[OP]
Member
Well I spent hours getting my roubo workbench top perfectly flat across and along its length. But that I use as a reference surface in my shop. Is there a reason the top of my dining table needs to be perfectly flat or is it mostly flat I’m going for?
Flat on the aprons I would have thought would be mostly for stability...
Moderator
Flat is relative for a table like this, Dave. As long as it "looks" flat and is well supported, something of that stature doesn't need to be ready to be a machine shop reference surface.Leveled so it looks like a continuous surface is more important and that's one reason I suggested the wide belt treatment once you have it glued up...getting the whole schmegeggi the same thickness so it looks like it's a continuous surface like I just mentioned.
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The most expensive tool is the one you buy "cheaply" and often...
Member
I want a 10 foot dining table something like you are building so I find your experience very interesting. I am concerned with the weight of the top. I have an old Woodsmith magazine where they faked a thick top with plywood and made the breadboard ends removable so a narrow leaf could be added at each end. A 10 foot would fit in my 16 foot dining room fine, however. I might look for a sheet of nice 9 foot long plywood and still have solid wood breadboard ends - just skip the leafs. The plywood will not be as durable, however. My plans are cherry top and an ebonized softwood base (I had great luck with black ink on softwood making the mobile base for my sawstop).
Anyway, enough of my project. Yours is looking great. I would use dowels or loose tenons or possibly splines to get the boards line up as well as possible during glueup. I would cover the floor and do the glueup in the dining room. A hand plane would limit dust but I would probably use my Bosch 1250DEVS sander hooked up to a shop vac with HEPA filter. Turning if over to do the bottom will turn into a major exercise if I do solid wood. But turning it over is lifting half the weight. Carrying it would be much worse.
In my case, I am not worrying about moving the table. I don't plan any more moves and my kids can figure something out when I'm gone. A 10 foot long dining table is never going to be an easy thing to find a new home for.
Member
For what you paid for the walnut paying a little extra for a wide belt sander is worth it.
I built a similar sized table out of reclaimed freight train flooring. It was 2.5 inch maple. I built the top and legs in the garage then had a buddy help me carry both separate pieces into dining room. It was not a problem. The table top is heavy but once it is upright it was easy to maneuver. My wife helped a bit when it was time to get the top horizontal.
you ought to post pictures of this when done — a walnut table that size is going to be beautiful.
Moderator
Your dining table will be easier than your workbench to flatten. I agree with Jim. Local flatness is more important than global flatness here. However, his statement of 'leveled so it looks like a continuous surface' is rich. I would still use a straight edge to look for dips and undulations from any aggressive sanding you might do. These will certainly become apparent under a glossy finish...
...so the other tip is don't use a glossy finish. A satin finish is more forgiving on many levels here.
Moderator
Prashun, the wide belt should actually deal with the dips and undulations you mention...I know it did for my recent kitchen table project and it only took two passes!
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The most expensive tool is the one you buy "cheaply" and often...
Member
Dave, yeah removing or lowering the rabbet ledge on the jointer is a must!!
Of course with the guard removed, be very careful, or better yet, make a homemade euro type guard you can clamp to the fence.
I think you'll find everything will works now.
Finding a shop with a wide belt is the best way to go but may not be that easy. I live near a major metropolitan area and gave up after calling 3 different shops that were recommended to me. I'm sure if I kept looking I could have found one but my glue up was close enough and the top flat enough I was able to do it with the tools I had.
If there is a local woodworking club or Woodcraft store nearby you might check with them.
For a top that big and thick, you might also consider a router planing sled. A bit time consuming, but you'll get a good result.
BTW, evenness is probably more important than dead flatness for a dining table. I wouldn't fret it too much.
Last edited by Robert Engel; 02-19-2019 at 10:22 AM.
I just want to share my 'learning opportunity' on a recent table top I built with similar dimensions:
Once I get pieces milled in the future, I will move as quickly as possible thru the table top build. My table top sounds similar to yours. All I built before this was smaller tops and I didn't really think of the time issue. With big tops, a small change in moisture content can have a big impact on the shape of the top. Mine developed a substantial cup (which at first I thought was against the growth, but realized it was with the direction of growth). Once I had a huge cup, I could not really send it to the big sander. I wasn't able to take off more than 1/8" to 3/16" before my design was impacted. I bought a really nice belt sander (Makita) and spent countless hours running it over the top to make the top 'flat' along the curve. The point is, if I had done everything quickly and applied oil as soon as I could, the table top may not have moved noticeably or at all. Or worst case, if it did move, it would still be 'flat' across the curve because I would have taken it thru a belt sander first.
