jointer knife setting jig

[bluedawg76]

this was my first time changing jointer knives. Rather than buy/use a jointer pal or one-way jig, I came across a thread or two mentioning an easy to build (i.e. cheap) variation on this theme using glass and some magnets. I'm sure others have seen this or similar.

I used some 3/32" thick glass from the HD cut at ~4 1/2" x 9". I glued 2 sets of 6 small neodymium magnets (double-stacked) from Harbor freight about 3/8" from one edge to hold the jointer knives in place and 2 sets of 4 (double stacked) to hold to the outfeed table. The key here is that the magnets are on top of the glass pulling the knives flush with the glass. Having the magnets about 3/8" from the edge of the glass allowed me to tighten the gib screws while holding the knife in place. After some initial tinkering (finding TDC and a spot ~0.002" below), it only took a few minutes to set each knife at 0.002" above the outfeed table (based on my dial indicator). What do others prefer for the height? I've heard dead on flush with the outfeed or 0.001-0.003" above is ok.

View image in gallery​

View image in gallery​

 

[Cato]

I have yet to change my jointer knives and been kind of dreading the day since I hear how difficult and time consuming it can be.

Your jig is so simple yet effective, I see light at the end of the tunnel.

Thanks for the post

 

[Tarhead]

Find a piece of tissue paper to lay on the outfeed table under the glass. This will give you an offset of a few thou.

 

[Bas]

Very nice solution. I built one using plywood and magnets, which worked, but I was always concerned about the force with which the knives would hit the magnets. Not much point in getting your knives perfectly aligned if the setting process dulls them. Using glass in between prevents that problem.

 

[Sully]

That's slicker'n cat snot. I like it. :thumbs_up

 

[CarvedTones]

Find a piece of tissue paper to lay on the outfeed table under the glass. This will give you an offset of a few thou.

How thick is painter's tape?

 

[Tim Sherwood]

Great info! Thank you. I wonder if there is a similar set up for planer knives?

 

[Tarhead]

How thick is painter's tape?

~.007" with the adhesive

 

[drw]

Thank you for posting a very nifty solution to a somewhat tedious task. In response to your question, with respect to blade installation, I would be perfectly satisfied calibrating the blade tops flush with the out-feed table; the key for me is getting them flush across the width of the out-feed table (which your technique should do nicely).

Donn

 

[junquecol]

Very nice solution. I built one using plywood and magnets, which worked, but I was always concerned about the force with which the knives would hit the magnets. Not much point in getting your knives perfectly aligned if the setting process dulls them. Using glass in between prevents that problem.

Glass is harder than the magnets. I use the jig from John White's book "Care and Repair of Shop Machines." Then I check with my dial indicator.