Thread: How flat?

Bob, If its a bench , a work bench for woodwork , then it should be flat . No two ways about it ! With a square edge at the front off that . If you had dog holes and a tail vice , even more flat ! A twisted bench top is only good for cleaning and washing things on not clamping to and planing ,or clamping to and assembling things on .
Use winding sticks and a long plane . Get it right and all you work will be true from that point on . Cheers Rob

Agree - if you use the bench to assemble your work any inconsistency will end up being transferred to your work. I personally don't have the skill or patience to work within fractions of a mm so to some degree I'd argue the final level of flatness will be a matter of judgement. That said, the 3mm amount you reference should be addressed

Bob,

Yes it should be flat.

When I built my bench top after the glue up it had a twist in it of in excess of 5mm.
Ending up building a router sled and flattening it that way. The router sled was 1.2m wide and the rails 3.0m long.
Took a day and a bit to build the sled and test it. Then a morning to flatten the top.

This it the thread of my bench build and router sled.

Another Bench

Because as you say it is a "tool" it does need to be flat and true.
My workbench has no pretence of beauty,it is welded steel painted black with a 20mm thick melamine coated particle board top.
when too worn and marked I will just replace the top.

Thanks everyone.

I don't have a long plane and am wary of router sleds after a previous experience so it's going to be a "flat as I can get it" bench top.

Have already been back at it for some hours and it looks like it's half way there.

Which means it's probably about a quarter of the way there.