My Ulmia workbench is about three years old. The top is slightly concave now due to changes in humidity. The concavity has changed slightly with the seasons but the top has remained concave. How do I go about getting it dead flat again without ruining it? This was an engagement present from my wife (she bribed me!).
Also, I gave the entire bench a coat of Watco when new. I was thinking a good dousing periodically might slow down moisture changes and keep the top more stable.
Also, what is the best relative humidity for the shop?
Replies
Mike
Hand planing is the only way I have ever trued them. But, I saw something clever in The Work-Bench Book that I am going to build. I think it was Frid that built a simple little jig that straddled over the top. The base runners are the same width as his router base. Attach a straight bit an slide the router across at a pre-set depth. Move the jig over an make sucessive passes till the whole top is trued with the aid of that clever idea.
You can apply Watco penetrating oil as often as the top drys out. I also wax with Butchers wax (used on bowling alleys) after the oil drys. No penetrating oil will seal completely an keep the moisture out. If you can keep around the same humidity inside the shop year round, regardless of degree; that will go a long way. I do no know what the perfect humidity is for minimum movement. I rely on instinct an a moisture meter to tell me what needs to be done to keep things stabalized. If it's wood, it's gonna move. That's a fact.
Again, good luck...
sarge..jt
In theory, it's relatively easy to flatten a large top with handplanes. In practice, I would not want this to be my debut with handplanes, straightedges, winding sticks, and the rest. True, the top is thick and you've got elbow room to eventually get it down to flat. I'd try using handplanes to prepare and dress the broad surfaces of my next project and see how that goes. It will be a bit of a learning experience. Once you've got a comfort level, then flatten the top. Once you've removed what appears to be the 'permanent concavity' you do realize it will continue to move and need reflattening from time to time. However, my experience is that the sessions down the road are strictly nip-and-tuck procedures and not full-body makeovers like the first flattening session usually is. But others will have had different experiences. Every workbench is different and every slab top is different. Pay little attention to broad generalizations, and don't subordinate your own judgment to others. Let thine own eyes reveal what's happening in thine own shop.
As far as the Watco goes - yes, yes, yes, and three times a year on all surfaces - top bottom, edges, and ends of all parts of the bench. You can do the Watco watussie whenever the mood strikes you. It can't be overdone. Just follow the instructions on the can. Lay the rags out flat on the driveway to dry. If you don't, you'll burn your shop to the ground.
If
I've actually trued a few boards by hand but nothing as large as a workbench top. I took the fundamentals class at North Bennett St a few years back. The class focused on tuning up hand tools, squaring up stock and hand cut joinery. I'm not certain it prepared me for the bench top though. Just a little bit scary. I have Frid's books and the Workbench book. I'll check them out. I do need to make winding sticks. I've read about them, have used them once when building a kayak kit, but that's it. I'll do a little more research and then dive in and hope for the best
Have a look at this old thread of mine. It maybe of some help.
http://forums.taunton.com/tp-knots/messages?msg=12745.1Scott C. Frankland
"This all could have been prevented if their parents had just used birth control"
In the interest of fair disclosure I'm not as fastidious as I used to be about making a pass here and there to keep mine flat along it's entire width and length. Sgian is continually pleased to know this.
Look, your benchtop, once flattened really well will usually maintain pretty good flatness over a relevant area. Now, if you're truing the leg lengths on a big Southern Huntboard that's seven feet long and you intend for the top to provide the reference surface, I suggest that the bench have as little twist (cup, ect) along it's entire length as you can manage. Of course, winding sticks are your saviour here, but only if you understand how to use them. A six foot long extruded aluminum level also provides a refrence straight surface that will help identify the maladies which concern us.
All my comments pertain to a commercially made workbench top of strips of Beech, Maple, or some other suitable material which should be what you have since you've purchased one of the best.
I think Ulmia is out of business, so take good care of your bench.
To be honest, the router and sled method scares me worse than the patient use of handplanes. Building a sled and all that - not for me. I've no doubt it would work, but I can imagine a lot of things that could go wrong. The only bad thing that could go wrong using the traditional method is misreading the winding sticks, which is not impossible to do (it's easy to take a corner down too much and reverse the direction of twist). You have to constantly check all directions with your long, refererence straight edge - across the slab, down the slab, diagonally across/down the slab, then the winding sticks again. But the work can be done to your favorite music and without all the protective devices on.
Edited 8/27/2003 7:00:43 AM ET by CHASSTANFORD
Edited 8/27/2003 7:02:47 AM ET by CHASSTANFORD
I checked the flatness of the bench the morning (across the width) with a 24" Starrett straight edge. It's out less than 1/16th at the center of the cup. I'm going to oil the bench up and see what happens this fall as the air dries up. The I will decide if I will flatten it.
