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Forum topic by amdepalma posted 05-13-2017 03:02 AM 955 views 0 times favorited 5 replies Add to Favorites Watch
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amdepalma

7 posts in 593 days


05-13-2017 03:02 AM

Hi fellow woodworkers,

I am new to slab woodwork but have a client who wants a waterfall edge slab console table. I have concerns about keeping it flat over a long period of time and was thinking about recessing 1/4” pieces of steel underneath across the grain to keep it from cupping. Is 1/4” thick enough or too thick?

Also, anyone have any advice on how to efficiently cut slotted screw holes in a piece of steel that thick so when I screw them to the slab the wood will be able to expand and contract?

Thank you!!!

Cheers,

Andrew


5 replies so far

View EricTwice's profile

EricTwice

230 posts in 371 days


#1 posted 05-13-2017 03:36 AM

If you are talking about laying them flat, the short answer is no

If it were 1 1/4 by 1 1/4 angle that is 1/4 thick it might stand a chance. Use slotted holes to let the wood move.

Be sure your wood is dry and and do not try to pull it flat with the iron. You must work it flat either by hand or machine. (Your best bet would be to let the wood rest in the stick for five or six years before use. this gets rid of some of the internal stress. But most of us don’t have that luxury.)

once it is flat and true build from there and finish both sides the same. the finish can cause it to warp. The iron is just insurance. Hope it isn’t needed.

-- nice recovery, They should pay extra for that mistake, Eric E.

View amdepalma's profile

amdepalma

7 posts in 593 days


#2 posted 05-13-2017 04:12 AM

Hey EricTwice,

Should have clarifed….I will flatten with my router first. I am just trying to come up with a way to insure that it stays flat with seasonal expansion and contraction. Does that change your opinion on 1/4” thick steel keeping it flat?


If you are talking about laying them flat, the short answer is no

If it were 1 1/4 by 1 1/4 angle that is 1/4 thick it might stand a chance. Use slotted holes to let the wood move.

Be sure your wood is dry and and do not try to pull it flat with the iron. You must work it flat either by hand or machine. (Your best bet would be to let the wood rest in the stick for five or six years before use. this gets rid of some of the internal stress. But most of us don t have that luxury.)

once it is flat and true build from there and finish both sides the same. the finish can cause it to warp. The iron is just insurance. Hope it isn t needed.

- EricTwice


View Rick_M's profile

Rick_M

10634 posts in 2218 days


#3 posted 05-13-2017 05:50 AM

Wood movement is hydraulic, it’s very powerful. 1/4” steel will work against wood movement but depending on the size of the slap I wouldn’t count on it for prevention. Screws will be the weak point. Best bet is proper drying, flattening after it has reached equilibrium, and then finishing both sides equally to retard moisture.

-- http://thewoodknack.blogspot.com/

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EricTwice

230 posts in 371 days


#4 posted 05-13-2017 01:18 PM

I am just trying to come up with a way to insure that it stays flat with seasonal expansion and contraction. Does that change your opinion on 1/4” thick steel keeping it flat?

- amdepalma

If you are laying it flat, the answer is still no. You can deflect 1/4×2 steel with very little pressure You are better off with a piece of angle. I have also used wooden cleats cut from matching material with good success they are less visible. Whatever you use be sure the top can move or the pieces you put there to keep it straight will warp it.

If it is dry and you have it flat, It should want to stay that way unless you put uneven pressure on it with your finish. Most of the slab stuff I’ve done is walnut and cherry.

(On the other hand I just completed a table. top is 9’ x 3’ 1inch thick hard maple. grain runs end to end. top is three pieces cut from the same boards with grain matching. the center leaf is 2 feet long and cupped more than an inch. the end pieces did not warp at all. I glued up the top in 1 long piece and cut it into 3 sections to have perfect grain match. why did the center warp and not the ends? I do not know. All received the same treatment. Nor, do I know how to make it stay flat. Sometimes wood is like that.)

-- nice recovery, They should pay extra for that mistake, Eric E.

View tomsteve's profile

tomsteve

667 posts in 1057 days


#5 posted 05-15-2017 04:10 PM

i think most slab wood tables have some sort of metal frame- square tube or angle.
for cutting the slots, find a metal working machine shop with a mill

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