Installing Jointer Blades

[dusty]

When installing jointer blades (new or resharpened), the blade height is to be adjusted based on the cutting edge being at top dead center (TDC).

Is TDC always at the point where the cutting edge is directly above the center of rotation, even with blades that have been resharpened a couple times.

I came up with this question when attempting to secure the cutter head in the proper position in preparation for blade height adjustment.

[wa2crk]

Dusty
Yes the cutter blades should be at the TDC spot of the rotation. It is difficult to to prevent the cutter head from rotating when adjusting the height. I found that the best way to adjust the blades is to follow the instructions in the jointer manual. Use a small piece of hardwood with lines spaced about 1/8 inch apart. The height adjusting screws should be adjusted in the counter clockwise direction only. If adjusted clockwise the blades may be pulled down when the wedges are tightened changing the adjustment. When the cutter head is rotated the hardwood block should move only one division. There is only the very slightest amount of material that is removed when the tables are set at zero.
This system is only valid if the the tables are co-planer and true to each other. Set the tables before making the height adjustments.
After I re-conditioned my son's jointer and had the blades set exactly as the MS stated I removed the masking tape from the tables and the hardwood adjusting block moved another two spaces, so a little goes a long way with these adjustments.
This is a "trial and terror" adjustment so be patient. Also number the cutters in the head so you don't adjust 4 cutters. It's easy to lose track.
Don't ask me how I know!!!
Bill V

[JPG]

'Cutting edge' TDC is always directly above the axis of rotation at a right angle to the coplaner table tops.

However, the rotational positioning of the head will vary with different blade 'heights'. That variation may be due to actual blade dimensions(old vs new) or the setting of the height screws.


I have to reinforce W2's comment re direction of adjustment of the height screws. Once you get too high, you need to back them off and start over! The screws only raise the blade. They cannot lower the blade. Sorta like backlash, but moves only in one direction.

P.S. Dusty I realize you already know that, but thee are not the only one who will read that.

So if considering a jig to position the cutter head, it needs to be adjustable.

[dusty]

I am tinkering with this because I have a lot of time on my hands while I wait for the doctors to all release me from my restrictions. Believe me, except for my wife's watchful eye, I would already be out there making saw dust. She won't even allow me to carry groceries into the house from the car.

Enough of feeling sorry.

I have changed blades in my several times and I really know how to do it. However4, there has to be a more convenient and less frustrating way to deal with the cutter head andf the blades while doing this remove/replace/readjust routine.

I am contemplating some sort of fixture that will lock the cutter head at the correct point in rotation. Something that will very easy to use and even more easy to install an remove. In years gone by, I have clamped a pair of vise grips to an extender applied to the cutter drive shaft. The weight of the vise grips retards any tendency for that shaft to rotate.

I enjoy doing these little tasks - I have about six of them in the works - but I would much rather enjoy the aroma of freshly made saw dust.

[wa2crk]

JPG
What happened to the "hat"?
With the block of wood method the blade only touches wood at the TDC of the rotation regardless of the width of the blade due to sharpening. All blades will be in the same reference to the tables even if the blades are not the same width. (due to sharpening) I have used the magnetic holders and have not been happy. I get very consistent results with the owner's manual method.
Bill V

[JPG]

JPG
What happened to the "hat"?
With the block of wood method the blade only touches wood at the TDC of the rotation regardless of the width of the blade due to sharpening. All blades will be in the same reference to the tables even if the blades are not the same width. (due to sharpening) I have used the magnetic holders and have not been happy. I get very consistent results with the owner's manual method.
Bill V

It dry rotted!

As the blade narrows due to repeated sharpening. TDC will change relative to the angular position of the cutter head. Yes it will remain directly above the axis, but the head will be rotated differently.

I am not satisfied with the SS M VII logo, but it will have to do for the time being. It is a scaled down version of -

mark vii logo 2 reduced.jpg (1 MiB) Viewed 14559 times

[benush26]

I am contemplating some sort of fixture that will lock the cutter head at the correct point in rotation. Something that will very easy to use and even more easy to install an remove. In years gone by, I have clamped a pair of vise grips to an extender applied to the cutter drive shaft. The weight of the vise grips retards any tendency for that shaft to rotate.

Hey Dusty,
I stumbled on and tried the very same idea some time back, but abandon it because I could not get the vise grips to keep from moving ever so slightly, finding their weight rotated the shaft after I clamped them. As much as I tried to eyeball where the plumb bob effect was and tried to match it, I just could not get it! Glad you were able to make it work!!

And yes, the first time I reinstalled resharpened blades I did the rookie mistake of lowering the set screw and could not figure out why the danged blade did not go down!! . Operator error is a tough thing to live down!

Be well,
Ben

[JPG]

Router chuck 1/2" end to the jointer, 5/8" end to a 5/8" shaft(mortise holddown) and a sanding disk attached to that. Rig a saddle block across the way tubes and attach a clamp that tightens(squeezes from both sides) against the disc.

Random brain waves.

[rpd]

JPG
What happened to the "hat"?
With the block of wood method the blade only touches wood at the TDC of the rotation regardless of the width of the blade due to sharpening. All blades will be in the same reference to the tables even if the blades are not the same width. (due to sharpening) I have used the magnetic holders and have not been happy. I get very consistent results with the owner's manual method.
Bill V

It dry rotted!

As the blade narrows due to repeated sharpening. TDC will change relative to the angular position of the cutter head. Yes it will remain directly above the axis, but the head will be rotated differently.

I am not satisfied with the SS M VII logo, but it will have to do for the time being. It is a scaled down version of -

The attachment mark vii logo 2 reduced.jpg is no longer available

Would this work.

mark vii logo 2 icon.jpg (5.3 KiB) Viewed 14546 times

[benush26]

Router chuck 1/2" end to the jointer, 5/8" end to a 5/8" shaft(mortise holddown) and a sanding disk attached to that. Rig a saddle block across the way tubes and attach a clamp that tightens(squeezes from both sides) against the disc.

Random brain waves.

Would those be Alpha, Beta or Theta?
Anyway, what about setting up the jointer as though you were going to use it, attach the sanding disc to the quill, bring the table next to the disc, set the jointer blade to TDC, press the table next to the disc to keep it from moving, lock the carriage and adjust the blade height? Or have the table close and carriage locked, but extend the quill until the disc holds against the table and lock it? Either way, the sanding disc helps align TDC and then it is kept motionless while the blade height is set.

Be well,
Ben