Jointer table flatness

[DaveH]

I bought the 6" Ridgid jointer the other day. Upon assembly I have found that the infeed table is convex across the 6" width (the center is about 0.0025" higher than the edges). The outfeed table is concave (the center is about 0.0035" lower than the edges). The net result is that, for example, if the tables are set at the same height at the center, the edges of the infeed table will be about 0.006" lower than the outfeed table. This distortion does not extend the full length of the tabls as they are perfectly flat towards the ends.

Is this sort of distortion normal? Is it within acceptable tolerance? Should I be returning it to HD and demanding a replacement.

Thanks,

Dave

[George]

The board is entirely different after it passes over the cutterhead, so the in/out differences you noted are differences which make no difference. The concavity in the out _might_ give a bit of snipe. Run a few pieces and see.

[Never Enough Money]

How did you measure that the 0.0025 and the other measurements? Whatever you used must be a lot more accurate that that. Starrett straight edges are 0.0001 accurate per foot of length. Many others are

0.001 (one less zero).

DaveH wrote:

[DaveH]

With a 6" staight edge that I verified as straight along the length of the tables at various points. I then placed this straight edge across the width of the outfeed, immediately after the cutter, and could see visible light under the centre. I measured this to be 0.0035" with a feeler. The same straight edge placed across the width of the infeed, just before the cutter, rocked. Using a dial indicator and stand I set the tables level at the fence side of the cutter. In the centre of the cutter I measured a 0.007" height difference and at the other end a

0.002" difference.

Now I realise that my technique and instuments may not be ideal which is why I qualified my original measurments with the word about. I didn't, however, expect to be able to measure ANY distortion in the tables.

[Daniel Marks]

replying to DaveH, Daniel Marks wrote: I have been a machinist and also have been in Quality in machine shops most of my life (I am old BTW), While I cannot find the acceptable specification generally across flatness within .003 inches will not affect the flatness or squareness of the product produced on your jointer. I would believe that .003 or less would be considered within specification at the factory as well. That really is pretty flat for a ground surface. It is not aviation quality perhaps, but fine for making great flat and square boards.

[Jay Pique]

"Pity the woodworker that ought to have been a machinist"

- Someone