# Advise: Knotty Cupped Top for Workbench



## mochoa (Oct 9, 2009)

Hello Lumberjocks,

I need advise on this top I acquired recently for FREE! I would like to use it for a future workbench project.

It is about 2 3/4" thick Red Oak. It is basically two slabs from the tree glued together side by side. It was made from green lumber against the cabinet shops advise to the client (a restaurant)

There are three problems:
-Since it was not dry it is very cupped. 
-Also, it is very knotty which would make periodic flattening of the bench top hard to do with hand planes. 
-Both slabs contain the pith of the tree which I think will make it very unstable and hard to keep flat

To overcome these issues I was going to let it dry, resaw it into maybe 4 pieces and re-glue and flatten. To overcome the periodic flattening issue I was thinking of gluing on a layer (maybe 3/4") of straight grained wood that would be easier to plane.

So, my question to you all is: Is this worth using for a bench top or is it more trouble than its worth? Would it serve me better for the legs and stretchers?

Thanks in advance!

Mauricio


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## donwilwol (May 16, 2011)

I think it would make a great bench top.

First, you didn't say how cupped it is. Its possible to pull it back "maybe". Early in the morning, on a sunny day, throw it on the wet grass cupped side down. I've never tried it with something this thick, but it may help.

The knots will make it harder to flatten, but also make it harder period, so you shouldn't need to flatten that often. As for periodic flattening. How often to you think you'll need to flatten it. Once every 25-30 years? That would be my guess for oak.

Resawing it and re-glueing would also work if you can't get it flat. If its got less than an 1/2" cup though, I'd flatten it.


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## crank49 (Apr 7, 2010)

Theres a jig in FWW to level that size slab using a router.

Is the whole top cupped or does each half of the slab have a cup. Looks like the latter in the picture, but hard to tell. If its one big cup all the way across then you would probably have to rip it down and re-glue.

Might be worth it to rip out the pith and replace those parts with better wood if you have to rip it any way.

I wouldn't worry about the knots if I could ever get it flat and re-glued and de-pithed. Would probably stay good a long time being oak.


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## mochoa (Oct 9, 2009)

Thanks so much for the advice guys.

Don, I know you have a chain saw mill and probably have a lot of experience with this kind of thing. P.S. I have a decrepit wooden jack plane I am restoring that I will post soon. I'm going to use it as a scrub plane.

The cup is about 3/8" so it may be better just to flatten as is. I wouldn't expect it to move much from there. I've heard of the wet grass trick before but have never tried it. Worth a shot, I wonder what will happen once it dries again.









Here is a pic of the pith, you can see it has already checked and had to be filled. This doesn't bother me esthetically. 









The other peculiarity with this situation is that it is finished on only one side (to let it dry the guys said). With that you would expect that it would dry/contract more on the unfinished side and cup in that direction but it didn't. I think this is due to the pith being off center in the board and being more to the unfinished side so there are more arching rings on one side that want to straighten out. Hope that makes sense, if not the pic shows what I'm talking about.

Crank, I know I have read something about the pith being bad news but I can't remember what specifically. If I can get this flat (with the router trick) do you think I can keep the pith? I've used the router jig on cutting boards it works great. The top is cupped about the same all the way down.

Don, I don't know how often I will have to flatten since my bench now is OSB, Sounds like I'm making too much of that? I like how it looks now but I'm assuming it is not done drying and may need to be flattened a little more down the road. Sounds like neither of you are into the "skinning with straight grained wood" idea. I do like to keep things simple but I'm just dreading having to do the router flattening process twice. It's a messy business. Planning it flat on the other had sounds enjoyable.

Don&Crank you guys both seem to suggest that Oak is a stable wood. I would have thought the opposite since it is so porous, I have about a 100bf of cupped oak boards in my garage. But once they're done cupping and you flatten them they stay relatively stable.

Thanks again for the advise and any additional input.


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## donwilwol (May 16, 2011)

Its hard to see in the pictures, but it almost looks like it was glued cupped. Is it actually flat from center to each edge?

Having seen the better pictures, (assuming the back side is the same, other than finish) I'd rip it right down the center, flip one side, joint it so its as flat as you can get it, reglue it, flatten as needed, which should be minimal.

