Primitive Archer

Main Discussion Area => Bows => Topic started by: Lucasade on September 20, 2016, 02:24:58 am

Title: Marking out centreline
Post by: Lucasade on September 20, 2016, 02:24:58 am
I usually use the centre pith line as the centre when marking out the width on my bows, as I like the way the resulting bow follows the meanders of the wood. However if I do that with this stave I'm suspect that this kink will certainly not look good and may weaken the bow:

(http://i1266.photobucket.com/albums/jj535/lucasade2/image_zpsgt4tldsk.jpeg)

(http://i1266.photobucket.com/albums/jj535/lucasade2/image_zpswayurmx2.jpeg)

Would it hurt to just take an average line through here or will the knots either side that cause the kink also cause me trouble?

Thank you for your help as always.
Title: Re: Marking out centreline
Post by: stuckinthemud on September 20, 2016, 03:19:51 am
How near the tip is it? An average line might lead to run-out, personally I'd leave it a lot too wide when roughing it out and see what happens when you thickness it - kinks and knots can change radically when you get near the outside of a stave, sometimes they even disappear altogether
Title: Re: Marking out centreline
Post by: Lucasade on September 20, 2016, 03:57:37 am
It's about a foot from the tip - on the left as you look at the photo is a huge knot sticking out of the side of the stave, on the right (inside of the kink) is a much smaller one but some goes out the side and another bit goes straight up through the back.
Title: Re: Marking out centreline
Post by: FilipT on September 20, 2016, 06:22:41 am
What wood is that?
Title: Re: Marking out centreline
Post by: Lucasade on September 20, 2016, 06:24:48 am
Laburnum.
Title: Re: Marking out centreline
Post by: SLIMBOB on September 20, 2016, 07:29:08 am
Follow perfectly.  Anything less will weaken it.
Title: Re: Marking out centreline
Post by: George Tsoukalas on September 20, 2016, 08:19:55 am
You should always follow those vertical, lateral grain lines on lay out. If you don't, you may weaken the bow. Jawge
Title: Re: Marking out centreline
Post by: Lucasade on September 20, 2016, 10:26:43 am
Follow the centre it is then! I guessed that would be the answer but wanted to be sure. Hopefully it won't create too much of a dog leg...
Title: Re: Marking out centreline
Post by: ajooter on September 20, 2016, 09:51:55 pm
I always lay my bows out from the belly side.  I usually do progressive thickness tapers and refine my centerline as I go.  This way the growth rings are always centered nicely within the limb.  It's probably just inexperience but I always have trouble laying out a bow from the back.
Title: Re: Marking out centreline
Post by: Lucasade on September 21, 2016, 01:52:59 pm
I've never tried laying out from the back - I read in Del's blog that the pith makes a good centreline and it's easier to measure parallel to it with all the nice lines going out to the egde to guide you!
Title: Re: Marking out centreline
Post by: bradsmith2010 on September 21, 2016, 02:13:03 pm
sometimes there is no pith,, follow the kink,,  you will violate the grain if you dont,, :)
Title: Re: Marking out centreline
Post by: George Tsoukalas on September 21, 2016, 03:27:09 pm
Following the pith sounds ok but what do you do if there is none?
If you look closely you will see those lines that run tip to tip.
http://traditionalarchery101.com/layout.html
Jawge
Title: Re: Marking out centreline
Post by: Lucasade on September 22, 2016, 03:26:48 pm
That's how I usually lay it out - I just haven't had a stave with such a dog leg in it before and wondered if I could get away with it! It's all marked out now and I'll take my billhook to it when I get a chance.
Title: Re: Marking out centreline
Post by: George Tsoukalas on September 22, 2016, 05:17:43 pm
Leave the nocks a good 1 inch wide and the handle full width at least until you string it in case the string does not track on the handle well. Then, we can talk about tracking so you may not have to heat it. Jawge