Proper way to flatten a workbench top

[Jeff Heath]

To add to what's already been stated above.....

Assess your bench first. You need winding sticks. Measure how far it is out of flat, or how much twist or warp exists, if any. As stated, mark the high spots, and measure how much material you need to remove to get it flat. A shop made straight edge will work wonders.

There's no need to go after it with a heavily cambered iron in a scrub or jack plane if you're just a little off. You won't know until you assess. Getting after it blindly with a heavily cambered scrub plane might create more work for you than you already have. You won't know until you measure/assess.

I don't even own a scrub plane. Nothing against them, but I like the heavier, longer jack plane with a cambered iron. Same thing, just bigger.

In a perfect world (which does not exist) you'll only remove the high spots, and finish up with a #7 or #8 lengthwise to smooth everything out in the same plane, within reason. No need to make it look like a $20K dining room table top unless you're "that" anal. Then, have at it....whatever makes you happy.

[george wilson]

Sometimes when you flatten a warped board,it stress relieves it even more,and it warps worse.

You might try thoroughly WETTING the CONVEX side. When it dries,it pulls the board flatter than it was. I know this seems counter intuitive,but the furniture conservation shop did that all the time. They would have a table top that was out of flat,but they wanted to preserve the ld varnish and patina. of the top side was the hollow one,they would wet it like that.

I even saw them put plexiglass over the water,to give it more time to really soak into the wood. They would leave the plexi on the convex surface for WEEKS sometimes. Then,when they removed it,the 200 year old wood would have a better chance of pulling flat.

Bringing antiques over from England caused all kinds of trouble from the change in climate. Tall case clock door frames ( the kind with glass in them so you could see the pendulum ) ,were among the very worst problems. Doors with loose panels in them were just as bad.