A Flat-out Bad Time

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I know that my recent blog entries have been lightweight at best – thanks to Jeff Burks for picking up my slack. I’m determined to finish writing this “Campaign Furniture” book by Dec. 31, and so all my energy is going into the laptop.

And the benchtop.

Today I’m finishing up the collapsible bookcase – the last (I hope) project for the book – and none of the boards were behaving when I planed them. That usually means something is out of kilter – the plane’s sole or the benchtop. It was, of course, the benchtop. This bench is the one I built during the French Oak Roubo Projects in Georgia this summer. Until recently, the benchtop was settling in gently.

During the last two weeks, things got ugly. The benchtop itself has shrunk more than 1/16” in thickness – and shrunk even more near the dog holes and planing stop. This is, of course, totally expected because the holes expose more end grain to the atmosphere.

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My benchtop after two passes with a jointer plane.

That doesn’t bother me. What’s distressing is the glue joint has opened up a 1/32” at the surface of the benchtop for almost 24”. The opening isn’t deep – less than 1/4” – but it looks like a gaping maw when I think about everything I did to get that seam airtight while gluing the benchtop.

It is what it is. Chances are it won’t fall to pieces.

But I have to get the top flat tonight so I can finish up this bookcase before the snow arrives. (It’s no fun to spray shellac in a snowstorm.)

— Christopher Schwarz

About lostartpress

Publisher of woodworking books and DVDs specializing in hand tool techniques.
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25 Responses to A Flat-out Bad Time

  1. jonathanszczepanski says:

    You can always fill up that gap with some epoxy. I’ve heard the only thing that could throw that asunder is a crazed Carolinian swinging a maul… but how often does one run into one of those really.

  2. “It is what it is”. Man, I’ve said that a lot lately.

  3. rondennis303 says:

    Question #1 – Chris, are you using a toothed blade? If I recall correctly, you intended to go to a roughed surface for this bench. Question #2 – If so, do you use the pointed scraper plane style of blade, or the tiny chisel-style toothing of a regular toothed plane blade? Question #3 – 18 or 25 tpi? Very Curiously Yours – RD.

    • When you say the pointed scraper, do you mean the original style toothing plane ?because the ones made today by LN and Veritas are the odd ones.

      • rondennis303 says:

        The toothing blades that I associate with veneering look like “V’s”. All of the toothed plane blades look like a series of tiny chisels.

      • I think you might have missed the point of my comment. The V style for veneering are toothing planes. the new blades made today are just plane blades with slits in them. not exactly the same thing. I just always find it funny when the old original of something is deemed the odd duck, when in reality the new version is the odd one.

    • lostartpress says:

      Ron,

      I flatten it with a jointer plane. Then I tooth the surface with a vintage toothing plane. I’ve been using that surface for a couple years now (maybe more). My plane is an old German one, so I assume it has V-grooves. And I’ve never counted its teeth.

  4. Darn green wood doing that whole drying thing. Darn you.

  5. Brian Eve says:

    This is very interesting to see. I think that I might have slowed down some of the shrinkage on my bench top my keeping a wooden dowel in each dog hole, although some of them are a bit tighter now than they were when I first put them in there. I think when using thick lumber for a Roubo, one shouldn’t count on the wood behaving the same as 4/4 lumber no matter how long it has been out to dry.

  6. nickbrak says:

    Those midwest winters, cold and dry, when you warm up the air its even drier, Rel. Humidity. is probably in the teens; you had mentioned in an earlier post your holdfasts were rusting overnight, that was in the fall, Rel. humidity was much higher back then and you had hauled that wood/bench from the south. You could be in for quite a fun time with your top this winter. Sounds bad but this will be an interesting effect to watch. Thanks for letting us know the trials of a woodworker, its nice to know experts have problems as well. (As an novice I look at all the wonderful work in the magazines and get discouraged, and then the advertisements start to play on my weaken state)…

  7. The very few times I have been able to use my FORP bench this fall/winter, I have also noticed quite a bit of movement. Luckily, I haven’t had time to flatten it yet, so that time hasn’t been wasted. The top has really crowned, as expected, but I didn’t expect it to happen so quickly. Mine is in my basement, so I am hoping it won’t crack into pieces before spring.

