Replies

1. 
   RSRose | Oct 14, 2002 04:09am | #1

   Dario,

   Here's another way:

   Tack straight rails to both long edges. The edges of the rails need to protrude an inch or so above the surface of the table. The proud edges of the rails describe the plane that the top of the table will be milled to. Build a sled that carries a router. The sled rides on the rails and allows the router to move back and forth between the the two long edges.

   This jig is described in many router books and in "Tage Frid Teaches Woodworking." It's a good way to mill a surface that's too big for stationary equipment. Use a straight 1/2" bit. It's slow, but it works very well.

   Rich

1. 
   arail2 | Oct 15, 2002 04:52am | #7

   1. Use a jointer to flatten all your boards before planing them.

   2. Plane all the  boards to a common thickness.

   3. Use a jointer to make sure all of your board edges are straight before gluing up.

   4. Use a biscuit joiner with biscuits spaced approx 8" to 10" apart to keep your boards flush on the surface.

   5. When you clamp up, alternate one bar clamp under the surface and one above to even out any distortion caused by clamp pressure. Use a steel straight edge to check the surface. If you have any curving, increase or decrease the clamp pressure at that point to eliminate it.

   6. Use a random orbital sander for minor cleanup followed by hand sanding with a block along the grain line.

2. 
   UncleDunc | Oct 14, 2002 04:44am | #2

   Another alternative, since drum sanders are expensive, is to find a shop that has one and pay them to flatten your panels.

3. 
   JeffKurtz | Oct 14, 2002 06:08am | #3

   Dario,

   Are you careful that all the stock you're joining is flat and of equal thickness and that the sides of your boards are jointed square to the surface?  If that's the case, and you're clamping on a good flat surface using cauls or their equivalent, you should end up with a top or panel that that requires very little surfacing.

   Jeff

4. 
   DennisS | Oct 14, 2002 07:03am | #4

   Dario -

   I watched some boat builder types flatten some large glued-up landing pieces for a stair. They used a "long board" system. This consisted of a piece of MDF, ripped as wide as the kind of adhesive sandpaper you can buy in roll form. Joint a *perfectly* straight edge on another piece of MDF to form a rim or two along the top of the first piece to keep it straight and flat. Glue/fasten the rib(s) to the first piece and attach the sand paper to the entire length; the length being at least as wide as your table top and perhaps longer, maybe as long as the length instead.

   Long work pieces really require two people, one on each end like the old two-person crosscut saws. Weight the entire length of the long board with evenly distributed sacks of something so there's equal pressure along the entire board. Work in many directions to ensure a flat surface. Yes, you'll have sanding marks to remove if you go too far out of parallel with the grain but you'll have a flat surface.

   Poor man's (person's) widebelt sander?? (grin)

   Dennis in Bellevue WA

   [email protected]

5. 
   RW | Oct 14, 2002 08:27am | #5

   jumping on the established bandwagon . .

   pay attention when you're glueing things up to get it as flat as feasable, belt sanders can work ok, esp if lower speeds are used. I'd learned an X motion (diagonals one way, diagonals another until flat) that seems to work, but the best so far is the cabinet shop. When I was stationed in Montgomery, AL, Marshall Millwork & Lumber was right outside the gate and any panel I'd bring them they'd run through their wide belt sander for five bucks. What a bargain. That was my kind of southern hospitality! Now I barter with a cabinet shop. Every so often, one of us decides the other is in debt, and work occurs. I've gotten a lot of things flattened or just ripped straight (there ain't much a $25K table saw can't do to great big rough lumber) and he's gotten spraying tips and new sides on his trailer.

6. 
   ChasStanford | Oct 14, 2002 02:10pm | #6

   I'd urge you to give your handplanes another try.  You need  a pair of long winding sticks and a 6' carpenters level to help you identify the high spots, twist, cup, etc.  Handplanes can remove a frightful amount of wood in a hurry - a scrub plane sure as heck can.  The point being is that once you've 'quanitified' the out-of-flat condition, your handplanes can correct it faster than you may believe.

   A quality drum sander would be the most realistic machine alternative for flattening the panel.  Planers do not flatten wood, they only make it thinner. 

7. 
   BernieMaas | Oct 15, 2002 06:24am | #8

   After years of belt sanding until I'm blue in the face, I gave up and took a couple of tabletops to a  cabinet shop with a 36" sanding mill.  For $15 a piece I had the tops sanded dead flat down to 80 grit.  I would have spent that much in  3 x 24 sanding belts and random orbit paper plus the dust and cleanup.  dustless sanders - belt or random orbit - does not mean "no dust" - just, not as much dust.

