Changing jointer knives.

[Jim Davenport]

The knives on my jet jointer finally got too dull. I just got a new set from Global tooling.
Today I had some time to change them out. The Jet has springs to support the knives. I've figured out an easy method to change them. I have a line scribed on the fence indicating top dead center of the rotor. I removed the guard, then I removed the old blades, cleaned everything up with mineral spirits. I have a pair of "V-blocks", I use on the mill. with a little bit of weight, these keep the new knives level with the out feed table. I reinstall the knife, rotate it until it's lined up with the scribed line on the fence. I clamp the belt, and sheave to keep anything from moving. I use the weighted V-blocks to push down on the knife, level to the outfeed table. Carefully tighten the gibb locking bolts, unlcamp the belt. Carefully rotate the rotor and check clearance. Repeat for the other two knives. make test cuts, and adjust the outfeed table if necessary.
I'm sure someone has a better method, but this works pretty good for me.
"BE SURE TO UNPLUG THE JOINTER PRIOR TO WORKING ON IT!!!"
Now I have to figure out the jointer blade jig for the new Tormek and sharpen the old blades

[Allen Bookout]

Good instructions Jim. If you have not used your Tormek yet you are going to love it. Allen

P.S. Well---forget that. I see, by pulling up your other post, that you have already gone deep into the Tormek world.

[Jim Becker]

Interesting that your Jet has springs...the one I owned (Jet 6" closed stand) used jack-screws. But I see yours is blue, which would indicate an older machine. Jigging up as you have is the way to go with springs!

[Bill Webber]

I do it in a similar manner, using a 1-inch thick piece of glass instead of the V blocks. One difference, I use a piece of wood to push the blades lower into the cutter head and then snug them there with the two outboard screws. I then position the glass and the cutterhead and slowly release the cutter head screws allowing the cutter to rise gently. I fullly release the screws before beginning the tighten-up sequence. Pushing the knives down into the cutterhead with steel (or glass) seems a little unsettling.

Just my 2c...

[Byron Trantham]

Interesting that your Jet has springs...the one I owned (Jet 6" closed stand) used jack-screws. But I see yours is blue, which would indicate an older machine. Jigging up as you have is the way to go with springs!

I have the older Jet (Blue) and it has jack screws).

[Jim Becker]

I have the older Jet (Blue) and it has jack screws).

Interesting...

[lou sansone]

nice idea and good instructions
thanks
lou

[Jim Davenport]

This one is a old blue "JJ6CS". If I remember correctly, I bought it around 1993.

[Jim Davenport]

I do it in a similar manner, using a 1-inch thick piece of glass instead of the V blocks. One difference, I use a piece of wood to push the blades lower into the cutter head and then snug them there with the two outboard screws. I then position the glass and the cutterhead and slowly release the cutter head screws allowing the cutter to rise gently. I fullly release the screws before beginning the tighten-up sequence. Pushing the knives down into the cutterhead with steel (or glass) seems a little unsettling.

Just my 2c...
The first time I changed knives years ago, I polished the gibbs, and deburred the area where the knives sit. There's really no pressure on the knives, I've done this many times. I haven't seen any dulling of the knives.