Jet JJP-12 Jointer/Planer coplanar adjustments

[Jerry Junkins]

I have the Jet JJP-12 and I like the idea of it but I don't like the fact that every time you lock the tables down, the alignment with the blades changes. Depending on how hard you lock it down, you could vary as much as .010", which in my opinion is way too much. One would think that you should be able to adjust the front two bolts and once the table contacts them they would be solid, but it is hard to get the two bolts exactly right so they both contact the table at the right time to prevent rocking between the two. The two front adjustment bolts are very sloppy and it is almost impossible to fine tune the tables, in my opinion. Has anybody done a coplanar alignment on this machine? I would appreciate any information on adjusting the tables. I have ordered a 50" straight edge from Lee Valley and that should help the process go more smoothly. Any info would be appreciated. Thanks in advance.

[Curt Harms]

.01" doesn't seem like much. It'll be interesting to see what others have to say. I have that machine as well and as long as I can joint two boards, hold the jointed edges together without clamping, they lay flat and there's no light coming through, I'm not going to worry about it.

[Vic Barton]

I had to rebuild mine after flood damage shortly after I got it. I ended up replacing those front adjusting bolts. I've never measured for any difference, but my boards come of flat and true.

[John Coloccia]

Anytime you move the front adjusting bolts, you also need to move the lock mechanism. If you move the bolts without moving the lock stud, you can make it either ridiculously loose or ridiculously tight. I have mine set so the the handles are straight down when everything's tight. I define tight as "feels like it's not moving to me!" You can see the stud as you lock it down and get a feel for how much you're deforming it.

It can be a little bit frustrating, but I can tell you that I go back and forth between planing and jointing without any problems. The way it adjusts and locks, though, could definately have been designed better. If I were designing it, I think ideally the locking stud would have been the coplaner adjustment as well. "Locking" would have been a simple matter of a cam that keeps the stud from lifting off of a stop, and then all these problems melt away.

C'est la vie!