Jointer blade alignment tolerance

[uber_goober]

On my DJ-20, the blades were about .005 above the outfeed table. I'm tuning up all my tools so decided to do something about it. I got the jointer pal magnetic tool and to my surprise using that it ended up worse, at .007-.010 and uneven. I think its because of tightening the nuts inevitably moves the blade some.

So I decided to do it manually, and painstakingly set the blades purposefully a little low (this takes forever since a minute turn on the adjustment screw will throw it off). Then after tightening the blade the final alignment was about .004 above the outfeed table.

Is this close enough? I spent about a day on it and have bandaids on all my fingers :-) so my thought is this is good enough. I could try to move the outfeed table up .004 but my fear is that its likely to end up worse and I'll just keep fighting to get those last thousandths.

Will having the blade .004 above the outfeed table have a measurable affect?

I'm jointing some long 10' boards and before this did have a problem with both ends of the board being narrower than the middle. I'm checking both the jointer and tablesaw to try to get rid of this. Thanks for this and the other great advice I've gotten on here.

Eric

[George]

If you don't have a snipe - visually or audibly, at the trailing end of the board, you've got it right. If not, touch the table up until the snipe/sound goes away.

[Slowhand]

Dayem, here is my tolerance:

I use a piece of 6" x 3/4 x 3/4 scrap. I mark two lines on the scrap a 1/4" apart. I set the knives so they move my piece of 1/4" on both ends of the knives. And yes, make sure when you tighten, that the knives are still set where you thought they were. Sometimes they move. When all the knives are moving the scrap 1/4", life is complete.

Been succesfully jointing for years using this method. As they say, it aint rocket science. SH

[Roger Shoaf]

I don't think so.

I spent about a day on it and have bandaids on

Yes it will.

How did you measure the .004? If you have a dial indicator with a magnetic base you should be able to park the cutter head and dial the knife into the proper position. It is not clear from looking at the manual, but here is something to consider. Let's say the adjusting screw has 32 threads per inch. Turning it one complete revolution will move the blade 1/32 or .03125. 1/2 a turn would be a touch over .015 and 1/6 of a turn would be slightly more than .005.

If you can deturmine the pitch of the thread and give yourself a point of reference like in the above example, this should cut down on the frustrating over shoot under shoot that you have been experiencing.

You might be able to stick short end of the allen wrench in the screw, and place a protractor under the long end and be able to see how many degrees you are turning the wrench. In this case let's assume the screw has 24 threads per inch. That would be .0412/3 inches per turn of the screw. So

1/4 of a turn (90degrees ) would be just over .010 so 9 degrees per .001.

I hope this helps.

[DarylRos]

I've been told .002" However, a better test is to take a flat stick, maybe 1" square, 12" long, and mark two lines in tthe middle, 1/8" apart (be accurate).

Place the right hand line on the outfeed table, and then manually turn the cutter head. The stick should only move to the second line. You have to check at both ends, plus once at every jack screw.

[nospam_coloradotrout]

The 2 ideas about moving a stick seem to be winners.

1/8" is probably ideal, but 1/4" might be good 'nuf

next time i'm gonna try it

i've been fooling around w/ a dial indicator, but there's no good way to keep a solid reference pt

[George]

Screw around all you like, but it's results that count. Therefore, if the piece does not butt on the outfeed table -table too high- or snipe on the trailing edge - table too low - it's good. Save the stick for setting the knives at the same height.

[max]

I use a piece of aluminum but sometimes use my steel rule. I place a straight piece on the outfeed table and hold it down. I move the cutter head back wards until I feel the slightest drag on the metal bar. You can get really good and feel the slightest drag. I do both ends of the knife this way. You can get really fast with this method. Your sensitivity will be different but I can get it to 1 thou so so and usually on the first try. max