Author Topic: Is the early wood the weak link to cause set? (Read 45002 times)

Selfbowman · « **Reply #60 on:** January 19, 2021, 01:53:20 pm »

So if I cut a bow out of a straight grain stave and back it . Growth rings turned 90 degrees.

RyanY · « **Reply #61 on:** January 19, 2021, 02:00:30 pm »

The most scientific option would be to make a few slats of different grain orientation from that same stave (or any single board) and test them individually with bending tests. Building one bow won’t tell us much.

sleek · « **Reply #62 on:** January 19, 2021, 03:26:18 pm »

Quote from: Selfbowman on January 19, 2021, 01:53:20 pm

So if I cut a bow out of a straight grain stave and back it . Growth rings turned 90 degrees.

Yeah, thats the idea, but you shouldn't need to back it. And you would need to make it wider than normal as well due to the reduced surface area of the late growth taking compression and tension loads on the belly and back. So basically measure how wilde all the early growth rings are and subtract their total width from the bows actual width. If you make a 2 inch wide bow and those early rings add up to .25 inches, make the bow an extra .25" wide to accommodate it.

With your pyramid bows always having a solid ring on the back and belly, id be interested to see any difference made in cast and set with a bow made this way from you. Any losses due to the sheer forces on the early wood would be eliminated. Be an interesting experiment considering how consistent you are with your bows performance.

Selfbowman · « **Reply #63 on:** January 19, 2021, 03:51:50 pm »

Sleek the tapers on the pyramid where the growth changes won’t separate? That’s why I’m thinking a backing. I certainly don’t know what is being designed here. I think I can build it though. Don’t know if it will stay together though. Arvin

RyanY · « **Reply #64 on:** January 19, 2021, 04:28:07 pm »

Quote from: Selfbowman on January 19, 2021, 03:51:50 pm

Sleek the tapers on the pyramid where the growth changes won’t separate? That’s why I’m thinking a backing. I certainly don’t know what is being designed here. I think I can build it though. Don’t know if it will stay together though. Arvin

That’s the question in the other thread I started. For white woods, they almost never break along the early wood lines if the grain is straight, and often not even if it isn’t very straight.

Selfbowman · « **Reply #65 on:** January 19, 2021, 04:59:52 pm »

Ok selfbow it is . I like to make them more anyway. It will be a few days it’s wet here for the next few days . Probably next week

George Tsoukalas · « **Reply #66 on:** January 20, 2021, 08:03:46 am »

There are 3 types of board cuts. First there's plane or flat sawn where the butt grain looks like this =. Second there's rift sawn where the butt grain looks like this // and finally, there is 1/4 sawn where the butt grain looks like this ||.

So the first 2 allow for some grain run out ...maybe 2 per limb for a 50# bend in the handle bow. 1/4 sawn must have none at all. Something to keep in mind for this thread. If you cut a a 1/4 sawn slice out of stave seems like you'll get run outs.

My board bows over the years seem to take less set but I only like rift sawn boards. I don't keep records. This is anecdotal.

Jawge

Jawge

Selfbowman · « **Reply #67 on:** January 20, 2021, 08:53:14 am »

Jawge that was my concern. I don’t know anything about this I think I made one maybe two board bows in my life. Are you saying two ring run offs in one limb? I will try to find some scraps big enough to do a test. Arvin

RyanY · « **Reply #68 on:** January 20, 2021, 10:28:14 am »

Quote from: Selfbowman on January 20, 2021, 08:53:14 am

Jawge that was my concern. I don’t know anything about this I think I made one maybe two board bows in my life. Are you saying two ring run offs in one limb? I will try to find some scraps big enough to do a test. Arvin

I think Jawge is referring to runout from back to belly. If you planed down the wiggles in that stave, you would cut through fibers that could split regardless of early or late wood growth. I would try and carefully create a clean back following the forward and backward wiggles of the stave.

Selfbowman · « **Reply #69 on:** January 20, 2021, 11:16:42 am »

Ryan have you done this before? Just asking. And if so what was your results?

RyanY · « **Reply #70 on:** January 20, 2021, 11:25:44 am »

Quote from: Selfbowman on January 20, 2021, 11:16:42 am

Ryan have you done this before? Just asking. And if so what was your results?

I haven’t done this with a stave. Just a handful of board bows.

Selfbowman · « **Reply #71 on:** January 20, 2021, 11:36:27 am »

With good success? What kind of wood? A board comes from a tree how could it be different? Pics please if possible?

RyanY · « **Reply #72 on:** January 20, 2021, 12:33:41 pm »

Mostly red oak, hickory, and maple. I did a couple backed bows with maple backs and cherry and walnut bellies. Here's a full selfbow's. Red oak paddle recurve, poplar longbow, red oak bendy handle bow, and hickory longbow.