Author Topic: acceptable strapping/tiller advice  (Read 392 times)

0 Members and 1 Guest are viewing this topic.

Online stuckinthemud

  • Member
  • Posts: 1043
acceptable strapping/tiller advice
« on: October 11, 2017, 03:09:20 am »
Hi guys,
this longbow is currently 40# at 18" (bottom pic), I'd like it to draw to 28 (length is 73" ntn) but the handle is bending and trying to pop off the capping piece on the handle.  The cap is an 8" long piece of apple sapwood, rings are not violated, 3mm thick at its centre, feather-edge at the ends.  It was glued with 5 minute epoxy and 6 clamps, both sides were 'buttered'.  I've already had to cyano the ends and temporarily strap with cello-tape twisted and pulled very tight as they are lifting when the bow is drawn to 18".
low brace (3")


drawn to 18"


It very much looks like I will permanently need to strap the ends of the cap down; is this acceptable in the UK archery scene? If so, how would I do that? Presumably I still need the centres and outers of each limb to bend more to take the stress off the handle?

Offline Del the cat

  • Member
  • Posts: 6678
    • Derek Hutchison Native Wood Self Bows
Re: acceptable strapping/tiller advice
« Reply #1 on: October 11, 2017, 05:02:25 am »
If it's wrong now, it will be even more wrong at full draw.
IMO rasp it off flat and put on a longer thicker "Cap" that fades out to nothing, stuck with Resintite or some other decent glue.
It would seem the bow is bending too much at the centre so the only real answer is to add more wood to the centre (maybe a belly patch too?) or take it some off the belly at the outer limbs.
If you insist on wrapping it, I'd suggest linen thread which then has low viscosity CA on it to soak in.
Del
Health warning, these posts may contain traces of nut.

Online stuckinthemud

  • Member
  • Posts: 1043
Re: acceptable strapping/tiller advice
« Reply #2 on: October 11, 2017, 06:08:01 am »
A belly lam might be the better option, any idea on how long it might need to be?

Offline Del the cat

  • Member
  • Posts: 6678
    • Derek Hutchison Native Wood Self Bows
Re: acceptable strapping/tiller advice
« Reply #3 on: October 11, 2017, 07:36:00 am »
A belly lam might be the better option, any idea on how long it might need to be?
The problem is that in the pic the left limb looks thicker than the centre. It could just be an optical illusion (not the best pic and the shadow plays havoc!), but it looks like it goes thin from half way along the left limb all the way to the grip... I'd suggest getting some verniers on it and checking the thickness taper, aiming for about 2mm every 6"
I've marked in yellow where it looks thin to my eye... and I may well be wrong...
If you add a nice slat of say 4mm tapered down to say 2mm either end it should give you enough to play with, but more may be better, after all you can take it off easier than putting it on, but on the other hand you want some flexibility in the slat so that it will conform to the flattened belly and give a good glue line... and again it depends how much you need to take off to flatten the belly.
Del
« Last Edit: October 11, 2017, 07:50:10 am by Del the cat »
Health warning, these posts may contain traces of nut.

Online willie

  • Member
  • Posts: 1259
Re: acceptable strapping/tiller advice
« Reply #4 on: October 11, 2017, 09:21:27 am »
Stuck,
I like my tapers to be plus or minus .5 mm of design, Although I do see where some warbow guys like to side tiller more than others.

P.S. I read your thicknesses from the table in the other thread

Online stuckinthemud

  • Member
  • Posts: 1043
Re: acceptable strapping/tiller advice
« Reply #5 on: October 15, 2017, 09:49:20 am »
Thanks for the sage advice Del, I used some nice strong cascamite and an apple -wood lam, 12 " long across the centre of the bow. It needs a clean-up and a few adjustments, but its 35# at 24" and now it looks like this (drawn to 16").  More importantly, the bow just feels so much stiffer, much nicer to draw, not so 'hinged in the middle'

« Last Edit: October 15, 2017, 09:59:45 am by stuckinthemud »

Offline Del the cat

  • Member
  • Posts: 6678
    • Derek Hutchison Native Wood Self Bows
Re: acceptable strapping/tiller advice
« Reply #6 on: October 15, 2017, 09:56:29 am »
No prob' I'll put it on your account :o (to be claimed as a cup of tea, as and when I get over your neck of the woods)
Del  :)
Health warning, these posts may contain traces of nut.

Online stuckinthemud

  • Member
  • Posts: 1043
Re: acceptable strapping/tiller advice
« Reply #7 on: October 15, 2017, 10:01:18 am »
The kettle is always on, hot beverages served on the hour every hour ;D

mikekeswick

  • Guest
Re: acceptable strapping/tiller advice
« Reply #8 on: October 20, 2017, 11:10:59 pm »
Its still bending too much in the center and the mid limbs to tips are too stiff.
Throw that 5 min 'epoxy' in the bin it is next to useless! Certainly for lamination of working parts anyway. The best use for it is to mix with a little acetone - aka the MAssey finish.