Primitive Archer
Main Discussion Area => Bows => Topic started by: upstatenybowyer on February 22, 2018, 12:06:00 pm
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I'm assuming that cutting a backing strip from the outside of a tree would be ideal? If so, would it be a problem that the outside of a tree has an uneven surface, creating a strip with varying thickness?
Is it a better bet to go with a strip that is quarter-sawn, with growth rings running parallel down the strip? I'm guessing plain sawn strips would not be good.
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I would think the uneven thickness could be an issue. I'd personally go with the quarter sawn board backing.
Tattoo Dave
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1/4 sawn back and flat sawn belly is a deadly combo. I wont call it fail proof, but its dang close if you use the right recipe.
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Jeff...With laminated bows quarter sawn straight growth ring line backing strips are the best way to go.As you assumed.With bamboo backing strip I like quarter sawn belly also but not totally necessary if done with osage.
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just curious PD, is there something that make flat sawn better for the belly? (or quarter sawn less desirable?)
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willie are you me asking a redundant question so you can correct me later? Sure feels like it, considering your background and knowledge.
Personally. I like flat sawn bellies because the tools work nicer for me without waves or chatters. 1/4 on 1/4 works to, I think 1/4 on flat is easier.
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because the tools work nicer for me without waves or chatters.
thanks
are you me asking a redundant question......
not at all
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I cant prove anything I type with science or numbers. I just build piles of bows and spit out commonalities I find as I go.
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Flat sawn is fine for an appropriate specie, but you have to be at least as picky about the grain as you would with a board stave. Straight ring lines all the way down the face.
Quarter-sawn is definitely the best. The only problem is that if it came from a wiggly log, it can hide front to back run-out because the nice straight grain lines look so nice. That's pretty rare, but I've seen it.
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I'm planning on quarter sawing maple strips myself. I've got a ton of it. Sounds like that's the way to go. Does it make sense to cut them at about 1/4" thick and finish em off on the jointer?
I'd like to try splicing billets and backing them with the maple, like Marc does.
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Plane sawn, rift sawn, quarter sawn are all good for backings provided they are from a straight grained board. I haven't found any downsides to using plain sawn backings.
Quartersawn is the hardest to read for straightness of grain on the edge. The back with straight lines running length wise can trick you into assuming the edges are also straight. You need to look closely at the edges to see how straight the grain actually runs. Much easier to read the edge of a backing with rift or plain sawn slats.
Quarter sawn wood has a reputation for being the most stable, but I haven't noticed any difference once a backing is glued to a core/belly.
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Does it make sense to cut them at about 1/4" thick and finish em off on the jointer?
I don't care for jointing thin strips. If possible, I would joint the board, then cut the strip. One side will be ready for glue up, the other a sawcut finish.
joint the new sawcut on the board and cut the second, etc.
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I've read that a jointer or planer polishes the surface and the glue won't stick. You have to sand it anyway. No experience myself but just saying.
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DC, actually you bring up something that I was going to comment on in the band saw vs table saw thread. I have always heard that a clean cut is better for gluing than a sanded surface. Of course a surface polished by a dull blade is another matter.
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"If possible, I would joint the board, then cut the strip."
THIS IS THE RIGHT WAY.
" is there something that make flat sawn better for the belly?"
Willie, I know I'm not PD, but to me the answer is actually there in the TBB's. Q.S. backing shows both summer and winter rings, making them less dense than the other cuts. But, since almost all woods are stronger in tension than compression, even those "weak" in tension, Q.S. backs have enough, even plenty, of tensile strength, if they have the essentially perfect grain required.
On the belly, the opposite is true. Removing 10-20% of the density, elasticity, and strength of the belly by making it QS (exposing more winter wood) then IS harmful. You might not notice with something like ipe, but with a "lesser" ring-porous wood, say black locust, that'll count a little.
That's my thinking.
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I did a little surfing and it looks like for anything but epoxy an unsanded surface is best. But then I only surfed for ten minutes ;D ;D
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I'm planning on quarter sawing maple strips myself. I've got a ton of it. Sounds like that's the way to go. Does it make sense to cut them at about 1/4" thick and finish em off on the jointer?
I'd like to try splicing billets and backing them with the maple, like Marc does.
The only time I have cut a backing 1/4" thick was for a 100+ lb bow. I generally cut my backings no more than 3/16" thick and then thin them on my jointer. I also progressively thin them so that they are thinner towards the tips and I always sand both surfaces before gluing
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I'm planning on quarter sawing maple strips myself. I've got a ton of it. Sounds like that's the way to go. Does it make sense to cut them at about 1/4" thick and finish em off on the jointer?
I'd like to try splicing billets and backing them with the maple, like Marc does.
The only time I have cut a backing 1/4" thick was for a 100+ lb bow. I generally cut my backings no more than 3/16" thick and then thin them on my jointer. I also progressively thin them so that they are thinner towards the tips and I always sand both surfaces before gluing
Thanks Marc. This helps a lot. ;)
And thanks to all, I'm learning a ton on this one and on DC's as well.