Nah, Charles. That classic thread is no more than a ghost. It disappeared along with the WebX format that Taunton used to subscribe to.
ALL. Some background for newer contributors. I started a thread two or three years ago called something like, "Flattening workbenches, and other hoary old chestnuts." Charles and I were the main protagonists, and we went at it for over a hundred posts.
After several years of neglect, I'd just spent time flattening my Ulmia bench top with hand planes, winding sticks, slapped a bit of finish on it, blah, blah. Prior to flattening it was quite out of true, but I'd been making furniture on it in this state for several years. It changes as the seasons change. Anyway, it prompted me to ask the question of myself, "What's the point?" It became the thread title above.
My bench is not perfectly flat now. It's better than it was before I flattened it, but its flatness alters as the seasons go by. We have just two significant seasons here in Houston-- summer from November to March, which is pleasant, and somewhere south of Hades every other month of the year, which is hot, humid, and rather unpleasant.
There is no form of climate control in my metal building workshop, which is typical for the area. During the south of Hades season, it's not especially unusual to see temps like 95- 100°F+ in the workshop at some point during the day and humidity readings of 50- 60- 70% I've seen 125°F in my workshop more often than I care to recall-- I didn't last long on those extra toasty days before I left for a more suitable venue, probably an over air conditioned, chilly, well insulated bar with an ample source of the brown frothing stuff, ha, ha.
Currently I'm closing down my business, and packing up my gear. I've dismantled my workbench, and all my stuff is being shoved into a container and will reappear in some weeks back at home in merrie olde England where I'm moving to. That bench top is going to experience different seasonal changes to the ones its been through for the last eight or so years. No doubt it's going to move a bit, and I imagine it will seldom be perfectly flat, but I expect I'll be able to continue to knock out a few of my rough old sticks as the mood takes me.
In other words, I agree with Charles. There's no need to get too knicker twisted or anal about a perfectly flat bench top. It's handy if it is today, but in a month or two, it probably won't be flat. There are always tricks that allow you to work around less than perfect bench flatness to achieve square cabinets and frames, etc, such as shims, winding sticks, and dead measuring diagonals with rules, tapes, and folding sticks. Slainte. Website
Sgain
I have a feeling that your top will change radically when you ship it Conex container over to England. That long boat trip will give it time for all the American Beer you've spilt on it to evaporate. I wonder if the English beer will effect it differently? Much denser content an could cause some real surprises.
If it warps that badly, you could just throw a machined metal top over it an add some Watco. The Watco on metal will make it slicker than a "babies bu*t" an excellent for grease wrestling if you add ropes around the perimeter. ha..ha..
Hope all is going well with the move...
sarge..jt
We'll see what English beer does to it, Sarge. Oh, and maybe the climate too? Slainte.Website
Sgain
Regardless of how the beer an climate affects things, I am totally convinced you will adjust too the changes with minimum effort. "The cream always rises too the top".
sarge..jt
My wife and I want to buy property in the most obscure, desolate part of the Scottish Highlands and tell the world to kiss our a*ss (es). I'd like to do a little woodworking and raise sheep the rest of the time.
I wish you the best of luck on your move. I have a gut feeling this is the right thing for you, for what that's worth.
Take care,
Charles
Edited 8/27/2003 9:25:33 PM ET by CHASSTANFORD
Charles, that'll be some place like Toscaig, the end of the road on the Applecross peninsula, and a few miles south of the relative metropolis of Applecross itself with its village shop and bar, ha, ha. Overlooking Skye, remote, and wildly beautiful. Across the other side of Loch Carron by boat, you'll find Plockton, famous for its mild climate able to sustain palm trees along the sea front. The sheep will largely look after themselves. Your problem will be finding and rounding them up, ha, ha.
I'm not moving to somewhere that remote. My destination in the UK is about 15 miles east of Oxford. Not remote at all, but pretty in a rollingly Agatha Christie way, and expensive to boot, ha, ha.
Thanks for the good wishes. Slainte.Website
I'm taking notes. Your spot sounds nice, too.
I've lived in Sugar Land for the past too many years. I read with great enjoyment your description of the SE Texas climate. It has been all I could do these last few weeks to force myself into the shop, which has no climate control. Unfortunately the projects are mounting up and I sit in my easy chair directly under the central air vent. The salt from my sweat stained some raw wood I worked on.
I traveled back and forth to London staying a month at a time a few years back, working in the energy industry. It was the most wonderful experience. I actually got a lump in my throat when my assignment ended and I knew my fate was eternal damnation a couple of miles off US 59. I've seriously considered selling my possessions and living in the English countryside, doing some kind of work, who cares, anything.
I'm sure you will be saying kiss my arse goodbye as you leave the tarmac at Bush, I know I would. Take care.