    • lostartpress says:

      Justin,

      For what it’s worth, that is exactly why Roubo said to orient the top the way you did. The crown in a good thing (better than sagging). This is not a new phenomenon.

  8. Ah, man, what a great visual of bench shrinkage, Chris!

  9. Looks like you’ll be getting regular workouts until the wonderful old oak has decided it’s done messing with you. I had these concerns with the wood acclimating properly when people started signing up for the build. I’m glad I decided not to join in on the bench build. I live in one of the driest areas of the country. My bench would have most likely torn itself apart. Although, I would have really enjoyed the group effort. The video of the build was amazing.

    • lostartpress says:

      I am honestly joking about the bench falling to pieces. This isn’t the first slab bench I’ve built. The one I built with a cherry top was even wetter than this one. They settle down after a year or so.

      So I’d do it all again. In a heartbeat.

      • I have a curly maple tabletop that goes with an unfinished end table project. I made it when we lived in Charlotte, NC. After moving here, the top developed two cracks with the grain starting along each end grain end. They opened up to over 1/4″. The wood was 8-10% when I used it in Charlotte. It’s really dry here. Usually hovering around 15% relative humidity and dropping as low as 10-12%. I’ve seen big douglas fir beams shrink a full inch. Wood gets bigger when it leaves here. That’s for sure.

      • Raney Nelson says:

        My shop is climate controlled at 30-40% humidity, so my bench moved quite a bit quicker, but I’ve had the same experience ( though I didn’t have any glue seams split). I’m due for another flattening sometime in the next few months. So what? For my money, this is just the nature of the beast – and one that I think we deal with if we work with natural materials. For planes,I have to move heaven and earth to avoid problems of wood movement, but for a bench? Let the damn thing move. Then flatten it. If we’re lucky, ithey’ll look old, macGuyvered, and well used before someone turns ‘em into a fixture at some martini bar or Cracker Barrel…

        Besides, it’s better without the damn finish.

  10. seawolfe2013 says:

    Hi Chris, I was afraid you would have this kind of problem after your post regarding the amount of moisture the bench top had. You may want to slow down the moisture loss by coating all the end grain, including in the dog holes with something like Watco Oil, linseed oil or any oil/oil varnish you have around. This will force the moisture to be lost only through the surface instead of being wicked out the end. I encountered the same problem (including cracking), in not so dramatic manner and was able to resolve the issues by encapsulating the work in finish. This forced the wood to dry out evenly. Crack propagation stopped. My situation involved some 8 quarter work that was not finished/complete when the humidity dropped to 15% for a few weeks.

  11. If your original moisture content readings are correct, you’re in for a roller coaster ride. Expect that bench to lose about 3/8″ of thickness and around 1 inch of width by the time it’s all over. That’s not counting all the extra material you’ll remove to keep it flat. Also, as the top shrinks in width, the legs will be forced out of square by the non-shrinking stretchers.

    • lostartpress says:

      That did not happen with the last slab bench, which was wetter.

      I honestly think most of the commenters here are off the mark on what happens with slab benches. And how finish works. And…

      • I can’t speak to your other slab bench, but any benchtop has to follow standard wood shrinkage rates.

        It did happen to my roubo, which was not as wet as yours. Oak top made of four 4×6′s at an average moisture content of 20%. Built 1.5 years ago. So far it has shrunk ~1/4″ in thickness, 5/8″ in width, and it’s still going. http://lllars.appspot.com/the_workshop/roubo_workbench/index.php

        Which is not to say it’s not a great bench. Someday when it stabilizes I’ll figure out how to make the legs square to the top again.

  12. tsstahl says:

    Nothing good ever comes from dealing with the French.

    Consider yourself taunted some more. :)

  13. Should you ever find the need to build another bench make it from mulberry. By putting one leg in a bucket full of water it will wick enough moisture into the bench that the only problem will be trimming the branches.
    My bench log finally stopped sprouting leaves this year. It was cut down and set on piers to dry July 2011.

  14. rwyoung says:

    Display font set to small when I read Raney’s post :
    “If we’re lucky, ithey’ll look old, macGuyvered, and well used before someone turns ‘em into a fixture at some martini bar or Cracker Barrel…”

    For a moment I thought he knew of a “martini bar IN Cracker Barrel”. Almost makes me want to go. Salt water taffy martini anyone?

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