I'm not sure if other more competent woodworkers would agree, but unless I see otherwise, I will now plan to get the top done as quickly as possibly and put at least one coat of oil on as soon as possible. This was a painful experience that I do not wish to repeat.
I also wonder: do you guys build the top first or last? I think top first because the height of the table, apron widths (or whatever you are using for spacing) will need table top dimensions. I built my top first, but set it aside before oil and then built the legs. I think this was my mistake. Do you guys put some sort of easy to sand of oil if you know your top is going to be sitting for a while?
Cheers,
Contributor
I saw a floor finishing sander once that was very controlled (dont think it was the usual drum sander type, more of a vertical orientation, it didnt take off a lot and left a nice finish).
But I wonder, if you put that glueup on the floor and rented floor sanding equipment...
Contributor
If I were looking to do this I would find a local CNC shop to toss all my boards on the deck. Squeeze them together on the end lightly with some clamps. Deck them off with a fly cutter. Flip, Re-clamp lightly, deck off the second side. You take them back to your shop and rip on your table saw as needed. Glue up the top worrying only about the edges not the faces. Then bring it back to the CNC shop, toss it back on the machine with the worst face up. Deck it off flat enough for a table bottom. Flip it. And deck the top off at a feed rate that will leave you with a 150 grit finish to take back to your shop.
Contributor
This is likely due to your choice of flat-sawn wood, rather than quarter-sawn.Originally Posted by andrew whicker
"Anything seems possible when you don't know what you're doing."
Member
Dave, I've been through this before but also have the good fortune to have the equipment suited for working with large slabs.
Here is an idea that I have not seen mentioned.
Forget flattening first. Instead edge joint the planks - using your jointer if practical and a track saw if not. Another option is a track guided router with a 3" spiral upcut 1/2" diameter end mill in it.
Next, glue up the top.
Then, after the glue has dried use a router sled to flatten the entire top. Sand after flattening and you're in business.
Granted, if you can take them to a local shop that has a large jointer / planer, then by all means do so. If not you can do it at home with the method outlined above.
In this pic I'm using a Festool track, Router and 4" long end mill to edge joint a 4" x 10" quartersawn oak plank for a bench top. Tolerances were dead on on the glue up.
IMG_3177.jpg
Contributor
With regards to this thread, who in their right mind would pay for quarter sawn walnut? Flat sawn FAS is like buying bars of gold. Makes zero sense.
Member
Ha! I finished building a table in walnut that's just over 9' long and 44" wide late last fall, though I used 5/4 for the top. The top was a big enough glueup that I did it one joint at a time; I also used dowels to help with alignment, but it turned out to be quite difficult to get as many dowels all lined up at once as I wanted, so I ended up just putting 3 dowels in so that I could get the joint closed up before the glue set (that's almost certainly due to small errors on my part adding up over the 9 feet). Carrying the top from the basement up to the dining room was almost a full-blown project in its own right, I can't imagine how heavy a 2" top is going to be! I did glue the apron/leg assembly together in the dining room, as I wasn't going to be able to get the glued-together base up the basement stairs; the top is fastened to that with z-clips so that we can take it apart if it ever needs to move; the base should be small enough to get through the front door.
I haven't put any finish on it yet as I'm waiting for spring when I can ventilate better first (but the table was assembled on Thanksgiving day two hours before dinner!) I was planning on a glossy finish but after reading through this thread I may have just changed my mind in favor of a more matte finish, as I'm certain that my less-than-perfect flattening and sanding job will surely show; we're just using a waterproof tablecloth in the meantime. I used a 4" belt sander followed by a ROS followed by 3 days of sweeping and vacuuming the basement for getting the glued-up pieces leveled. The one place I ran into some trouble was rounding the corners; I rounded the corners of the tabletop followed by a roundover; I did one final touchup pass on one corner only to realize that I had carelessly let the router bit drop and it left an extra unwanted groove IMG_20181122_100422131.jpg so I ended up having to shorten the entire table by 3" to get rid of that - but after I did, I had a ton of trouble getting my corner radius jig to register properly on the already-rounded-over edges (eventually solved by me realizing that I could use my longer flush-trim router bit if I put the radius jig on the bottom of the tabletop, but it still took a bunch of sanding to cover up my mistake there). I can't wait to see what this is going to look like with finish on it....
IMG_20181122_143808351.jpg
Member
Where I buy my lumber, quarter-sawn is ~ $9.75/bf vs. ~ $6.00/bf for plain-sawn - so, about a 60% premium. I guess it depends on the application, the size of the project and the size of your budget. For the OP's project, personally, I'd stick with plain-sawn (my wife gets cranky when she doesn't eat for three weeks).
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