Router table-flatness???

[Jay Yoder]

I am loooking at buying a prefab router top. One is .030 out of flat along length and width and the other one is .035 off in the length only. How much difference will this make? Any thoughts?

[glenn bradley]

Are you measuring while they are mounted? .03" ( I am assuming you mean inches) is a skinny 32nd of an inch. I would not want to try to get a good fit on a sliding dovetail or a cope and stick profile with 1/32" of error. Are you sure you don't mean .003"? That is thinner than a sheet of typing paper and I could work with it. The reason I ask if you are measuring while they are mounted is that torquing the top to your frame can do some good or bad things for a table top. If the .03" is unmounted, I would feel that I could shim that out with a good supporting frame and mounting method.

[Jay Yoder]

These tops are clearanced at a local supplier...No clue which direction, just stanted as .030 and .035...maybe their ad was wrong?

[Bob Wingard]

1/32 isn't ideal, but it's not horrific either. Forget about the entire table surface, and concentrate on where the work is being done. The rest is simply support. IF you had a severe dip or hump right at the bit, I'd be concerned .. otherwise, no big deal.

Technique is more important here than perfect tooling. IF you made a cope cut on some frame & panel pieces, and the profile wasn't a perfect fit, you would simply adjust the mating bit's shims to get a good fit. With feather boards/hold downs/push blocks, you should never have to worry about the perfect flatness of your table right at the point of contact with the bit. If your table sagged 1/4" along the entire length of the fence, you could still get perfect fits on cope & stick cuts.

Another option would be to analyze the out of flat condition, and determine if the top can be pulled or pushed into flatness with judicious use of under table supports.

I had a brother who was a Tool & Die maker. He had NO woodworking equipment, but he had a lathe and a mill in his shop. I loaned him all the tooling & cutters he needed, and he built some cabinets and 5 panel doors, using his mill. The fit of his joints was as good as my old router table, but no better. We laughed about the 'till he died a few years ago. As the old timey drag racers used to say .. .. "Run what you brung, Sonny - it's all fun".