Hello,
I spent the weekend tuning up my shop and I purchased a the polycarb jointer jig with magnets from Woodcraft to reset my knives. I have a Sunhill jointer (like Jet/Grizzly, etc) and the knives are held in place with a magnet piece that has screws that bind the knives/magnet into place in the cutterhead. The two pieces sit on a couple of springs (I assume to help align the knife).
One thing I noticed is that the springs were so strong that the knife assembly pushed up on my magnet jig. So I ended up lining up the jig first (on TDC - true dead center) and then putting a block on top of the jig to hold it down, sliding the knife assembly underneath so the tip of the knife lined up with the mark on the jig and then secured it.
Once I installed all 3 knives I did the board slide test (as described in the archives). I put a mark on the board, set the board on the outfeed table, over the cutterhead as well, and lined the mark up to the end of the table. As I rotated the cutterhead (using the belt) I found that one knife moved it about 1/8", the 2nd knife about 1/16" and the third just barely touched it. Oh, I should probably point out that I aligned the outfeed table to the first knife before checking the other three (hoping they would match). So at this point I do get nice flat boards when run through the jointer, but logic says one of my knives is working harder than the other 2.
So, since I'm not really using the magnets to set the knives (I have to push down on the jig to keep the springs from pushing the jig up), it's acting as more of a flat hold down. Ugh.
Here's my question: Is it possible to remove the springs without affecting the performance of the jointer? By removing the springs it seems that the jig would perform as it was designed -- to hold the knife assembly UP not push it down -- thus I would be exerting less pressure on the knives and I assume I would be able to align them more precisely.
Or do I just keep aligning them over and over until they match with the push test? I'm I dreaming that that's possible?
Thanks, Mike