Bowed lumber

Hi, Is there any way to straighten bowed lumber? By bowed I mean the board curves off to the left or right as you sight down its length. I have a large amount of 5/4 by 4 inch cedar trim boards for the house I am building. Most of these have become so badly bowed as to be unusable.

I thought about attaching a straight-edge and machining them straight on the table saw, but I think they'd end up only being maybe two inches wide at the most.

Thanks for any help!

-Tony-

Reply to
Tony Jester
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Not much can be done to straighten it other than muscling it into place and holding with fasteners. If they're long enough, you could halve them and then machine them straight - you'll have more width that way, but shorter lengths to work with.

Reply to
Fly-by-Night CC

I don't quite understand what you mean. Could you explain? They are long lengths - 16-20 feet. Thanks!

-Tony-

Reply to
Tony Jester

IIUC the board would sit more or less flat on the floor. If that is the case the bending is called 'crook'. Bow is in the other plane so that the board would rock or be arched when on the floor.

Yes, but that is probably what you'll have to do.

If you cut them into short lengths then joint them you'll get more board feet of usable lumber--but all short pieces. Should be OK if you're building bird houses or mailboxes or some such.

You can also google the thread on cooking salmon on cedar planks...

Reply to
fredfighter

I've never actually tried this, so maybe some of the other guys should comment on whether or not it makes sense.

What about ripping right down the middle, then edge-gluing the curved surfaces together? It might be a bit of fiddly work getting the two curves to line up, but it seems like a pair of templates and a router should work for that.

That way you'd end up with a full-length board--although the grain would be a bit odd.

Chris

Reply to
Chris Friesen

What Steve and Fredfighter said.

Reply to
Fly-by-Night CC

What might work would be to use one half for the template, have them spaced just a bit closer together than the size of pattern bit you have, then raise one up so the bearing runs against it and the bit cuts the lower one to match.

Reply to
Frank Campbell

That's a brilliant idea. Since most people don't have a circular plane it would probably be easiest to smooth the convex curve and then use it for the template.

Chris

Reply to
Chris Friesen

If this is exterior trim and the lengths are long I'd be inclined to nail it in place while bending it into place... Cedar is relatively soft and easy to straighten out while nailing up... I'm assuming of course you aren't talking about wood so crocked that the ends touch!

John

Reply to
John Grossbohlin

I'm no expert, but if you can wet wood to bend it, why not wet it to straiten it?

I'd try to make a jig to hold the pieces firmly that allows the pieces to be straiten by applying counter pressure to the bend area, keep a sprinkler going on the wood, after several hours you'd be able to determine if it actually works.????

Reply to
Roger Bigras

OK, crook. Funny I never knew that. Must be where crooked comes from :-)

What about placing two board side-by-side on pipe clamps with the crook in opposite directions and gluing with polyurethane glue? Will it hold?

-Tony-

Reply to
Tony Jester

Not really a good idea Tony. You have no idea - and no control over which of the two is exerting more force in the curve, so rather quickly you could find yourself with a crooked laminate. As well, while glued joints are strong you really don't want to introduce stresses like that into a glue up. You'd be far better off to rip a straight edge on each of the two pieces and glue that edge up. After that you could rip the whole thing again to true up the two outer edges.

Reply to
Mike Marlow

Yea, that's what I figured. Thanks for saving me the experiment.

-Tony-

Reply to
Tony Jester

I did that once; wet the board and recurved it for a couple days to let it dry. It took out about half the curve, but a few days later it was back where it started.

It turned out to be a bad news/good news joke. The bad news it that it didn't go back to it's original shape until after I used it. The good news is that the curve turned out to be a nice design note; now I claim to have done it on purpose.

Reply to
Toller

There you go. Use it for the trim over an arched doorway.

Reply to
fredfighter

Thanks for the good info.

Reply to
Roger Bigras

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