Jointer (dovetail ways) not co-planar
inexile
| Posted in Power Tools and Machinery on
6″ Jet Jointer, three years old and never turned up, is not co-planar.
A 12” starrett, laid across the beds close to the fence (back of the jointer) allows for an .008 feeler gauge.
Laid across the beds away from the fence (front of the jointer), I can’t even fit a .0015 gauge.
And the slope is constant with a .004 feeler gauge sliding in at the center.
Is there an easy way to adjust this? Do I need to remove the infeed table and clean out the ways (which look pretty funky)?
Replies
I don't think you have much option.
It is not usable with that much droop - you'll get significantly bent boards. I don't work in imperial, but allow for less than the thickness of a sheet of paper (about 0.003 I think) - if the paper will pass, the planer doesn't.
I would clean and check the ways for dings - very small bits and raised areas can have a significant effect. If that does not work, you can probably shim them, but I have no personal experience of doing that.
I would reference the manual if that doesn’t work,I would give the folks at jet a call and see what they have to say before you dig into this.I HAVE A 1950S Delta 8 inch that I had to shim up and I day a real pain in the butt.
I looked up your jointer and it’s supposed to have gib screws so you will need to use those to make adjustments per the manual.
Jointers are fairly basic machines. It is unfortunately easy to get yourself in trouble if you start adjusting things without knowing what your reference point is. I would give this a quick watch before I started moving things:
https://www.finewoodworking.com/2018/07/30/ep-3a-machine-setup-jointer-part-1
The tables align in plane with the cutterhead (not the knives). Your tables can be aligned with each other wonderfully but be misaligned in relation to the cutterhead. Grizzly gives some instruction on cutterhead alignment here:
https://www.youtube.com/watch?v=3caxVqv3FyU
Once aligned, John White discusses table heights here:
https://www.finewoodworking.com/2008/07/01/adjusting-a-jointer
Your straight edge should be longer. You don't have to go big-bucks on this. Accurate within about a thou over 3 feet is fine. Plenty of people align their jointers with a well milled piece of wood. Of course if your only accurate milling machine is the one you are trying to align there's a catch-22.
/QUOTE/
"A 12” starrett, laid across the beds close to the fence (back of the jointer) allows for an .008 feeler gauge.
Laid across the beds away from the fence (front of the jointer), I can’t even fit a .0015 gauge. "
/END QUOTE/
Are these measurements between the Starrett and the knives?
Thanks - I have a longer straight-edge on order. In the meantime, I completely disassembled the machine, cleaned out all the gunk (there was a lot), lubed the gibs/ways (and other critical parts) with white lithium grease, and put it all back together again. Also rotated every one of the helical cutters - this was needed! Everything is now coplanar and square, and I'm getting a handplane-like finish off the rotated cutters!!
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