Brent Ring
02-25-2009, 3:15 PM
Okay, after I explain what happened and what I did, I am sure someone will tell me to get a better straight-edge - but it worked for me. I have a bed project going right now and needed to plane some long boards for the headboard and rails. I decided it was time to change the jointer knives to sharpened ones. I have a 6" Jet jointer with around a 40" bed.
I took out the old knives and installed the new ones, and used a 12" straight edge from my combo square to adjust the knives to the correct height. I started edge jointing a project board and noticed I was getting rocking. I had correctly setup support for both infeed and outfeed, but was still getting rocking occurring. I got frustrated and quit for the day after maiming one board.
As usual, I came back to the creek to check out my technique and other ideas. Chip Lindley has "rassled" with some long boards on a 6" jointer.
Well the only thing that had changed was the blades, so this time I got out the 24" framing square, set it on the long edge, and held it in place with a wooden handscrew. I then loosened and re-adjusted the knife heights. Once tightened I took a few test passes with a practice board and sure enough, nice flat, perfect jointed edges.
I share this only to show that when the right type (Length in this case) of tool is used, things get adjusted and work just fine.
This makes me question the things like the jointer pal, which is set up to make jointer knife installation faster and more accurate. I probably have a bad 12" combo square, it not an expensive one, but I wonder how these short little devices can do such an accurate job?
Anyway, a little FYI and information from my recent shop time.
I took out the old knives and installed the new ones, and used a 12" straight edge from my combo square to adjust the knives to the correct height. I started edge jointing a project board and noticed I was getting rocking. I had correctly setup support for both infeed and outfeed, but was still getting rocking occurring. I got frustrated and quit for the day after maiming one board.
As usual, I came back to the creek to check out my technique and other ideas. Chip Lindley has "rassled" with some long boards on a 6" jointer.
Well the only thing that had changed was the blades, so this time I got out the 24" framing square, set it on the long edge, and held it in place with a wooden handscrew. I then loosened and re-adjusted the knife heights. Once tightened I took a few test passes with a practice board and sure enough, nice flat, perfect jointed edges.
I share this only to show that when the right type (Length in this case) of tool is used, things get adjusted and work just fine.
This makes me question the things like the jointer pal, which is set up to make jointer knife installation faster and more accurate. I probably have a bad 12" combo square, it not an expensive one, but I wonder how these short little devices can do such an accurate job?
Anyway, a little FYI and information from my recent shop time.