   There are several shops with these large sanding mills in my area.  In fact, one even offered to do the work without charge since I do bring in a lot of lumber purchases.

   Bernie Maas

8. 
   gweisenburge | Oct 15, 2002 07:15am | #9

   My experience with wide belt sanders (my next door neighbor has a 42-inch Timesaver and I've owned smaller ones) is that they dimension sand, and they don't flatten wide glue up panels. Like a planer, wide belt and drum sanders press the glued up panel flat against the feed belt. If the panel is cupped or twisted, the sander will press the piece flat, dimension sand the piece to the thickness set, and then when it comes out the outfeed end, the cup or twist will still be there. You've got to "joint" the piece flat before sending it through a dimension planer or sander.

   Tage Frid's router method works, but I like to use winding sticks and scrub planes, and finally jack planes to do the jointing or flattening work. If you're in a hurry, you might use either of these methods to flatten one face (the underside), and then take it to your budy's Timesaver to dimension sand the other face.

   My favorite flattening system is hand planing, especially on the wide, solid walnut and butternut slabs I've worked. I sometimes begin by cheating the wood off with my electric Makita hand plane, but I'm eager to finish with that and begin scrubbing and finally scraping before random orbit sanding. The process is really a joy, especially since I can listen to music after turning off the electric tools. If you mist the wood (just dampen it), scrubbing difficult grain with a sharp iron will be easier.

   Gary

1. 
   riverr1 | Oct 15, 2002 07:30am | #10

   Everybodys neighbor should have a timesaver!

   What's the router method?

   Thanks, Don

1. 
   RSRose | Oct 15, 2002 11:02am | #11

   Don,

   I described the router method in the second post in this thread.

   It works very well. It applies no pressure to the boards, so it doesn't flatten any curvature before stating to mill off the high point of the curvature.

   Rich

2. 
   dcarrara | Oct 16, 2002 04:50am | #12

   Thank you Gary, and everyone else too.

   Lately I have been using rough lumber to start. This has led me to understand that I must flatten the board first, before any other operation. I am in the process of buying an 8" jointer to do just that (see other discussion). I want 8" because I want the bigger motor and longer tables, but more than 8" is just too darn expensive, and heavy! I've noticed that boards do not get flattened in the planer, but I want to build the planer sled (can't remember the FWW issue #) to flatten boards > 8" in width.

   Thank you all.

   Dario

1. 
   AlanTurner | Oct 16, 2002 02:59pm | #13

   Dario,

   I built mine from two lengths of alum. "H" beam, about 2" tall, and 1.5" wide on the flanges, and carefully drilled and bolted (screwed?) MDF to it. Then put shorter lengths between the two long beams to reduce or eliminate deflection. Still have it, and no longer need it. Anyone in Southeastern Pa can have it, as far as I am concerned. I now have wider tools. But when a board iswider than my jointer, but narrow enough for the planer, then I just use a piece of MDF, 3/4", and it sems to work fine. Hardwood wedges are the real trick since the force fo the planer cannot squash them.

1. 
   dcarrara | Oct 20, 2002 04:47am | #14

   I have found two relevant FWW articles:

   #132 "Making Tabletops Without Coming Unglued"

   #141 "Gluing and Clamping Strategies"

   These really helped me out. Soon I will try my hand at flattening the tabletop.

   Dario

9. 
   rslatm | Oct 20, 2002 09:01pm | #15

   The key is to prepare your stock first by acclimating it to your shop. Lightly joint and plane the stock flat, leave oversize and sticker it in the corner of your shop for a few weeks. Some of it will move a lot and hopefully the rest will remain relatively flat. Mill a few extra pieces to allow for this. Now finish mill it to size. For best results glue it the same day you joint the edges. It's a myth you need a giant planer. Actually all you need is a planer as big as your jointer. I would get the longest 8" jointer you can afford. The other key thing is to make sure your wood is all the same moisture content. One wild board will cause lots of problems.

   Rather than spending on a big planer, get a moisture meter. The glue up is easy if you use the curved caul method. I've glued up perfectly aligned 4' x 8' panels single handed. Photo is of the curved caul method with veneers. For panels eliminate (A) the plywood. Place the cauls on two beams running prepindicular to the cauls. It's actually a poor mans Plano glue press. Put plastic tape or saran wrap on the cauls so the glue doesn't stick to the cauls. A set of cauls every 12" to 18" will suffice.

   Rick