inch bow does come into it :)). Thanks for advice about making it wider around the knot, that was something I wished to question about as one of those two knots is quite close to the edge on the back, wasn'tsure what to do there if I narrowed it some.
berkofabowman

Del the cat:
It's slightly odd re-tillering a bow. You almost have to start from scratch. Reduce it to some sort of clean even taper, decide on a target weight and work towards that getting the tiller even being the first priority.
I'd say set yourself a definite target weight that is withing the amount of wood you have and your physical limit.
Don't worry about the bow being a bit wide, wide and thinner gives a better safety margin IMO.
Del

bershirebowmen:
Thanks Del, I'll give that a go, I wish I'd done that to start with instead of a quick fix attempt to sort it out, I may of lost a lot now compensating for that bulge, the string doesn't run parralel when strung, more gap towards the top limb at the handle, just hope I haven't buggered it totally, if I have I might be taking up golf  :-\

Del the cat:
You should have plenty to play with... better to have a well tillered 95# or 110# than a badly tillered 160# that is an accident waiting to happen.
Slow and steady wins the day.
Gotta remember the golden rule... when in doubt stop (and drink tea :)), and even when you are sure remove half as much as you think you should... ::)
It makes for slow tillering, but you get a decent bow ... eventually :laugh:
Del

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