If its not dry, I'd rip it and let it dry before re-glueing. (coat the raw edges)

Once oak is dry, oil it. Oil replaces water cells and hardens the wood. BLO would be my choice, unless you want to darken it, then go Danish oil first, then BLO.

I know I'm in a bit of a minority lately, but I think oak is a great wood. That will make a great bench in my opinion. My bet is, unless you going to mis-use that bench (and yes, I mis-use mine a lot) you'll probably never have to flatten it again, once its dry (assuming you keep it dry) and flat it'll stay that way.


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## LeeBarker (Aug 6, 2010)

I'd tackle this in a slightly different way that would involve no compromises concerning the "will it recup/will it not" question.

I'd rip it into 2 3/4" pieces, square them, then select the good sides and glue it up. It will be a beautiful, multi-colored butcher-blocky looking thing, hard as a foreclosure officer's heart, knotless on the top (luck being with you) and you can finish it any way you want.

If you had to make it wider because you lost some in the kerfs, a few strips of 4/4×2 3/4 (nominal) strategically placed walnut or mahogany will be stunning. You'll smile out loud every time you walk into your shop and see this work of yours.

My oh my. You have a find there, Mauricio.

Kindly,

Lee


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## donwilwol (May 16, 2011)

I can't disagree with Lee. That's another way to go about it. I like the look of knots though.


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## WDHLT15 (Aug 15, 2011)

Wood cups toward the bark. Seems counter intuitive, that is exactly what happened in your benchtop.


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## mochoa (Oct 9, 2009)

Thanks again for the input guys. I'm inclined to do as little cutting and gluing as possible and I do like the current look. I would just go ahead and flatten it as is but I don't want to lose 3/4" (3/8" on each side) of thickness.

Don I like the idea of flipping a side and regluing. It will keep the same look, I'll just have to do some check filling. The underside of the top is checked all the way down the length of the pith. I'm also with you on the BLO, I'm not planning on treating my bench like a piece of furniture. It will get well used so BLO will let me touch it up easily.

I agree with you about oak. It's a nice wood and hand plains well, I've done a few Oak projects and they look good if you choose the right grain and finish.

Lee, I don't think there is any way to turn the pith and make it look differently. If I had to rip it down to a few pieces I would probably need to replace the pith.

Here is a pic of the underside. 









Thanks again guys, I'll post the project when I finish it eventually. Now I need to find some big wood for legs and stretchers. I have a bunch of 4/4 oak I could use but gluing all that up would not be fun.


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## Bertha (Jan 10, 2011)

I would cover a 2×4 in chalk (the kind kidls like to write on sidewalks with). I'd scribe the surface, identifying the high spots. I'd hit those high spots aggressively with a scrub, and then get it close enough to put it through your planer or hit it with a Jack. I think I'd make a phenomenal benchtop, even with the additional work.


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## mochoa (Oct 9, 2009)

I like that chalk trick. I hadent heard of that one but have been trying to figure out how to do something like that. I happen to have a bunch of that chalk. Thanks!


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## mochoa (Oct 9, 2009)

And I just so happen to be finishing a restauration on an old wooden Jack that I'm gonna use as a scrub.


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## mochoa (Oct 9, 2009)

Question on wood movement. What if after I flattened this thing as is with knots and everything which I think looks cool, and then if I want to get it to about 3" thick I laminated some more red oak on to the bottom? would that be like veneering only one side of a board? would it seal in the moisture on one side and make the other side contract more as it dries?


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## Loren (May 30, 2008)

I think Lee has a good idea. My thought on the knots is that
the tissue in and around them will always be bucking up and
down on you if you have them on top - no matter how flat
you make it, those knots are likely to be proud when the 
humidity is low and shy when it is high.

I don't know what standard of precision you need from your
bench, but you'll struggle to make flat frames on a chronically
distorted bench.

One strategy would be to just flatten it and observe it and
see if you can do accurate work on it. If not, the top could
be laminated with a "skin" perhaps 3/4" thick. The knotty
board may not make a good work surface, but as a heavy
substrate I think it would be acceptable and certainly give
your bench some real mass.


