Jet JJ-6CS jointer knife install questions

[Davee Baker]

I'm putting new knives (blades?) in my Jet JJ-6CS jointer. Had a heckuva time getting set screws out but thats another story (maybe). My question is how should the blade holding bar be installed ... top curves down or top curves up toward knife edge? It came apart with top curving down towards knife so I'm inclined to do that but that's not in agreement with the picture in Owners Manual or any of the drawings I see other places. Also ... the set screws are not perpendicular to bar, they are oriented at a slight angle. I think the angle is reflective of the slot, which has sides that are not parallel, more of a wedge. So it would make sense (to me) if the set screw angle corrected for that and ended up putting the set screw head aligned with the slot face that it drives into. But if I put it together the way it came apart , it would be the opposite of that. Again (said another way) should the bar have the taller side or the shorter side against the blade (knife). I could take pictures if that helped but I think this explains it. Since the screws are not perpendicular to the bar (chipbreaker?) ... why is that? It seems to make more sense if the bar was installed the opposite way than I took it apart. But the bar is tall enough that there would only be 1/16" from top of knife edge to bar which seems wrong! Thanks for any help, new member this is my first post!

Just wanna do it right and also understand why parts are like that.

[Davee Baker]

OK, nobody replied ... I guess I'll reply to my own thread! Almost all of the 12 knife screws would not come out and some were getting stripped hex heads trying (yes, I know clockwise to loosen knife) so resorted to cutting heads off with Dremel. I thought they were corroded (used PBlaster) and stuck but the last guy must have way overtightened them creating a lot of tension in the cutterhead. As soon as I got a few out then the rest free'd up. Then I found out you really can't buy these anymore & the advertised price is $5 or so a screw (and not in stock anyway). JC-C06 is then P/N. Replacement is a square head, which is far superior. My only option was to buy a bag of 1/2" inch long screws and cut them off to fit (1/4" length). Once I figured out what the name of that fastener was I found them in stock (ASMC) and bought a bag of 25 1/4"-28 x 1/2" (FT) Fine Thread Square Head Set Screw Cup Point Low Carbon Steel Case Hardened Plain Finish. It was fairly easy to cut to length with Dremel and then fix up thread ends. Used the "put a nut on first" trick. They work great! I also taught myself how to make the tables coplanar by shimming outfeed table and the whole process of installing knives. Had to buy a 38" precision straight edge from Woodcraft, good product. Tried one of those magnetic jigs from Woodcraft but it was defective and had to take it back. The only other one they had was defective also. Plastic Garbage. I ended up using some red oak strips with weight on top to initially install at outfeed table height (+.0001) and that worked fine once I worked through a few issues. I had a dial indicator on a base I bought from a retired machinist. The dial indicator and some tapping adjusted blades to final position. Kept taking blades out and putting them back in until I got proficient at it. Four times. Found new knives at Home Depot (of all places) for about $10 a set. Jointer had some serious rust on tables but I mechanically removed that (wire wheel etc) and then used the Boeshield rust remover (phosphoric acid) and T-9 to make tables nice again. Bought & built a Bora Portamate mobile base, which is quite convenient in my "workshop". Noticed that the belt gets really hot! Probably should order one of those. Belt is from 1992 .... I think that's kind of old and rubber starts to be less flexible so heat buildup. Jointer is lookin good. Now I just wish I was better at using it. I'll have to work on that next.

[Charlie Jones]

Knowledge gained the hard way usually sticks.

[Meryl Logue]

Thank you for the follow-up.