Replies

1. 
   WillGeorge | Feb 16, 2010 08:09pm | #1

   I will ask if you are using only hand tools or machine tools or both?

   ... Any suggestions on ensuring that the cut on one side of the tabletop will match the cut on the other side?

   I got lost on that one! Did you plane the table top while clamped down flat?

   I wonder about breadboard ends on anything that wide.. But what do I know? I have seen breadboards split. Not that much wood to hold the curve that a board that wide can do.

   If you cut the table top why not just make the slot in the breadboard a bit wider so it fits the flat tenons?

   I think James Krenov did not alternate the board grain and he seemed to get away with it!

   For a table that wide would not wood or metal cleats help to keep the table flat?

1. 
   actuary | Feb 17, 2010 02:29pm | #6

   I'm using machine tools.

   Cleats might be a possibility but I don't want the endgrain to show and breadboard ends really do look nice. Also, the table is in 2 pieces, each one 42" wide by 48" long, so if both pieces have a finished look I can actually keep them separate. (Each piece will have a pedestal base.)

   I think I should have done weight lifting training before starting this project: these pieces are damn heavy!

2. 
   DonStephan | Feb 16, 2010 08:17pm | #2

   Thnk it was Garrett Hack in a FWW article who suggested a great approach that works for me. If you don't have offcuts, mill a 12" x 4" piece of scrap to the same thickness as the tabletop, and cut into two 4" x 4" spacers. Finally, cut a couple pieces of 4" wide 3/4" plywood about a foot longer than the tabletop is wide.

   Lay one piece of ply on the workbench, and one spacer at each end. Lay the other piece of ply on top, forming an open box. Screw the four pieces together. Lay the open box down on the tablesaw, push one set of edges against the fence, and trim the other set of edges so they are coplanar. Or place one of the plywood faces against the jointer fence and trim one set of edges so they are coplanar.

   Think of the open box as a collar, and slide it onto the tabletop, with the coplanar edges closest to the end of the tabletop. With the coplanar edges square to the side of the tabletop and at the appropriate distance back from the end, clamp to the tabletop. The coplaner edges form guides for a router to trim the top of the tenon, then flip the clamped top and collar over and trim the bottom of the tenon without touching the collar's clamps.

   This explanation sounds like a mess of day old spaghetti, but it's the best I could do. The article had a picture which helped me understand the concept.

1. 
   actuary | Feb 17, 2010 02:06pm | #4

   I have to agree with your spaghetti comment. Can you possibly point me to the article? None of the articles about breadboard ends--including Hack's--mentions this technique.

3. 
   joinerswork | Feb 17, 2010 08:45am | #3

   If you've squared the top, and it is true enough that you could scribe  a line (presumably using a marking guage) around it, why not reference off the end of the top and push it across the tablesaw, or push a router ( or rabbet/ fillester plane) across the top with its fence against the end of the top?

   Ray

1. 
   actuary | Feb 17, 2010 02:27pm | #5

   I have to remove material 2"

   I have to remove material 2" from the end so I think I'll still have to scribe a line on one side  using the end as the reference for the marking gauge. But you're right, once I've set up the router's parallel fence using the end as a reference, I can flip the board and go right to the next pass, and then go right to the tabletop's other edge. Thanks for the idea.

   It would be so much easier to use a tablesaw but the pieces are just too big to properly control.

   These large pieces are really cumbersome in a small shop...

1. 
   SgianDubh | Feb 17, 2010 06:32pm | #9

   "It would be so much easier

   "It would be so much easier to use a tablesaw"

   Actually, that's seldom the case with large panels such as the table top you've described.

   You're likely to find the easiest, least stressful, and most accurate way to make a tenon on either end of the panel is with a router fitted with something like a 25 mm diameter cutter and side fence as others have already suggested.

   As long as you have the ends square to the two wide faces, and straight you should, all else being equal, end up with perfectly straight and accurate shoulder lines.

   I have a sliding table saw that could handle a panel that size with impunity and I could simply push the long edges against the cross-cut fence and scribe the shoulder lines. I wouldn't, even though it's a doddle, because it may be that the long edges are not quite at 90º to the ends. If that is the case then I could very easily end up with shoulder lines that don't match.

   No, for me, for that kind of job on large panels, out comes the router, the large diameter bit and the side fence. It's a piece of cake done that way and all you have to do is waste away the bits of the full width tenon you create that you don't need to suit the mortices cut into your clamped ends-- a clamped end is British terminolgy for what Americans call breadboard ends. Slainte.

4. 
   DaveW | Feb 17, 2010 04:54pm | #7

   I just did this same thing on a dining table. My table field was 1 1/16 thick and the breadboard were 2" thick. Plus my breadboard were radiused rather than straight. You have to register off the top of the table to get the planes to work out.

   I opted for a 1/2" floating tenon and used a plunge router to make the mortises. It required a jig to hold the router in the 90° orientation, but it worked fine. Once the mortises were completed, I dry fit everything, marked for the dowels on the underside of the table, and then elongated the tenons to allow for movement.

   I glued the tenons in the breadboard and let them float in the table field.

   I can send a photo of the router jig, if you go that way.

1. 
   actuary | Feb 17, 2010 05:15pm | #8

   If it's not too much trouble, I would like to see the router jig photo. I'm working with somewhat thinner stock (7/8" for the top and breadboards) so a 1/2" floating tenon probably wouldn't work but I'm trying to consider many approaches before I dive in.

5. 
   actuary | Jun 15, 2010 10:30pm | #10

   it worked!

   I used the router's parallel fence on the straight edge and successfully created the tenon and stub tenon. With a little fussing, everything fit nicely into the mortises. The project is now totally finished and here's a photo of this dining room table for 12. The wood is quilted makore and the top coat is polyurethane. I used Abralon pads for the rubout.

   Thanks for all the suggestions.

   
1. 
   RalphBarker | Jun 18, 2010 11:16am | #11

   the finished table

   The finished table looks very nice, particularly with the curve in the BB ends.