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## Smitty_Cabinetshop (Mar 26, 2011)

Mauricio - Have you moved out on this yet? I would sure think about ripping this bad boy into four or five pieces then squaring those up prior to regluing. It'll cost you four kerfs in total depth of your bench, but should likely save more than a half inch of thickness… And they don't have to be equal pieces; I say that so you can avoid messing with the pithy parts of the boards. My .02. Good luck!


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## mochoa (Oct 9, 2009)

Thanks Loren and Smitty for the additional input.

Loren, do you think that "skinning" one side would cause uneven moisture exchange on either side of the top? I was thinking of doing it to the bottom but your making me think I should do it to the top.

Smitty, no I haven't done anything yet but its moving to the top of my project list soon so I'm in the design faze right now. I read Landis' book and now am reading Schwarz's book on Benches. I don't see any benches in Schwarz' book that are less than 3" thick which is making me think mine would be look too skinny. 
You raise a very interesting idea I hadn't thought of, the chunks don't have to be of equal size. I was trying to avoid as much lamination as possible but I think if I'm going to cut it up I might as well go with Lee's idea but cut it into 3" strips and flip them on end, I would just need to laminate more wood in to get it to 24" wide.

The other idea I was kicking around is to just cut this up and use it for leg and stretcher parts and figure something else out for the top. I just found a good source for 4×6 and 6×6 Southern Yellow Pine, kiln dried and pretty cheap but I really prefer the look of a hard wood to Pine.

Thanks again guys!


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## Smitty_Cabinetshop (Mar 26, 2011)

A 4×6, finished out to a leg, is a fine idea. 4×6s for the top too, for that matter. Make a nice leg vise chop out of your oak, and maybe mill it for planks of the bottom shelf. And for the deadman, if you include one. One complimentary wood to the yp bench. A thought…


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## Loren (May 30, 2008)

My bench is about 1.5" thick at its thinnest. I was made from a salvaged
restaurant butcher block 6' long by about 10" wide to which I glued
some cherry shorts, butting ends in a sort of bricklayer pattern to make
the top about 16" wide. Then I added skirts, a tool tray and dovetailed
walnut ends. The skirts are 4" wide.

The bench top really just needs to be flat either through planing
or torsion box or whatever. Then the base has to be the right
height for you and the whole thing needs to be heavy and solid
enough it doesn't shimmy when you plane boards on it.


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## mochoa (Oct 9, 2009)

My priority is simplicity and ease of build so I'm trying to do as little laminating and gluing as I can. 
I agree with what The Schwarz says that I would rather have a pine top made of 3 pieces than a maple top made of 25 pieces.

This is also due the fact I don't have a power jointer, it would take forever with my old wooden one. ;-)

Smitty, I was set on the look of the oak with maybe a walnut leg vise, would look sweet but I found a great deal on the pine. I found a place that will sell me 4×6" x 15' for $16 kiln dried. They have 6×6" cheap for legs too. I'm going to use a wooden screw so think I need big legs for the 2" whole I need to make in them. I like your thoughts on the accents. Oak accents would probably look better than Walnut, a more subtle contrast. I think the back and tan of oak and walnut would look sweet if I go that route.

Loren, I'm sure the top I have would work fine at 2.5" thick. My motives for the thick top are purely superficial, I just think a thick top looks cooler but I don't want to skirt it because that would interfere with clamps. Do you have any pictures of your bench?


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## donwilwol (May 16, 2011)

Mauricio, I don't understand your skirt statement. I have a 5" skirt and I would not want a bench without one. Is it something you've expirienced? I have the oposite opinion, which is ok, just wondering.


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## mochoa (Oct 9, 2009)

Hey Don, well I'm not talking from experience so I could be wrong. I just read that skirting the bench top to make it look thicker is not a good idea because it interferes with clamps if you wanted to clamp something to the bench top. Has this not been an issue for you?


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## mochoa (Oct 9, 2009)

Don. P.S. I just saw your bench project, it looks awesome. Do you like it? Is there anything you would change?


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## StumpyNubs (Sep 25, 2010)

I didn't have a chance to read all the comments, so sorry if this has already been said. But I would let it sit in the shop a few months and acclimate fully. Then fasten a couple boards to the sides as rails and make a jig to flatten it with a router. Clean up with a handplane and you're golden!


