First table since high school (25 years ago).
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Here is my table completely within specs. Almost. I used mostly 3/4 inch stock for all but the legs. It all came together great. But the other day I noticed the top was cupping!
The finish is some sort of danish oil, so what I might do is let it be for a few months and see if it comes back, gets worse or stays the same. Then if needed I can take the top off, re plane it and put more oil on it. Should do the trick if nessesary.
Now I’m working on a matching coffee table with much thicker stock.
Jeff
Dear Jeff,
Looks nice.
Hope you don’t mind a thought on cupping too much. If it is caused by seasonal changes in humidity or by tension in the wood, then a batten running as a non-tapered sliding dovetail along a socket at the bottom of the top can be an alternative.
An 8 mm (5/16″) deep x 18 mm wide dovetail, bevelled at 1:4, resulting in 2 mm wide shoulders worked on the piece seen in the picture.
[attachment file=”808120″]
Sorry, but I forgot to mention that the top needs to be ripped along the edge. Then, when the batten is in place, the ripped off piece is glued back again, hiding the opening of the socket.
There is a video on making a table with a drawer running through the front apron demonstrating the technique.
Sometimes, people put their turnbuttons in the wrong place to resist the cup. Is that what is happening here? If you think about where your turnbuttons are and where the cup is, would they resist the cup or are they in the wrong place? On this table, they would go on the left and right rails, not the front and back. Two of them, dividing the distance between the front and rear rails in thirds ought to do the trick.
After thinking some more, 2 in the center of the side rails and 2 in the center of the front / rear rails might also work. The ones in the center of the side rails would resist the center rising upwards (downward cup) and the ones on the front / rear rails ought to keep the sides from rising upwards (upward cup). It wouldn’t be crazy to put two on the front and two on the rear (near the corner) and one each in the middle of the two side rails. In any case, think in terms of cupping in both directions and whether your turn button placements will resist both.
Thanks for the quick reply’s. I’ve used batons before on bare chest lids. Although not being fancy dovetailed in, they did work.
I just measured the cup. At the worst end it measured 7/8th of a millimeter. At the opposite end it wasn’t measurable.
Talking about turn bottoms, I’ll try tightening them first since that’s the easiest. If that doesn’t work then I’ll try one of your guys’ ideas.
After looking more closely. I checked with a 12” straight edge and found that both the two boards that make the top are dead flat. It’s only at the joint where it comes in. Making me believe that one side of the table tops edge was not joined perfectly.
So now I think the best two options would be to either re plane the table to dead flat or live with it. It does take eyeing and feeling it a bit to tell. I think I’ll live with it for awhile and see about planing it this fall.
hi Jeff,
it’ a fine looking table , sign and date it and move on to the next project (unless it really, really bugs you!) if you don’t point it out, 99.9 % of people won’t notice, and if they do…..so what!
come back to it in a year or so and decide what (if anything) your next move is.regards
Barry
I wouldn’t blink at such a small amount. Your turn buttons look good in terms of placement. The apron of that table is so strong compared to any cupping forces that, as long as the turn buttons are tight and as long as they are actually pulling down on the table top, it shouldn’t be possible to cup.
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