Author Topic: Grain orientation on stave  (Read 26886 times)

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Ruddy Darter

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Grain orientation on stave
« on: March 27, 2017, 05:45:27 am »
Just started my very first yew stave (Oregon), and discovered a kink in the end grain of the bottom limb, (had to saw off 9" due to a central split in the sapwood and now left with 77").
I reckon this kink runs throughout most of the bottom limb as I run off down the side chasing what I thought was the central grain, which was rather confusing. The top limb's end grain is more regular looking and didn't have a problem chasing the centre.
Just wondering if I should follow this grain for the belly profile to avoid set and for better limb action, or not bother about it.
Here's a pic, one with normal profile and one I'm contemplating which I think might work better.
Thanks for any advice,
 
 R.D.
« Last Edit: March 27, 2017, 05:53:28 am by Ruddy Darter »

Offline Del the cat

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Re: Grain orientation on stave
« Reply #1 on: March 27, 2017, 09:11:48 am »
Simply ignore it... :)
It's irrelevant on the belly, and on the back it would mere;y leave you maybe a long thin island along the length of the bow worst case.
Not a problem, it may simply give you a cool looking slightly concave back... sweet  :)
E.G.
A stave with a bit of sideways waggle can just be laid out straight as long as you watch out for edge tools digging in and following the grain.
If it's really worrying you, just jog the bow towards one edge of the stave. The thin off cut from the other side may even make a kids bow or a miniature  :) As per pic... excuse wobbly cross sections  :-[ , but I'm sure you get the idea.
Don't fall into the trap of trying to cut 2 staves... Treat it as one good one plus an offcut that may or may not be useful.
Del
« Last Edit: March 27, 2017, 09:19:30 am by Del the cat »
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Ruddy Darter

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Re: Grain orientation on stave
« Reply #2 on: March 27, 2017, 09:29:09 am »
Right you are Del, OK, I may keep it central then and  I may go for the right hand side that you circled, a little bit closer to the centre though. Thanks, that's really helpful 8). I'll only be going for one bow, ain't got a bandsaw to try for it anyway, and I've taken off 3 sides a fair bit at the handle. I'll be steaming in recurve too after mostly tillered, it has a fair amount of d-flex.
Pic 2 is a rough and exaggerated idea for steam heat bending, a shallow but sharp bend at the centre first, then recurve the limb tips. Seem reasonable? (it will only be drawing to 31")

 
Many thanks again,
 R.D.
« Last Edit: March 27, 2017, 09:52:51 am by Ruddy Darter »

Offline Del the cat

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Re: Grain orientation on stave
« Reply #3 on: March 27, 2017, 10:08:14 am »
Remember the old addage, keep it simple, a bit of natural deflex is your friend duting early tillering. Then like you say once it's looking reasonable put in some gentle recurve.
I wouldn't try to put any bend in the centre 'cos the bow is thickest and stiffest there... much easy to bend the tips. (Seriously trust me trying to put much bend in the middle can take a lot of effort)
Just recurve the tips to get 'em back in line with the back of the grip plus maybe an extra inch (that may pull out after).
If your steam bends pull out, switch to dry heat and take plenty of time so it sets the bend in and heat treats it a tad.
Del
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Ruddy Darter

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Re: Grain orientation on stave
« Reply #4 on: March 27, 2017, 01:20:59 pm »
Cool beans Del, that makes good sense and shall do,  8)
Taken some more wood off chasing the belly ring down and glad I did as I'm getting a lot better picture of the growth direction and what will be dead centre, a lot was deceiving by being sawn clean, the growth rings are pretty tight so got me a little confused but I've hollowed out the ring/rings I'm chasing with my curved carving gouges which are making light work of it.  :), glad I decided to give them a try.
 
 R.D.
« Last Edit: March 27, 2017, 01:28:56 pm by Ruddy Darter »

Offline Del the cat

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Re: Grain orientation on stave
« Reply #5 on: March 27, 2017, 02:09:33 pm »
Still not sure why you are chasing rings on the belly ???? :o
Del
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Ruddy Darter

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Re: Grain orientation on stave
« Reply #6 on: March 27, 2017, 02:16:45 pm »
So I can accurately define the centre of the exposed ring/rings( where I've stepped it a few rings while working to the handle to allow a safety margin of a little more wood before working to nearer dimensions)  and then mark out my measurements for final bow and take off from the sides accurately and evenly in accordance to where the bow snakes a little. Because the rings are tight I break into them when working flat I don't know if I'm sloping off left or right and the back is rather rounded which adds to my confusion, you would probably see it for what it is straight away Del but for me  Its just making a clearer picture for me to start with rather than a load of grain lines that would confuse me, until I can read them better from experience I think this is helpful to me. When I cut through that peak on the grain all I'm left with is a load of lines and not knowing which ones the centre and run off the side coz that's the only one showing a flat opening grain.
 I can now draw a line in the centre of the valley down the length of the bow knowing I have the true centre and measure off from there for the sides. I hope there is method in my madness and I'm making sense, sorry if I'm not. (before I started doing this I didn't know if I was coming or going :-\)
 R.D.
« Last Edit: March 27, 2017, 04:33:54 pm by Ruddy Darter »

