DJ20 Jointer

I had a very good Delta 6" jointer, but soon realized how much more useable an 8" jointer would be. Did some research, asked some friends and decided that a Delta DJ20 is the best 8" I could buy. It's got the longest tables you can get, but what really sets it apart from any other 8" jointer is it's unique parallelogram design. This design is unigue and is far superior to the gib design on all other jointers in it's ease of use, and ease of adjustment.

The DJ20 is much larger than the 6" jointer it replaced, but this picture manages to make is look small ;) The challenge of finding room for a new machine in a small shop is always harder than the purchase and paying for it. This extra long 8" jointer didn't want to fit in the spot the smaller one occupied, so I built a new spot for it. I used the last two 7' pieces of ¼"x2" steel angle that I accidentally bought last year for the bed frame. I used the first two on the CMS stand I built and still had these two lying around. Seven feet is a magical length, just right for my CMS stand and perfect for this jointer. Like the CMS stand, it's basically a ladder with two long pieces joined together with four 30" pieces of thinner steel. I threw on a piece of 1/4" masonite and then attached a few pieces of 2x8 soutern yellow pine that were left over from another project and were just stealing valuable space. The masonite is just to prevent anything from slipping through the spaces that will eventually form between the 2x8 and falling onto the jointer. It's lag bolted to the wall and supported in from by those two 2x4 legs in front. The span between the legs is quite a bit, but the ¼" steel will resist sagging. The legs are placed in such a way that it's remarkably easy to move the jointer in and out on the mobile base. The mobile base on this DJ20 is just great. I step on the pedal, push it to the left about 4", pull the infeed table towards me allowing it to pivot on the wheels on the left side. Just as the outfeed table approaches the wall in back, the jointer is angled perfectly to slide out from under than bench. Putting it back is almost as easy.

This jointer is heavy, real heavy.  It will take at least one other person to help you assemble it. It comes in two crates, the cabinet with the motor inside and then jointer itself.  Don't bother trying to lift anything out of the crates. Just disassemble the crates.  If you bought the mobile base for it make sure you put the cabinet on the mobile base before you put the jointer on the cabinet. Trust me on that.  If you don't have the mobile base and think you'll get one at some point, then get it now, you won't want to lift the jointer and cabinet together onto the mobile base.
Never lift any jointer by the tables.  Hold onto the main center part of the jointer.  Remove the thick waxy/oily cosmoline from the cast-iron using kerosene or WD40 in a clean rag. Never use gasoline. Dispose of the rags properly you don't want them to catch fire in the trash can.

All jointers need fine tuning from time to time, and it's well worth learning how to do. The beauty of the DJ series is how easy it is to make adjustments. Still, you have to understand how it all works to benefit from the ease of tuning. Plus there are a few tricks.

I plan on posting more information on the DJ20 soon.... in the meantime: A couple of friends sent me some information on tuning a DJ20. It originally came from a fax that was sent by Delta/Porter-Cable. I am working on enhancing the instructions with color photos and stuff. But it's taking me a while. Here is the work in progress including the original B&W photos.
DJ20 Adjustments

The best feature of the DJ series jointers is how easily the tables are adjusted.  But it took me a while to figure out what too use to turn the eccentric bushings once the hex screws were loosened. First, make sure you loosen BOTH hex screws (there are two in each hole, stacked on top of each other) that hold the eccentric bushings in place. Then to turn the bushings, use a small pair of needle nose pliers.  Open the jaws of the pliers and fit the tips into each of the two holes on the face of the eccentric bushing.

The jointer is and has to be the most precise machine in your shop.  Even more precise than your tablesaw or planer. Invest in a proper straight-edge for tuning. Highland Hardware sells a 36" Starrett Straight Edge for about $100.  It's worth every penny.  A level or anything else like that just doesn't have the accuracy required for jointer tuning.

You can spend too much time fiddling with the adjustments on a jointer.  At some point you've got to say, I've got it a close to 0.001" as I can.  The easiest way to check to see when it's adjusted correctly is to TRY IT.  Simply edge joint two hardwood boards and them hold them edge to edge.  If you've got a gap anywhere then you know you've got some more tuning to do.

When checking the height of the knives, makes sure you check all the knives.  I initially only checked the height of one knife and then discovered that it wasn't jointing properly. Then I discovered that one of the three knives was higher than the rest.

I had a little trouble setting the knives correctly the first time I tried. I found there is some tricks to fine tuning the cutter head and knives. This is what I did:

  1. Loosened 4 bolts on knife gib and removed gib.
  2. Removed 4 bolts
  3. Placed each bolt in the drill press (hand tightening the DP chuck so as not to damage bolt threads).
  4. Polished the bolt head with 220G sandpaper for 2 minutes and 400G wet/dry sanderpaper for another minute.
  5. Placed knife side of gib down on 220G sandpaper on a plate of glass and flattened the gib face.
  6. Finished making the gib shiny and flat using 400G wet/dry sandpaper on the glass, lubricated with spit ;)
  7. Sprayed gib and 4 bolts with WD40 to remove any remaining moisture (spit) and screwed 4 bolts into gib.
  8. Dryed up the assembly with paper towel
  9. Cleaned the slot in the cutter head with mineral spirits.
  10. Cleaned the knife the same way
  11. Lowered jackscrews in cutterhead.
  12. Placed gib into cutterhead
  13. Inserted knife into cutterhead.
  14. Pre-tightened 4 bolts (front, back, middle, middle) pretty tightly.
  15. Placed machinest square on outfeed table and turned jackscrew up until blade barely touched the square.
  16. Tightened 4 bolts fully
  17. Repeated for each of the other blades.

There were two secrets. One was to have the bolts pretightened enough to prevent slipping of the knives during the final tightening. But in order to do that, I needed to polish the bolt heads and gib face which allowed adequate pre-tightening of the 4 bolts. Before I did that, I had actually pre-tightend the 4 bolts less and still couldn't get the jackscrew to bring them up... they stuck. By polishing everything, I was able to pre-tighten more and still the knives would respond to the jackscew.

Hope this helps!

© 2008 Mark Goodall