Lets talk jointer alignment (long)

[Dennis McDonaugh]

I'm in the process of changing the blades in my Grizzly 8" jointer, I've never done this before, but I've changed blades in my planers several times. I have three options for changing the blades. First, I have the alignment tool that came with the jointer, second I bought a jointer pal, and third I can use one of several alternative ways to align the blades I've read on different woodworking forums. I've changed one blade and here are my thoughts:

First, I don't want to move the outfeed table. The infeed and outfeed tables are parallel and I don't want to chance messing that up. The alignment tool grizzly supplied won't fit in the space between the infeed and outfeed table unless I lower both a little, or one a lot. And then I've still got to adjust the outfeed table to the new height of the blades. I don't want to do that so lets move on to something else.

The planer pal I have works great on my Jet 15" planer so I bought the jointer pal. My first impression was favorable as I read the directions. This quickly turns to frustration when I try to use it. The springs in the cutter head are stronger than the magnets in the jointer pal so the blades push the jointer pal off the bed of the jointer. That's no good so what next?

The alternative methods. I've seen two used. The first involves a straight edge which you lay on the outfeed table and then adjust the blades so they just touch the straight edge. The other uses a piece of wood and some tape. You place masking tape parallel to the blades on the outfeed table and draw a reference line on the tape. Then you place the piece of wood across the infeed and outfeed table, the blades "grab" the wood and move it slightly as they travel. The blades are aligned when the wood moves the same amount on each side of the blade on all three blades.

The straight edge seems the easiest and quickest to use (I used it on the first blade) and I'm going to use it on the other two blades. I guess the test will be how well the jointer surfaces and edge joints a board.

What are your thoughts on blade alignment and what methods do you use?

[Ron Meadows]

I was never satisfied with any of the methods that you discuss. No matter what I did I could never get the knives parallel to the tables and at the same height. I made myself a jig based on one end of the factory supplied knife setting thingy that was provided with my DJ-20. Everyone that owns a jointer has one of these things so here's what I did.
1. Take the supplied jig apart and lay one end of it flat on a sheet of paper
2. Trace the oultine of the piece and glue the pattern to a piece of 8/4 maple or other hardwood
3. carefully cut out new jig on bandsaw
4. stand new jig such that the arced portion is setting downward on a flat surface and find the center of the portion that is facing upward by marking the diagonals of the resulting rectangle.
5. drill a hole that matches the diameter of any dial indicator that you have laying around the shop ( I cut a relief cut in this portion of the jig so that I could get a snug fit on the dial indicator, but still be able to remove it for other uses)

You now have a jig that you can place directly over the knives that will reference the knife height directly to the cutterhead. Simply zero out the dial indicator at the desired knife height (on my DJ-20 it is 0.100" above the plane of the cutterhead) and slide away. With this jig I can repeatedly get my knives to within 0.001" of each other and exactly parallel to the tables.

I have some pics of the jig at home, but none here at work. If anyone's interested just let me know and I'll post them.

My $0.10 on the subject,

Ron

P.S. This jig will also work on 15" planers. I use it for both and it only cost me about $12 including a cheap dial indicator

[Jordan Lane]

since i own a DJ20 i would be very interested in seeing that jig

[Kevin Post]

Originally posted by Dennis McDonaugh
The springs in the cutter head are stronger than the magnets in the jointer pal so the blades push the jointer pal off the bed of the jointer. That's no good so what next?

I use the straight-edge method for setting the knives in my jointer.

I've never used one of those fancy jointer pal jigs nor am I familiar with your jointer but I'm thinking, 'Why not simply remove the springs?' You could use the magnet to help you remove them instead of having the springs boing 'em out of the cutterhead.

[Kirk (KC) Constable]

Dennis...I use the alignment thingy supplied by Grizzly with great success. I lower the infeed table all the way, then change the blades. In theory, if you use the alignment thingy each time, you should never have to adjust the outfeed table because the blades will be indexed to the cutter head, which never moves. The only time we've ever had to fiddle with the outfeed table is after somebody MOVES IT :mad: trying to make an adjustment based on a poorly executed cut. It takes me maybe 15 minutes to change the blades on the 1018.

Again...you don't need to move the outfeed table, and you shouldn't have to adjust it afterward. I think you'll be pleasantly surprised at how well the gauge works. If you're changing factory blades and DO end up having to adjust the table afterward, you shouldn't have to next time if you keep using the alignment tool. I think we all tend to make changing blades harder than it needs to be...I know I certainly did at first.

KC

[David Eisan]

Read this article I wrote,

http://www.owwm.com/FAQ/JointerTune.asp

David.

[Dennis McDonaugh]

Thanks for the input guys. I aligned the other two blades using a straight edge and the outfeed table and it the jointer works fine. KC, I didn't consider the that the alignment tool would provide a consistent reference so the outfeed table wouldn't need alignment. I'll give it a try next time. Thanks.