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## donwilwol (May 16, 2011)

Mauricio I love it. Last night just before I left the shop I gave it another quick coat of poly just to show it a little attention. As for the basic bench, there is nothing I would change. What I would change, and will change someday is the second regular vice (opposite the wilton) is a cheaper craftsman, that will get changed out for a leg vice. I'm hoping Smitty tires of his and want to sell it . Also the wilton is something I got at a flea market. Its a good vise but not a quick release. I sometime wish I'd waited for a quick release.

When you make the skirt make it about 5 inches wide (give or take per your preferences) and 4 inches deep. To me that would be the same as clamping to a 5" benchtop. If you are thinking of a bench skirt as a single 3/4 inch board then I agree, but with a 4" depth it adds weight, and is substantial enough to do anything.

The other nice thing, when I was planing on my blanket chest I could hook a clamp under the bench on the skirt and clamp the chest solid to the bench, so I was planing on a solid surface. Without a skirt I could not have done that.

A 1 1/2" top (similar to what stumpynubs and other have said) is plenty for a top, as long as you add a substantial skirt. Yes I'd like a 5" solid bench, but I didn't have the lumber for that. All the lumber in my bench was what I had at the time, and all I milled myself.


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## Loren (May 30, 2008)

Yeah, skirts aren't so great if you want to have a lot of clamp
flexibility. I tend to use Veritas wonder dogs and a holdfast
more than clamps on the bench and I also find handscrew 
clamps work pretty well with the skirts.

With a slab this thick I think you could "skin" one side with
some real lumber like 3/4" boards without it causing a lot
of weirdness. What I would do is mill a big sliding dovetail
at both ends on the underside of the bench and make 
some fat battens that dovetail into them to keep that 
slab flat.


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## Loren (May 30, 2008)

Here's a drawing of my bench without the tool tray and without the skirts.

This is from the back and remember, the tool tray and skirts are not
shown in this drawing.

You can see the grooves on the end of the top? They are for a 1/2" wide
spline and there is a mating slot for a spine routed into the end caps
of the skirt (not shown). It could also be done milling a short tenon on
the end of the slab. The important thing is to let the slab move in
width while the end caps are made with grain going perpendicular, so
they can't be glued.

The end assemblies are milled pine 4×4s and the legs are mortised into
the board on the bottom - perhaps it is called a trestle.

The stretchers are milled pine 2×10s and there is a 3/8" wide groove
cut into each edge. You can just make out the top grooves here. 
The joint is a bit joint pulled together by 4 long 1/4" threaded rods
running in those grooves, through holes in the legs, and snugged
up with bolts. It is very solid.


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## TCCcabinetmaker (Dec 14, 2011)

Ok, from what I can see…

Possible reasons for cupping. the unfinished side has absorbed more moisture causing it to expand, the finished side is not absorbing moisture, thus it isn't changing. As stated before, possibly clamped cupped, due to either un-even clamp preasure, or bad jointing.

A possible way to flatten this without hand planing or running through a machine is to sand off the finish on the finished side. Dampen the top of the finished side, Then attack the top to some strate thick braces underneath. If the first theory about how the top cupped is correct, then there shouldn't be a problem, just keep dampening the wood so that it will "stretch" flat. If it's the second theory, then the center joint may crack, but that also depends on what kind of glue was used.


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## bondogaposis (Dec 18, 2011)

I would resaw into 4" strips and glue it up so that the edges form the top. I'd keep the knots to the underside and lose the pith.


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## mochoa (Oct 9, 2009)

Don, your right a 4" deep skirt is a totally different story and actually gives you the best of both worlds as far as clamping. I guess without that skirt you couldn't get by without a board jack or a bench slave to hold up the other end of the panel. It will be a little tricky adding a leg vise if your leg is not flush with the edge of the bench top wont it?

Loren, I see what you're saying, the skirt doesn't let you clamp stuff to the top of the bench but it helps clamping things to the side, and with holdfasts and bench pups this is less of an issue.

I think I need to be a little cautious when reading Schwarz. He has a lot of absolute "rules" for what he considers essential in a workbench. It makes for simplicity and good read but there are other sides to the story.


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## RGtools (Feb 18, 2011)

Schwarz also debunks his own advice from time to time.