Darn, Charles, if it wasn't lost forever in cyberspace we could point him in the direction of the, "Flattening workbenches, and other hoary old chestnuts," thread. Ha, ha-- ha, ha, ha, ha. I think I need a drink. Slainte.Website
It was a classic. I wonder if it's still available in the archives.
Charles
I got real interested in hand-planes a month or so ago an find myself using them more. I never thought I would say this, but I am really starting to really enjoy using them.
There, I said it.. ha..ha..
sarge..jt
I'm glad to hear it. Life's too short to not make pleasing new discoveries.
Good luck with your woodworking.
Charles
Odd that you mention moving to Scotland. I am nearing total retirement in the next few years (partly retired now). The congestion, traffic and what-ever has become horrendous here in Atlanta. Especially when I grew up when that was not the case.
Our main points of interest have been narrowed to an area in the Appalachian Mountians in the Tenn., N.C. an Va. corner where they meet an Scotland. I was fortunate enough to visit there years ago in my world traveling days an loved everything about it.
Good luck with your plans...
sarge..jt
Those sound like decent plans too. Best of luck in your retirement.
I recently glued up a maple bench top and flattened it with the Frid method. I used 1 x 2 fir strips handplaned straight by screwing them to the sides of the slab. I made a carriage that spanned the rails and allowed two passes with each setting. Some observations:
1. I wasn't optimal in setting up the rails and ultimately lost about 3/8 inch total thickness from the two sides.
2. I cut 1/16 too shallow the first run down the top and had to do all 80 cuts and 40 re-settings to clean up the entire top.
3. The top was VERY flat and without any twist. I cleaned up with a #80 handled scraper and it came out very good!
Some advice, if you use this method:
Think for a long time about mounting the rails and setting the cut depth. You only want to go up each side - not up and down!
Make the sled really stiff. Tighten the router bit really well. Keep measuring the distance from the rails to the flattened top. Fill the screw holes from mounting the rails with dowels when you're done.
I can't speak to handplaning the top. I built a good bench to learn to use hand tools well, but I don't yet. If you'd like a picture of my sled, post and I'll put up a couple.
My first thought when I read that you'd put Watco on the bench was that you did the top and not the underneath ... thereby creating a situation where the bottom was more receptive to humidity changes than the top. Chasstanford mentioned that you should put Watco on all sides, and I'd second that recommendation.
John
When you put on the WATCO on the top side did you do the bottom also?
Who ever invented work didn't know how to fish....
I did put the Watco on the entire bench. But that was several years ago. I may have put another caot on the top since then but I can't recall.
I did a maple bench top about a year ago now using the router/sled method for next-to-final flattening, and with Charles--it is a long, noisy, dusty process. The sled itself needs to be stiff with a certain amount of vibration dampening. I used 1/4" x 2" x 2" aluminum angles with strips of maple screwed into the sides (there are better materials for this, but I had them on hand). The top was 32" wide and the angles were 36", so there was not a lot of room at the ends. I straightened and flattened two pieces of 8/4 fir and screwed them to the bench itself proud by ~1" (final position trued with winding sticks).
The process is tedious, but it can get you there. I found that the sled I used was not quite rigid enough, and left a slight hollow in the middle. By mid-winter, it was pronounced enough to annoy me, so I re-flattened with handplanes--a pleasant 45 minute task. Doing it that way the first time would have been a pleasant, two/three-hour task, instead of an all-afternoon power-tool ordeal of setup, jig making, and mud-wrestling a twelve pound screaming yellow monster. Live & learn....
/jvs
If you use a hand plane, use the longest one you can get, adjust for paperthin shavings and cut at a 45*diagonal across the grain. Some decades ago the family bought a 14" thick 50y.o. butcher block 24"x36" that was about 2 or 3" out of flat in spots. Us kids were assigned the flattening duty. One kid drove the truck towing the block upside down on a concrete road while 2 kids rode the block at about 20mph. The result was acceptable (after a belt sander touch-up) but not within 1/16".
I prefer the answers above that accept the natural curve slight modulation. But then I've long held to a variable standard of approximately perfect.
Years ago I made a series of work benches, tables and radial arm saw extensions using a frame work of 2 x 2 angle iron,for rails, legs, braces welded and bolted together. The top has cross supports ever 12 or 15 inches on center like joist in a house. To that I've simply bolted 3/4" plywood. Is it flat? It should be. If it's warped I just shim the legs up. The only problem I've had is getting a clamp to work with the angle iron frame....details.
Every once in a while I think I should replace the top, but then I just scrape of the glue and junk stuck to the surface and keep going.
You do know this thread is over 5 years old...
I just did a new bench top a couple months ago following the flattening method on this link. Worked great
http://www.highlandwoodworking.com/index.asp?PageAction=Custom&ID=58
If you build it he will come.
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