can't eliminate bow in quartersawn oak on the jointer

[Ken Klingman]

I am getting frustrated. I am trying to build an entry door and sidelites out of quartersawn oak. I've already built the frame and am reasonably happy with it. But I'm having a devil of a time getting the pieces milled for the stiles on the door & sidelites. I've got 6 boards of 4/4 quartersawn stock a little over 7' long. 2 were pretty much straight and I got very flat faces on them on my Hammer A3/31 jointer/planer. But the remaining 4 boards have about 1/4" bow over 7' and I can't seem to eliminate it for the life of me.

I'm running the boards through the jointer, trying to take a little off the face at both ends, leaving the middle concavity bowed with the bowed part down. Just like I was taught. But no matter how many passes I make I can't seem to eliminate the bow! I'm trying very hard not to bear down on the center of the board and only remove material from either end, but it's just not working. I believe my jointer is in good tune - I jointed and planed some hard rock maple this morning which also had a bad bow, but which came out perfectly.

The oak and the maple were both about 7' long, but the maple was only about 1 1/2" wide whereas the oak is about 6" wide.

I'm at my wits end and given the cost of this stuff I'm nervous as hell about ruining any more lumber!

Ken

[Wade Lippman]

I considered one of those a while back, but decided the tables were too short.

But I wonder what would happen if you took off a bit from either side and put it through a planer?

[Jerry Miner]

Jointing a 7' board on a 4' jointer is always a challenge. You're using 4/4 stock for an entry door?? Are you planning to face-glue two or three boards together, or ??? If you are face-gluing, then you can allow some bow in the boards at this stage and glue together concave-to-concave. Go ahead and apply a little pressure in the center. Do your final flattening after glue-up.

You ARE talking about bow, right, not crook or cup?

[Matt Day]

I would confirm your jointer is setup properly first. Sounds like your tables aren't coplaner.

[Ken Klingman]

Yes, bow. Not crook nor cup. And yes, I'm face-gluing 3 boards to get 2 1/4" thick boards (Wildland Urban Interface fire codes, don't get me started!). I did face glue 2 boards with slight bow for the jambs, but ended up with more bow than I'd like and not enough material left to remove more.

[Rod Sheridan]

Sounds like the knives are too high in relation to the outfeed table........Rod.

[Kevin Jenness]

I have had the best results flattening bowed planks by jointing with the convex side down. However, getting rid of a 1/4" bow over 7' in 4/4 is not likely to happen. Assuming the scenario is what Jerry Miner suggests, you may wind up with flat stiles if you put the flat boards in the center and oppose the bows on the outside faces, but no guarantees. I would suggest doing the glueup and letting the blanks sit for as long as you can before final flattening. Obviously, best prospects would ensue from gluing together flat planks. Which you don't have yet. Good luck.

On the other hand, if you are planning to make 6 stiles for the door and sidelights, use the flat pieces for the door and the bowed pieces for the sidelights. Except that 4/4 is not appropriate for an entry door. What are your projected finish thickness and widths, and how are you planning to achieve it with the stock on hand?

[Peter Quinn]

LOL, I hear you pain. Been there. Problem is...there is no problem. Its nearly impossible to flatten 4/4 material over that length and width to any usable thickness unless it is already flat. Using a short bed jointer wont help. My approach, take your flattest boards, use as the core. Oppose the other two layers, glue it up using I beams made from MDF or plywood as cauls. You can't just clamp 3 layers together and assume it will end up flat, you have to make some very stiff platens the length of your glue up to make that happen. I have some 1 3/4" stiles (QSWO) I glued up for a door on my house using 3 layers, still dead flat after 4 years. Yes, I'm a procrastinator. Shoe makers kids go barefoot. My boards never even saw a jointer. Plane them smooth, apply considerable pressure and force them straight with cauls......ends up flat. Or flatfish. Odd layers makes for good balance.

So don't fret, and don't focus too much on the jointing. All will be fine.

[John TenEyck]

Something sounds strange if you successfully jointed the maple stock but couldn't with the oak. Maybe the wider oak is so heavy that you are having a hard time keeping the lead and trailing edges tight to the outfeed table. For a 1/4" of bow I would joint only maybe a foot on both ends, then another pass for maybe 2 feet, and then maybe a complete pass. For those shorter passes, I always turn the board end for end so that I'm jointing the board as it goes into the jointer. You're going to lose at least 1/4" of thickness to get rid of 1/4" of bow, likely more. If your stock can't handle that much loss it might be best to get some more stock, as painful as that is. At least you could then use what you have now in shorter lengths and preserve more of it's thickness, maybe for the rails.

John

[Larry Feltner]

Have you considered using hand planes to remove most, if not all, of the bow, then do final straightening on the jointer? I think that is where I would head if I were struggling with getting the jointer to do the job.

[Kim Gibbens]

Is it possible to cut the piece in half and have a better chance of flattening it and use those two pieced as the middle layer of your three piece sandwich?

[Mel Fulks]

I agree with Kevin, it's possible the jointer needs adjustment ,but facing the convex side works better. You can prove this
by putting a straight edge on the concave side and measuring the gap. Then face on convex side and recheck, in many
cases the gap will be less ,in no case will the gap be more. You will find that with the way you have been facing ,the board is MOVING the wrong way and working against you. Just try it. My theory is the "standard " way is pushed for liability reasons. Face on convex side letting the end of board rest on out feed table, hold down on out feed table. Run again allowing the leading end to be cut. Go to planer and dress other side removing as little wood as possible; any additional pass should be on the side that you faced. There are a couple of old lengthy threads on this subject.

[lowell holmes]

I have ripped 2X8X7' walnut boards that were bowed into two halves. I glued and doweled the halves back together with the bowed halves cancelling the bow.

I was making a boardroom door. You could not see the glue joint and the boards were straight.

[john lawson]

Outfeed tale needs to be adjusted.

Take an hour or two, do a couple of google searches on how to adjust your outfeed table. (happens a lot when you change knives) Read your manual.

Good luck, you can fix it if you are patient

[roger wiegand]

I knock the high points down with a hand plane, then use the jointer to finish. I suspect the problem is that the board is too long for the jointer bed. You may well be better off jointing the convex side, purposely just taking passes in the middle of the board. Right now the board is just following its curve over the cutter. You'd need to lift the back end of the board to the same height as the front as it sits on the jointer at the start, and then reverse it as the board passes over the cutter to make progress with the concave side down. Not easy, hence going to the hand plane.