I think Lee has the right idea because you would be able to hide the effects within the bench where they won't bother you for years to come.

I also think Don is right when he said the board is glue cupped. Removing the joint might make a huge difference in the flatness.


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## Smitty_Cabinetshop (Mar 26, 2011)

I'd say this set of challenges is certainly getting solved, Mauricio! All that's left is for you to start cutting wood!


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## mochoa (Oct 9, 2009)

Smitty your right, everyone input was very helpful and I have a good idea of what to do if I decide to use this slab.

It's great to hear the variety of opinions and experiences from other people who have built their benches already.

I'm just very indecisive. I'm torn on whether to make this thing work or buy some SYP and start with a clean slate. 
•This thing has some issues, I need to chop it up and re-glue, maybe add in some additional wood to complete. Simplicity is important to me so I think I would just cut it right down the middle flatten and re-glue.
•It's a little short lengthwise. Its only 56", I need to add some end caps to stretch it to at least 6'.

If I envisioned my dream bench this slab wouldn't fit the plans.

But hey, I can always make two benches right!

Thanks again for everyones input


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## TCCcabinetmaker (Dec 14, 2011)

You're from Georgia, you oughta know better than Southern Yellow Pine for a work bench top. HEART pine is fine, but yellow isn't stable at all, despite what that guy who wrote some book says. (His table was actually heart pine anyways not what he was telling everyone else to use.)

And yes that is a small surface for a work bench. I'd look into maple, or something of the like for a workbench top.


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## mochoa (Oct 9, 2009)

TCCC, I'm actually from New Orleans, not a lot of Pine there but I hear you. Would it change your mind if I told you I found a place to by 4×6" Kiln Dried for cheap?


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## TCCcabinetmaker (Dec 14, 2011)

nope, Long leaf yellow pine (SYP) is basically fit just for framing, but only when there's no lodge pole available.


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## WDHLT15 (Aug 15, 2011)

What???


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## Smitty_Cabinetshop (Mar 26, 2011)

tcc feels pretty stong on this, fellas… He's not from the midwest, where every big box store and lumber yard sells construction grade, dimension SYP and every home uses it for, primarily, floor joists if it's not engineered flooring… He has his reasons, I'm sure. But, like you, never heard of 'lodgepole' before. Probably good stuff.


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## mochoa (Oct 9, 2009)

Ok, I was wrong, this thing is 66", and its 2 ¾" thick. I think that's not too shabby for a smaller workbench. This won't be my only work surface, it will be a dedicated hand tool work station.

So I looking at Roy Underhill's book again to see his work bench plans. All his benches, the same ones he uses on his show, are about 60" long and they seem to work for him. I always liked his little splayed leg Roubo that he makes with a 10"x3"x5' board. I think this slab will be perfect for that so that's what I'm going to do. No more indecisiveness. I have a plan and I'm moving forward.

The idea of having smaller workbenches to move around or put side by side etc. could end up being pretty versatile. And this one will be a little more mobile but still very heavy. I can put it on the back porch one day if I wanted.

So here is what I did last night. 

























The cool think about a board with the pith in the middle is that all the wood to side of the pith is Quarter Sawn! No cutting and flipping needed. All I had to do was cut out the piths. Next will be some minimal flattening, then re-glue the 4 resulting pieces for the top. It nets me out at about 18" wide before jointing, with the tool tray it will be perfect. I'm thinking of making the tool try bottom removable so I can get clamps on the back if I need to for clamping things to the top.

Now I just need to find some legs, or glue up a bunch of 4/4 together from my inventory.

Thanks guys for all your input.


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## mochoa (Oct 9, 2009)

P.S. I will be able to hid all of the knots by flipping a couple of boards!


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## Smitty_Cabinetshop (Mar 26, 2011)

Hey, I love it! Progress is a good thing, too!


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## donwilwol (May 16, 2011)

build man build!!!!


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## RGtools (Feb 18, 2011)

Beautiful. Sometimes the best course is just to stop questioning things and get down to business.

Can't wait to see how this turns out.


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## mochoa (Oct 9, 2009)

Hey guys, I've posted some pics of my progres here. Thanks again for all of your advise and input.


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