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I build a sort of quickie laminate bow with a quarter sawn red oak back and a white ash belllly. I’ve done it with the white ash belly quarter sawn and riff sawn. The quarter sawn versions have better cast and are less prone to chrysal. I make them narrow and long (7/8” wide x 72” long) with a deep handle and keep them under 45lbs. They take a little set but not too bad and they are sweet smooth shooters. So my experience with ash would suggest to me that quarter sawn is better for belly wood. I once broke a riff sawn red oak back in tension with a lemonwood belly so i think quarter for the back is the way to go with tension strong woods.
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I would like to cut my own backings from 3’ sections of a tree say 5” in diameter at the small end. What would be the best way to break down the log to get quarter and rift sawn slats with no runoff? My mind keeps going on this direction.... Use stove a pipe straight log. Rip a line parallel to outside of the log from pith on small end to the butt end which would leave pith plus some. Then rip strips from that with the just sawn surface on table and crown up. That would yiel a combo of rift and quarter cuts, but would make a lot of waste I think. If any of y’all have a good breakdown method, I’d love to hear it.
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What would be the best way to break down the log to get....slats with no runoff?
do you wish to also eliminate the possibility of having spiral run-off in the board?
what species of log is it, BTW?
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Yes, I would like to have no runoff of grain. Wood will be hickory, elm, or hackberry. Those are what I have most readily available. I guess white oak is on the table too, but the deer sure like their acorns so I’d just as soon leave them be.
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if I wanted to also eliminate spiral grain, I would choose a log that has been split and shows no propeller twist.
spiral run out cannot be seen in a milled board, as with the wavy trunk/quartersawn thing mentioned earlier
not all woods split as easy as others though. perhaps someone that has spit those species that you mentioned can advise on selection. spiral grain can sometimes be seen in the bark, so a bit of eyeball practice might pay off so that you don't cut down trees needlessly, that said sometimes even a tree that does not show it in the bark, may well have prop twist.
once you have a twist free 1/2 or 1/4 log, you might have to glue a tapered ripping here or there so it lays flat on the saw table
what tool will you be trying to use to mill the log?
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Willie, the trees won’t be cut for backing, what I will use would be off cuts from stave logs or branch wood from the bigger trees. I had a hackberry stave that I intended to cut into backings because it split dead straight, but it’s a couple bows now lol. I will be using a delta 14” bandsaw. I used to own a Lucas swingblade sawmill. I wish I had that thing now. You could set it up to run parallel to the taper of the log and could quartersaw with it easier than any other mill.
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Flat sawn is fine for an appropriate specie, but you have to be at least as picky about the grain as you would with a board stave. Straight ring lines all the way down the face.
Quarter-sawn is definitely the best. The only problem is that if it came from a wiggly log, it can hide front to back run-out because the nice straight grain lines look so nice. That's pretty rare, but I've seen it.
Yep, has got me a time or two. Most of the time there is a slight chatter in the wood if you are planing, a drum sander can get you because everything is so smooth.
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Yep, has got me a time or two. Most of the time there is a slight chatter in the wood if you are planing, a drum sander can get you because everything is so smooth.
I was wondering if a hand plane would show it. If the grain is running out it should be smooth one way and ragged the other. If it planes the same both ways it should be good. Does that sound right?
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How about a backing made from the center slice of a pipe-straight sapling? Say, 2" in diameter? Technically that would be half sawn right?
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Saplings tend to have grown over knots.
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I wish I had that thing now. You could set it up to run parallel to the taper of the log and could quartersaw with it easier than any other mill.
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Saplings tend to have grown over knots.
Exactly. I take backings from the OUTSIDE of small elms occasionally, but the middle of small trees are full of the things left from when the tree was even smaller; knots, grain wiggles, branch roots, etc. I usually just get a couple out of a 2-3" tree, but if it was perfect, you might get 4 out of a 5" trunk, 1-1/2" wide or so. I wouldn't bother with the middle, though.
Small elms or ashes growing in shady thickets often have that almost perfect 3 inch x 3 foot section that is smooth and clean, but underneath it, who knows? The trick is to work them while green. I chainsaw them in half, thin them to about 1/4", then clamp them to a straight board to dry. Leave NO sunlight showing between backing and board, and clamp it snug and straight lengthwise. Then, when it's dry, you can mill the gluing surface better. The sides may wander a bit, but get the thickest part of the crown straight down the middle.
Two issues: When you clamp it, you have to make sure the crown doesn't end up wandering side to side. AND, you have to make sure it is really dry. If you glue up a backing even slightly green to a belly, it will continue to dry into un-manageble reflex. Trust me, that blank is still sitting in the corner of my garage.
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Great info. Thanks a bunch ya'll ;)