unisaw + DJ20 issues -- suggestions?

[Philip DiPaolo]

hi --

not long ago i moved into a shared shop space which the owner built, and furnished with tools he bought from a tool collector buddy. he hasn't had the time to do any tuning or maintenance after building out the shop, and working.

now we're trying to get the 1980's unisaw and the DJ-20 8" jointer tuned + aligned. the other major floor tools are OK -- the planer and drill press are new, and the bandsaw is a used 18" jet in decent shape, with no problems so far.

we three shopmates are novices in tuning machinery, but we're trying. on the uni, we made new faces for the biesemeyer fence, aligned the miter slot to the blade, and aligned the top and fence to that -- all to within a couple of thousandths.

but still the cuts we get are ever so slightly wavy, though straight overall. so i took a good straightedge to the table, and it's noticeably dished within about 6" of either side of the blade path.

so we made a new insert, and tried new blades, but still the cuts are still slightly wavy. plus, the saw is screamy and loud -- seems louder than it should be.

the 8" DJ20 jointer has a few issues too: the outfeed table is worn at the cutter head area, and sags at the very end.

the jointer fence only holds itself square for a few cuts, and it drags on the infeed table. sometimes we can get good cuts, but it sure is a hassle, and unreliable to have to keep checking for square every few cuts. (it almost seems like the blade guard knocks into it, and kicks it out of square.)

so, my questions are:
-- are these things fixable, and how easily?
-- what to fix first, and how much should he expect to spend?
-- do we have to get the tables reground, and is that even worth the cost?
-- what can we do about the unstable jointer fence?

thanks in advance.

--------------------
cheers,
philip

[Greg Sznajdruk]

If you are referring to a wavy cut during rip cut, then I would suspect your fence and not the table. Take the straight edge to your fence and see if it is straight.

Greg

[David Carley]

On the Unisaw, have you tried running the saw without a blade? The screaming is almost certainly being made by the blade, but it would be good to validate that assumption.

Is the blade you're testing with new? If not, try a fresh blade. If that doesn't fix the issue, it's possible that the bearings are worn and you're getting "wiggle" in the arbor. With the saw unplugged, see if there's any play in the arbor by pushing/pulling on the blade, perpendicular to the arbor.

The dishing you mention on the Unisaw's top isn't a great thing, but shouldn't produce a "wavy" cut -- it might affect your ability to make square cuts, however.

On the DJ20, you say "worn", but give no scope on the magnitude of the wear. Are we talking a few thousandths, or is there cupping of the bed on the order of a 1/32" or more? As for the sag, is there any evidence of "blunt force trauma"? (ie: Did some bloke drop something _big_ on the bed?)

I'm not sure what kinds of cost you'd be looking at to have the bed reground, but I'd think it'd be worth making a couple of phone calls to local machine shops, or asking the local woodoworker's club/guild if anyone has the capability.

As for the fence, if I remember right, the DJ20's fence has a cam-lock mechanisms? Have you checked that everything is clean of oil, grease, rust, sawdust, etc?

-David

[Philip DiPaolo]

hi --
these are all good suggestions, thanks. haven't been back in the shop yet because regular work kept me away, but i will post back here when we find some answers.

cheers!
philip

[Pete Bradley]

Exploded views and parts are available on the Ace Tool Repair website. I've bought from them successfully. The biggest pool of expertise that I've found for these kinds of questions is the forum Old Woodworking Machnes website: http://www.owwm.com/

Pete

[Jake Helmboldt]

As for the DJ20, it has parallelogram beds, so adjusting that sag is, in theory, much easier than shimming a traditional jointer with dovetailed ways. I say "in theory" because everyone touts the adjustment of the parallelogram beds, but I've heard it is not so simplistic. None the less, there are adjustment features to address the problem, but it would require that the table is at least flat.

[Greg Ladd]

Philip,

As others have said......

Recheck the table saw, making sure that you reference a specific tooth on the saw blade. I usually mark one tooth with a black marker. Verify that that miter slot on the right side is absolutely parallel with the same tooth with the blade rotated to the front and then the back.

Take your time with this as it is critical to an accurate set up. With patience you should be able to get it accurate to within .001.

Once that is done, set up your fence with the outfeed side .001-.002 away from the blade. This set up will give you straight cuts with virtually no burning and a greatly reducing the risk of kick back.

Also, make sure that the face of the fence does not have a dish in it from the front of the fence to the back. This is not uncommon and can lead to exactly the problem I assume you are having. As you push the board down a fence that isn't straight, the board will follow the dip in the fence and will then wander away from the intended cut line.

The jointer tables can be made coplaner by adjusting the cams that the tables are fastened to. There are four cams on each of the infeed and outfeed tables. Make sure that the infeed and outfeed tables are coplaner to each other when you get done. The outfeed table should be the same height at the knives at the top of the cutting arc when you are done.

I am guessing that most of your issues are being caused by the jointer tables being out of adjustment rather than worn. I think if you set them up correctly and use good technique when jointing you will get much better results.

The jointer blade guard spring can be adjusted to lower the 'strength' with which it swings back. I do not recall at the moment how that is done. I have mounted a small rubber bumper on mine to keep it from banging into the fence but the fence should not be knocked out of alignment by the blade guard. The DJ20 fence has a fairly robust indexing system. Make sure there is nothing broken there. If I recall there is a spring loaded shot pin type assembly that indexes the fence at 90 degrees. I would be very surprised if the blade guard is the culprit.

The fence is designed to rub on the table. This allows the bottom of the fence to be on the table when the fence is tilted to the 45 degree position.
Hope this helps,
Greg