Hey Gary,

I apologize if this has been asked before…I did try to search previous posts, but didn’t find the specifics to my question. I have a question regarding the proper technique for checking table flatness. Sorry, I lack the engineering background to fully comprehend all the means, averages, variations, etc. when checking tolerances.

I’m new to woodworking and recently purchased a 8″ jointer, as well as a straightedge to get the machine dialed. Everything I’ve read states to place a straightedge on the table and using feeler gauges, check the gaps along the surface. I believe in your article you stated you should check any length on the table, and it should be somewhere around .002″ or less. The manufacturer’s also states their tolerances are .002″/foot. To be fair to the manufacturer, I want to make certain I understand this correctly. I also, don’t want to keep a machine that’s outside of the manufacturer’s tolerance, only to find out after the warrantee has expired that I can’t return it.

I have a 3′ Veritas straightedge which I placed on the table. If I place the straightedge to the rightmost part of the infeed table, I can look under the ends of the straightedge and visibly see gaps. Should I only be placing a feeler gauge under these gaps to check the variance, and do I add these gaps up to determine whether I’m within tolerances…so along a 3′ run, I should not see a sum of more than .006″?

or…should I hold down one of the ends to keep one end of the straightedge flat against the surface, and allow the humped table to “rocker” the straightedge, and measure the gap under the opposing end, which in this case happens to be more than .010″.

This seems to be outside of the manufacturer’s allowed tolerance.

Or am I to assume that when I lay the straightedge on the table, and it’s sitting flat, I should assume that’s the mean measurement, and the gaps are to be .002″ or less each foot in either direction?

Thanks for your time,
Tom