Jointer knife set up jig
Posted: Thu Dec 10, 2009 8:40 am
I built this jointer knife set up jig a few days ago to assist me in properly setting my jointer knives. I didn't build it to to improve my accuracy in setting the knives but more because my ears don't hear as well as they used to.
For over 20 years I've set the knives the conventional way with a straight edge hanging over the outfeed table. I set the knives until they just "tic" the straight edge and make the slightest scraping sound. The problem is that my shop is in the basement along with my house mechanical systems. I also have a dehumidifier running. When these things are running; I find that I can't hear the knife scraping the straight edge any more. This jig gives me the visual reference I now need.
The jig is constructed from a small piece of cherry from my scrap box. I already had the dial indicator. First I jointed the bottom edge (on a longer piece and then cut off what I needed). I then cut out the notch so the dial indicator would hang out over the cutter head. I drilled a 3/8" hole from the top to fit the shaft of my indicator and a hole from the side for my wing bolt. I cut a kerf through the hole where the indicator fits so that when I tighten the wing bolt it will snug up the indicator. I installed two small magnets in the bottom to hold it to the jointer outfeed table.
To use it, first zero it out on the outfeed table. Then, extend it over the cutter head so that the tip of the indicator is at the high point of the arc and adjust the knives to zero on the indicator. I actually adjust mine to about .001 higher than the outfeed table because when I measured my knives from setting them with a straight edge that's where they measured. Works very well and easy.
For over 20 years I've set the knives the conventional way with a straight edge hanging over the outfeed table. I set the knives until they just "tic" the straight edge and make the slightest scraping sound. The problem is that my shop is in the basement along with my house mechanical systems. I also have a dehumidifier running. When these things are running; I find that I can't hear the knife scraping the straight edge any more. This jig gives me the visual reference I now need.
The jig is constructed from a small piece of cherry from my scrap box. I already had the dial indicator. First I jointed the bottom edge (on a longer piece and then cut off what I needed). I then cut out the notch so the dial indicator would hang out over the cutter head. I drilled a 3/8" hole from the top to fit the shaft of my indicator and a hole from the side for my wing bolt. I cut a kerf through the hole where the indicator fits so that when I tighten the wing bolt it will snug up the indicator. I installed two small magnets in the bottom to hold it to the jointer outfeed table.
To use it, first zero it out on the outfeed table. Then, extend it over the cutter head so that the tip of the indicator is at the high point of the arc and adjust the knives to zero on the indicator. I actually adjust mine to about .001 higher than the outfeed table because when I measured my knives from setting them with a straight edge that's where they measured. Works very well and easy.