Author Topic: Tiller check please  (Read 560 times)

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Offline stuckinthemud

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Tiller check please
« on: July 05, 2020, 05:12:17 am »
Following the demise of the ash lath on my crossbow project here is the replacement apple lath, needs a bit of twist removing and a thorough tempering. On a string tight to the belly. One inch of reflex. 32inches ntn. Photos at brace height and half draw.



Offline Del the cat

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Re: Tiller check please
« Reply #1 on: July 05, 2020, 09:22:00 am »
Looking good.... so far... >:D
Del
Health warning, these posts may contain traces of nut.

Offline stuckinthemud

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Re: Tiller check please
« Reply #2 on: July 05, 2020, 11:00:12 am »
It's the "so-far" that worries me.  ;)  I've managed to perfect the last two into the bin after I reached this point........ >:D

Offline bownarra

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Re: Tiller check please
« Reply #3 on: July 05, 2020, 11:41:54 am »
Bending too much in the mid left limb and both outer limbs to the tips are stiff. You want an elliptical tiller on these. Least bend in the middle, with the amount of bend increasing as you progress along the limb towards the tips. Only a couple/3 inches at the very tips getting a wee bit stiffer.
Careful with the apple checking when heat treating.

Offline stuckinthemud

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Re: Tiller check please
« Reply #4 on: July 05, 2020, 12:47:55 pm »
So, do I soften everything to match the over-bend, match the over bend by softening  the right mid limb or just put up with it?

Offline stuckinthemud

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Re: Tiller check please
« Reply #5 on: July 06, 2020, 03:43:51 am »
Well This Sucks!  I strung the lath to full brace height for the first time and there was a huge limb imbalance,  both limbs bending evenly, one much more than the other. Spent an hour re tillering, everything looking really nice. Unstrung it, made a cuppa, came back 10 minutes later, restrung it to the same brace as before, massive limb imbalance is back as bad as before. NOT a hinge, the whole limb is bending nicely just SO much more than the other one, no obvious flaws, no grain run-out, dunno why but now I am a long way below target draw weight so it's on to mark 3.

Offline bownarra

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Re: Tiller check please
« Reply #6 on: July 07, 2020, 07:31:05 am »
You need to work the bow every time you remove wood. To make certain that your corrections have settled in. Freshly exposed wood has more compression resistance than 'bedded in' belly wood.