Techniques for dimensioning wood for laminated workbench top

[Marko Milisavljevic]

I have some nice 2"x8" douglas fir that I intend to rip in half and use to create laminated workbench top. I am looking for strategies for doing the work with least effort without a powered planer or a jointer.

The wood is, I guess, S4S in construction lumber terms - smooth surface with rounded corners. There is almost no observable twist or crook, little cupping, and some boards are slightly bowed - reasonable for 10ft boards. To get from here to a 24 x 72 x 3.5" laminated top, I am considering:

- using a circular saw with 8ft aluminum guide to rip 2x8s in middle, then use the same tool to "joint" the outside edges to bring all boards down to same width (3.5" or whatever I can get out of it) and get rid of rounded corners and any crook..
- planing smooth any obvious issues on gluing surfaces (like a splinter that will prevent two faces from fully seating against each other etc)
- gluing it (carefully, 2-3 boards at a time), hand planing for flat and square top. Relying on lamination to even out bowing - of course it won't work if all boards are bowed in the same direction, but assuming imperfections are random, it should hopefully even out. Any cupped boards will be flattened down to, say, under 1/32 out of flat across width. I probably won't use boards with any twist, but I think I may have none anyway.

...or do I have to take the much more labour intensive approach of dimensioning each piece carefully as if I were making a nice cabinet before gluing it together? Having never done a lamination, I have no idea how much I can rely on it to help me even things out, if at all.

Wood is kiln dried and has been in a heated shop at 45% for over a month now, still showing about the same moisture as when I got it - 13-15%.

Thanks for your wisdom.

[Jim Foster]

If it is construction lumber, my suggestion would be to dimension each board. I would also expect to get a finished top closer to 3" thick from 2x8 once all is said and done. I started with 2x12 and ended up with a top around 5" or slightly less, but my construction lumber had knots I tried to cull out whenever possible. I did a rough rip for each 2x12, then jointed and planed each side with power tools, then did a final edge jointing and sizing. I glued up 4 boards at a time (1 1/4" thick each) and then jointed and planed each glue-up before final glue-up. If I make another bench, I may be able to do it with less labor, but that's what I did as a first timer.

You might find your boards are better, mine were not pretty (green 2x12 fir) and were stickered for a year in my shop to dry. They moved enough when I did the initial rip to make edge jointing a required step, and the surfaces had too many factory planing marks to just glue up as is. For me, making the top was a misery, now that I made one and have a bench, I'd like to see if it's still as big of a job, so I may have one more bench in me.

[David Weaver]

As a hand tooler only 99% of the time, I would get the faces on those boards clean enough that you can glue them together. I don't know what you're using to plane the boards, but you can test the top face of each board and do your best to make sure they're all oriented in the same direction.

No need to joint the edges or anything, just the faces, and that shouldn't take long - just use a jointer with an aggressive setting for the chips (like a 4 thousandth chip maybe?, not too aggressive). Cut the 2x8s to length and joint the faces *before you rip the boards* (Don't overdo it with the jointing - you don't want to have to check that the faces are close to coplanar when you're done - i.e, don't joint plane them any more than you have to). Then plane an edge (with a smoother or whatever) only enough to tell which way the boards run, and then glue them together all running in that direction so you can cleanly plane the whole surface later without finding that some boards plane one direction and others another (that'll just create tearout issues if that occurs).

Do it either in one big piece, or in two separate glue-ups (in case the faces aren't as coplanar as you think) and then joint the two separate glue ups and then glue them together.

After everything is glued, then plane the surface of the bench (and bottom if you'd like if it's ratty, but no need to overdo the planing on the underside) flat with a jointer, using a coarser plane to start if it's out of whack (but with DF, you can probably just set the jointer deeper if you want to remove a lot of material).

That's a lot to digest, maybe, but it will take miles less time than finishing individual boards completely, and the quality of the result will be identical.

[Zach Dillinger]

I agree with everything David said, except that I would definitely rip the boards before flattening. This will require you to waste less thickness to get the board flat. Face the boards, don't edge joint them until they are glued, but try to keep them lined up as much as possible. Don't worry about flattening / jointing the bottom of the bench top; its a waste of time and effort. Just make sure that the areas where your legs will attach are flat and in one plane, a task easily accomplished with a chalk line.

[john brenton]

I did my bench by hand, and although maybe it's not the *correct* way, what I did was...

1. Joint the faces. Although you don't have to worry too much about the bends, and they can even be used to your advantage when clamping, the faces may be wavy. You might not even notice it until you glue up and have little gaps everywhere. So although it's a pain to plane all of that, it has to be done.

2. Rip the boards.

3. Check the grain direction of the edges and make sure to mark them. That's crucial.

4. I left the rounded edge on, and planed them off as I went. I don't have that many clamps so I had to clamp two at a time.

So with the boards glued, then planed, two at a time it was fairly easy to keep it relatively flat as I went.

I didn't have to plane the bottom too much as the table I was gluing it on kept it pretty close. But if I had it to do all over again, I would have planed the top and bottom, and took it to a cabinet shop drum sander before doing all the joinery. Having the bottom out of flat did make a difference, and with big legs and stretchers with no flex it does make that evident when you go to put it together.

[James Carmichael]

First, select 2x12s if available and select boards right out of the center of the tree and almost totally quarter-sawn. Use about the outer 3" from each side for the top for best stability. You can use the rest for legs.

Mark the high spots going across an along the grain. Use a jack going cross grain, 45-degrees to the grain, then a jointer along the grain.

[Jim Matthews]

Finewoodworking covered an interesting take on benchtop laminations (http://www.finewoodworking.com/PlansAndProjects/PlansAndProjectsPDF.aspx?id=33067)written by Garret Hack.

Each run covering the length of the bench is a lamination using three boards. This allows thinner, dimensioned stock to be used.
If the grain is alternated in the "stack" the layers can be immensely stiff. "Stiff as a board" as it were.

This technique was something of a revelation to me, as demonstrated in a Gary Knox Bennett video.
It's a truss, I suppose - forces are equalized and things stay flat this way.

Each stack of three boards has the center board shifted off center slightly, to create a pocket for easy assembly.
It's possible that these could be trued by hand before glue up, and further adjusted after things dry.

This allows you to work with face grain rather than edge grain.

[Prashun Patel]

I agree that you only need to joint the faces. However, I would rip them to rough width now and give them a little time to release any tension before jointing.

While it may take more time, I believe you will sweat less by gluing your laminations one or two at a time to the main slab.