Surfacing Lumber

[Mark J Bachler]

I saw a thread on the MM board on surfacing lumber & wondered if anyone else was taught to 1<SUP>st</SUP> surface the convex face & edge instead of the concave face & edge. I was taught by an older woodworker to pick a spot in the center of the convex arc to start & joint it till the entire side is flat. As you joint the board the stress that caused the board to warp in the 1<SUP>st</SUP> place is relieved and the board will stay straight. I’ve actually seen boards straighten out more than the amount being taken off as the stress is relieved. Then of course plane to thickness & width. Any thoughts?

[John Miliunas]

Hey Mark, I'm no perfeshinull (can't even spell it! :rolleyes: ), but I see trying to joint the convex surface first as difficult, at best. How does one effectively keep it from rolling? :confused: I typically have my jointer bed set to take off, maybe a heavy 1/64th or a 32nd, at most. If the first pass of the convex part is at all skewed, I would think that the board would end up flat, but one edge thicker than the other. More passes through the planer, more work and possibly, more wasted material. :( Personally, if I'm working on something a bit more "special", I'll joint normally (concave down) and plane, but stop short of the final thickness by about a 32nd or better. Then I'll leave the board(s) "rest" for a couple days and do the final dimensioning when I'm ready to start final cuts, milling, etc.... Just MHO... :cool:

[Mike Cutler]

Mark. I've done it both ways. There is a technique that can be used to face joint a board with a planer. You make a sled and affix the material to the sled with the convex side up and begin to plane the material. I don't see that this is much different in principal than face the technique that you stated.It works really well if the material is too wide to properly face joint on a jointer.

[Mark J Bachler]

Hey Mark, I'm no perfeshinull (can't even spell it! :rolleyes: ), but I see trying to joint the convex surface first as difficult, at best. How does one effectively keep it from rolling? :confused: I typically have my jointer bed set to take off, maybe a heavy 1/64th or a 32nd, at most. If the first pass of the convex part is at all skewed, I would think that the board would end up flat, but one edge thicker than the other. More passes through the planer, more work and possibly, more wasted material. :( Personally, if I'm working on something a bit more "special", I'll joint normally (concave down) and plane, but stop short of the final thickness by about a 32nd or better. Then I'll leave the board(s) "rest" for a couple days and do the final dimensioning when I'm ready to start final cuts, milling, etc.... Just MHO... :cool:

Yep John I hear ya.
I don't joint like this all the time myself either but when I need something to stay straight I just sight down the board and try to keep both ends the same height off the jointer bed so you get a flat spot in the middle to start. Then just make the passes until its flat. I'll rarely do a face like this but I'll use the process on edges quite often. The board will actually pull itself straight as the material is removed. I know it goes against everything we learned in shop class but try it once & let me know what you think.

[John Miliunas]

Yep John I hear ya.
I don't joint like this all the time myself either but when I need something to stay straight I just sight down the board and try to keep both ends the same height off the jointer bed so you get a flat spot in the middle to start. Then just make the passes until its flat. I'll rarely do a face like this but I'll use the process on edges quite often. The board will actually pull itself straight as the material is removed. I know it goes against everything we learned in shop class but try it once & let me know what you think.

Hey Mark, I'm still a greenhorn at all this here sawdust making and am willing to try/learn just about anything! I'll give that a shot! I still have a bunch of semi-crappy Aspen, which I use for utility-type stuff and there are enough turns, twists, humps and lumps on it, to test out about *any* method! :D Why heck, if it's precipitating out there when I get home from work today, I might even give it a try then and let you know how it works out! Thanks for the tip/process! :cool:

[Jim Becker]

My concern would be the same as John's, but when you think about how a jointer works, any "roll" would eventually come out in your final passes over that face. Doing the other side first is jus' plain easier, IMHO, but the theory that Mark talks about is interesting! I'd love to know if it's indeed true.

[Bob Hovde]

My concern would be the same as John's, but when you think about how a jointer works, any "roll" would eventually come out in your final passes over that face. Doing the other side first is jus' plain easier, IMHO, but the theory that Mark talks about is interesting! I'd love to know if it's indeed true.


I don't know if it's true, but it was what I was taught in shop class back in the '50s. I've always done it that way, even it looked easier to turn it over and start by knocking off the corners. The board (if it's not TOO bent) does seem to straighten out faster than the cutting depth would indicate.

Bob

[Mike Circo]

Well I do Convex side down. Came to that conclusion strictly by trial and error.

With a relatively short bed (46") on my jointer, most boards will have an unsupported tail end when trying to joint or flatten with the concave side down. This causes a divot in the leading edge as it hits the knives at an acute angle, then it lifts up on the two ends of the concave shape and "bridges" the knives, then when the front edge drops off the end of the jointer it divots the trailing edge. (Bad description, but suffice to say, on a short jointer it plain doesn't achieve the desired result.)

By essentally balancing the convex edge on the bed of the jointer (like a bowl on a table) and pushing WITH PUSH BLOCKS on the low spot, I eventually thin the bottom of that bowl shape until the entire board eventually becomes flat and joints along its entire surface.

All I can say is that in my experience, with a little technique, I get better and more consistant results convex down on a small jointer.

[Tom LaRussa]

Hey Mark, I'm no perfeshinull (can't even spell it! :rolleyes: ), but I see trying to joint the convex surface first as difficult, at best. How does one effectively keep it from rolling? :confused:
How's this for a possible method?

Glue some shims onto the ends until the board more or less stays flat, i.e., until a line drawn between the warped ends sticking up into the air is horizontal. Then just joint the whole shebang as one piece.

[Chris Padilla]

Not a bad idea, Tom, but keep in mind that glue is tougher on cutters than the wood!

I would just nail the shims on!! :eek: :D j/k....

I think hot melt glue would be good here. You can do the same on a planer by building a sled and shimming where necessary. This time you won't be trimming off your shims.

[Bob Hovde]

If the board is really that bad, take your Festool and cut it into smaller pieces. Then it'll face-plane without having to go to down to thinner stock.

Bob

[Chris Padilla]

But Bob...what if it has some nice figure throughout!!??

Has anyone tried to resaw a bowed board? That might be a way to deal with it, too, and maintain some thickness.

[Tim Sproul]

Has anyone tried to resaw a bowed board?

Yes.

It isn't worth it. Go get a different board if you need something that long AND it needs to be flat.

[Dean Baumgartner]

Mark,
This won't work for face jointing but for a bad edge I have a long sled with toggle clamps on it then pretty much follow your method to take the convex off by sneaking up on it with the table saw.

FWIW.

Dean

[Mark J Bachler]

Jointed (6) rough oak 1 x 6's that were pretty warped last night. I did the faces 1st with the crown down, held both ends even off the bed so it made a flat spot in the middle of the arc. For every 32nd I took off, the ends dropped 3/32. Once flat I planed them to thickness. Then I cheated & straight line ripped them on the SW315 to 1/8" over finished width. Didn't have to joint the edges again so I planed them to finished width. I think jointing them with the crown up may save a pass or two on the jointer but I like to get that stress out of the board. (of course once I get them footballed to the counter top whats the difference?)