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+-- Thread: twist advice needed (/showthread.php?tid=7236383)
twist advice needed - pinky - 03-05-2016
I need some advice. I started a slab table. I picked up some cast iron legs off an old metal lathe. Going to mount a 1/4" thick 9" x 20" steel plate to each set of legs. The top is 32" wide. 2 pieces of 16" wide bookmatched curly black walnut. Now on to the problem. One of the boards had a twist in it. These 2 boards started at 5/4. I was able to get access to a 20" jointer and 24" planer. Face jointed one side and then planed the other and was pretty happy other than I was down to 7/8" thick but decided it would be good enough. Glued them up and they were looking good. Now the twist is returning to a certain degree. I do not want to do breadboard ends. Here is my thought and was wondering what the brain trust thinks. I was thinking of cutting multiple kerfs on the tablesaw the length of the top on the underside...76" to release the stress. I'm not really concerned with how it looks underneath. I will fill the ends so you don't see the kerfs from the end of the table. Does anyone think this will work? How deep of kerf would be needed in 7/8" material to possibly work without making the top too weak? Any advice or comment will be much appreciated. The learning lesson so far is to walk away from a twisted board no matter how pretty. But would like to make it work if possible!
Re: twist advice needed - goaliedad - 03-05-2016
First, I would not cut the kerf's all they way thru the ends, make them like blind dado's instead.
How much of a twist are we talking? if you lay the piece on a flat surface how high does the one corner raise up?
Given the weight of the legs, would the twist be enough to distort the final table? or will the legs be heavy enough to hold it flat? Not the "right way" to deal with it, but if the twist is minor, it might work??
Re: twist advice needed - DonJuvet - 03-05-2016
My thoughts on natural slab tables.....
They have a certain elegance in the "not perfect'
aspect of their being natural slabs.
I have built a table that had a crotch end in it.
It had a WONK. The wonk has the best figured grain. The biggest test... Will a full wine glass tip?
I built another table with a bookmatch pair. They were stored for a long period of time in the rafters of a barn. No center support. One bowed up, one bowed down.
The customer will get a nice story to go with the table.
Natural design element. It is what it is.
Sell the natural feature of what wood does and Not Messing With It.
Planing it to 7\8" thick may not have been the best move.
But, that's done.
With it being that thin now. The Goalies Dad may have a point. A lot of weight in the base may make a difference.
Re: twist advice needed - Steve N - 03-05-2016
Possibly not what you want to hear, but if this table will see regular, or especially heavy use I would look for some new flat lumber to start with. I only say this from past experience where starting with a thicker piece of twisted, cupped, bowed, and crook stock. Always seemed to end up much thinner, and a whole lot smaller piece of wood than when I started.
That said you could do the kerfs, it will be an unknown about strength until after you complete, but it isn't something you do on the normal schedule of prepping stock. So YMMV. I would source new wood for the top.
Edit to add acceptance to Don's point about embracing the imperfect, also agree you went past that point on the typical live edge table. I am more from a flat table point of view, and the imperfections I like are Cherry gum streaks, nice solid knots, and that terrible curly grain
Re: twist advice needed - pinky - 03-05-2016
The legs will be plenty heavy but the plates I mount will stop 6" short from each side and the end. If the kerfs stop short of the ends will that still allow the sides to drop a little?
Certainly not slabs anymore... 2 bookmatched wide boards
Re: twist advice needed - JGrout - 03-05-2016
the only way I see you finding out if the legs are heavy enough to overcome the twist is to mount the top while on a flat surface and see if it holds or rocks
there is little reason to cut it up trying o overcome the twist if it does not require it
Joe
Re: twist advice needed - Gary G™ - 03-05-2016
The twist may be little enough that a small shim on the bottom side where the high spot meets the top of the legs will solve it.
Re: twist advice needed - Bill Holt - 03-05-2016
I have used the kerf idea on the bottom of a blanket chest and it worked but in that case the bottom was supported on all four sides.
At 7/8" the top may be too large for deep kerfs. You might consider using a metal plate long enough to pull the corner down. (do I make sence...not sure)
BTW you have a beautiful chunk of wood there! Best of luck.
Re: twist advice needed - Phil S. - 03-05-2016
That is a awful pretty top! Any chance you have clamps with deep enough throats so you could clamp the top to the bases and see how that goes. If it doesn't take a lot of force to pull it together I might be comfortable just depending on the fasteners to keep it flat, but I'd be a bit concern about the fasteners pulling out if it continues to warp and perhaps more concerned about coming up with a plan to deal with future seasonal movement of the top. Are the holes in the bases slotted to allow for some expansion and contraction in the width of the top?
Re: twist advice needed - RPE1 - 03-05-2016
I built a 53'x53" solid walnut table a few years ago. I made it in three 18" sections. It was dead flat. I took it to a cabinet shop and ran it through their three belt drum sander. I took them home. I had to work and had to drop what I was doing. When I got back to working on it a few weeks later the tops and curled.
What I realized was the top sections were laying on solid surfaces. The tops were acclimating to the ambient conditions and the bottoms weren't. When I set them out on saw horses, so both sides of the top could air out, they flattened out after a week or so.
I don't know how you are storing your top, but this might be the case.
RP