Woodworking Talk banner

1 - 10 of 10 Posts

·
Registered
Joined
·
129 Posts
Discussion Starter #1
So, I've got a 2x8x8 that I just bought from the lumber store a week ago. I've already glued two of these together with relative success. They make the rails for my new pine workbench. This is the last glue step for me, so I'm really looking forward to getting it done. From here on out, it's all mortise and tenon work, which I'm really looking forward to.

Anyway, I get the third piece out to do some planing in prep for glue up, and I realize it won't lay flat on my bench. Awkward. It's bowed upward in the middle by about a half an inch.

I finished the top of my workbench months ago, so it's fully functional on two metal sawhorses, which is nice.

The mating board is not bowed, so I expect there to be quite a bit of bow in the final rail if I use this board. I'm not sure if that will be a problem or not.

Is there an easy or recommended way to approach this problem, or should I just go buy another board? They're pretty cheap, but it's hard to find a board that long without some kind of defect at a lumber yard.

Clamps while planing, maybe?
 

·
Sawdust Creator
Joined
·
8,047 Posts
A jointer would be the proper tool, however to remove that much of a bow, you'll lose a lot of material. I'd try clamping and gluing....or go buy new lumber.
 

·
Registered
Joined
·
1,530 Posts
I'd probably get a new board. Here's why: (See the last paragraph for the reason I said "probably")

If the top is bowed up half an inch, you're going to lose at least a full inch of thickness in flattening it. First, you'll lay it with the convex side up (as it is). You'll need to remove at least half an inch to bring the middle down level with the ends.

Then, you'll lay it with the concave side up: if you planed the convex side correctly, it will lay flat and solid on the workbench. Now you'll have a concave cross section along the length of the board, with the ends half an inch higher than the middle. So, you'll need to plane off half an inch from each end, to bring them down level with the middle.

Your board is now at least an inch thinner than it was when you started, you've worked up a good sweat, and you need to go buy a new board anyway because this one is too thin.

The reason for the probably: If you're dovetailing this in, or pegging it in place, or something like that, you could try forcing the bow out with clamps first. It might work. It might shatter. It might appear to work, then disintegrate later on, when you're least expecting it. If I didn't want to (or couldn't) spend the money replacing it, I'd force it and hope for the best. Given the option, though, I'd replace it: I don't like trying to force anything thicker than 3/4" pine into place.
 

·
amateur
Joined
·
235 Posts
Do not under any circumstances use a bowed or twisted stretcher with the thought/hope that the weight of the top or compression will flatten it or straighten it. It won't and in fact it will telegraph onto the finished base and cause a wobble. At least that was my experience.

How do I know? A 200-250 pound top of 5 inch LVL/Hard Maple on my workbench didn't cure the wobble that was caused by a twisted stretcher I used by mistake. The stretcher was 4 inches of laminated 2x material

I guess that your 2x material is dimensional lumber from the Borg or similar retailer? If so, just start over -- it is inexpensive enough.

One thing, 2x material just loves to twist, bow and warp. It needs to adequately dry before you use it.

Good luck.

Greg
 

·
Registered
Joined
·
911 Posts
The board may still be useful if you have any small parts to make, otherwise if you've not cut into it you may be able to exchange it at the big box store.
 

·
Registered
Joined
·
129 Posts
Discussion Starter #7
That's what I thought. Thanks. I'll go buy another board.

To answer the other question, I've got a 4.5" smoothing, a jack, and an 8" jointer plane. I find I use the jointer for just about everything. I barely ever touch the other two. I do use the smoothing plane for surface finishing though.
 

·
Old School
Joined
·
24,027 Posts
A few thoughts. When you plane or joint a board, you could release some inner stresses, causing it to go out of whack. If your lumber was good to go before any milling, maybe just straight edging would be the minimal to do to get a glue up.

I found the longer the lumber is, the better it usually is (possibly more select). I would just get another board. Instead of looking at eight footers, the tens might be much better.






.
 
1 - 10 of 10 Posts
Top