Author Topic: Knots in the back  (Read 828 times)

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Offline johnminnitt

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Knots in the back
« on: July 23, 2018, 06:58:08 am »
May I ask a question to the assembled bow-makers out there?
I have made quite a lot of longbows (ELB's), mostly laminated (due to cost/availability of wood), but a fair few self-yew as well, but I have a stave now with something I've not dealt with before.
The belly side is OK, a couple of knots but nothing unusual or very awkward, the sapwood is a bit thick so I may have to reduce it, but there are a couple of knots in the sapwood on the back, not gigantic but bigger than just a small pin ( a bit of severed twig sticking out of a small hole).
I was going to widen the back at that point, so that the fibres 'flowing' around the knot aren't severed, and maybe, if the sapwood is thinned, leave a little extra wood on the knot.
Has anyone done this, does it work, is there some other brilliant idea I haven't thought of, or would I be better just flattening the nocks and putting a rawhide back on?
'The crooked stick and the grey goose wing'

Offline Pat B

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Re: Knots in the back
« Reply #1 on: July 23, 2018, 08:36:09 am »
With that knot centered in the limb it should be OK as it is. Does it go straight through to the belly?
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline johnminnitt

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Re: Knots in the back
« Reply #2 on: July 23, 2018, 10:31:41 am »
Hello, thanks for the reply.
No it doesn't go through
There is another, less central (that doesn't go through either).
I'll try and do a [picture of the other one -
'The crooked stick and the grey goose wing'

Offline simson

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Re: Knots in the back
« Reply #3 on: July 23, 2018, 12:50:02 pm »
first you should try to get better pics (blurry)
second looking at the first pic: if that are pencil marks, that is no good idea. you should consider the tensile stress should spread continously on the back, will say you should leave extra wood on the sides at the knot area. Have a look on the grain and the wood will explain itself.
Simon
Bavaria, Germany

Offline johnminnitt

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Re: Knots in the back
« Reply #4 on: July 23, 2018, 01:56:19 pm »
Hello.
The straight pencil lines are the basic taper of the limb, the curved section is the extra wood left on the sides outside that, following the 'flow' of the grain around the knot.
Sorry about the blurry pictures, my very basic camera doesn't seem to work very well that close-up. I'll maybe have another try tomorrow.
'The crooked stick and the grey goose wing'

Offline Del the cat

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Re: Knots in the back
« Reply #5 on: July 24, 2018, 12:37:57 am »
Sorry about the blurry pictures, my very basic camera doesn't seem to work very well that close-up. I'll maybe have another try tomorrow.
If you put the bow right down on the background surface (say grass, cloth, carpet etc) the camera will focus better... you can see it is focused on the wooden surface in the back ground, so put the bow onto the background. Other tip is rotate the camera to get the focus sensor in line with the bow.
Del
Health warning, these posts may contain traces of nut.

Offline johnminnitt

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Re: Knots in the back
« Reply #6 on: July 24, 2018, 02:39:52 am »
Here follows an attempt at two better pictures.
Thanks for your interest gentlemen (and for photographic advice)
'The crooked stick and the grey goose wing'

Offline George Tsoukalas

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Re: Knots in the back
« Reply #7 on: July 24, 2018, 07:34:36 am »
Learning how to handle knots is a good skill to have for the bowyer. I think you did well with that one.

When tillering let the knotted area appear a little stiff in relation to the rest of the limb.

Jawge
Set Happens!
If you ain't breakin' you ain't makin!

Offline bitterman

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Re: Knots in the back
« Reply #8 on: July 24, 2018, 09:27:54 am »
I have no experience with knots (sory I'm new to this also) but that will sure look awesome! I love the look of the knots and the twists and crooks.. really gives a bow character!

Bruce