Offline WillS

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Re: Grain orientation on stave
« Reply #7 on: March 27, 2017, 04:42:50 pm »
You don't need to follow grain with Pacific yew.  You could cut a bow out of a stave diagonally and it wouldn't matter.  Ignore the lines, the grain, the direction.  Mark a straight line, draw the bow out and cut it out. 

Pacific yew is brilliant for that reason - even a crazy C-shaped bent stave you can just fit a straight bow down the middle somewhere and not worry.

Ruddy Darter

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Re: Grain orientation on stave
« Reply #8 on: March 27, 2017, 04:46:19 pm »
Thanks Wills, but to start with I'll continue doing this, good practice if I work on other woods,  It feels correct for me to do this to get the optimum from the wood, I may be wasting my time but it feels right.
But thanks all the same, that's good to know,  8)

*I was once told it's always better to have the bow orientated the way the tree grew, i.e top of the tree is the top limb, root end of tree is bottom limb, therfore after looking at the stave closer I've been working what will be the top limb* (I don't know how much this applies to Oregon yew, but I'll work it that way.)
 R.D.
« Last Edit: March 27, 2017, 06:11:45 pm by Ruddy Darter »

Offline Marc St Louis

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Re: Grain orientation on stave
« Reply #9 on: March 27, 2017, 07:03:04 pm »
I assume you are making a warbow, none the less I would orient the bow so that the back has a more or less convex back rather than concave.
Home of heat-treating, Corbeil, On.  Canada

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Ruddy Darter

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Re: Grain orientation on stave
« Reply #10 on: March 27, 2017, 07:33:38 pm »
Yes Marc, a warbow is the goal. Right OK I see what you mean. Thank you.

 R.D.
« Last Edit: March 27, 2017, 08:11:58 pm by Ruddy Darter »

Offline WillS

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Re: Grain orientation on stave
« Reply #11 on: March 28, 2017, 04:20:01 am »

*I was once told it's always better to have the bow orientated the way the tree grew, i.e top of the tree is the top limb, root end of tree is bottom limb, therfore after looking at the stave closer I've been working what will be the top limb* (I don't know how much this applies to Oregon yew, but I'll work it that way.)
 R.D.

I remember when he told me that as well  ;)

It's daft, by the way. 

Ruddy Darter

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Re: Grain orientation on stave
« Reply #12 on: March 28, 2017, 05:34:29 am »
OK thanks Wills, and is that the general consensus from most bowyers concerning all self warbows? (meant politely, be nice to read other views concerning this, just for the fact when I'm removing wood from bottom of stave to top it comes of cleanly, in the other direction it tends to mostly tear out due to the wood being a little denser bottom heading north, just thinking on a finished bow with the bottom limb being a little shorter building the bow same as it grew would possibly add some safety or better longevity, especially for the heavy weight bows, and with the majority of staves, mainly European, they are not perfectly clean with the major knots being towards the top, so if a bow fails its better that it breaks high and not around the groin and legs area. (?))
Thinking out loud really...
 
 R.D.
« Last Edit: March 28, 2017, 05:45:33 am by Ruddy Darter »

Offline WillS

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Re: Grain orientation on stave
« Reply #13 on: March 28, 2017, 06:42:10 am »
To be honest, what you'll find is that once it's on the tiller everything will change.  It's nice going in with a plan, but it's wood and human error having a party, so it will never work out perfectly.

Shape the bow, get the tapers even and the balance point central, get it bending and choose the stiffer limb as the bottom of the bow.  It'll possibly even change as you work it, and you'll flip it a number of times.

Ruddy Darter

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Re: Grain orientation on stave
« Reply #14 on: March 28, 2017, 07:12:58 am »
Cool Wills. Yes, absolutely...intent is perfect, but it's human to error ;), I'm just going with it. I'm enjoying what I'm doing although some may see it as not needed, but it's giving me a clearer picture and confidence. Getting to know the picture of the grain while removing it is valuable to me I feel, as well as practice removing wood efficiently accurately with minimal dust.
I'll shut up now and work when I can on the stave instead  :D
Thanks and a pic of the stave.
« Last Edit: March 28, 2017, 08:07:31 am by Ruddy Darter »