Using the Conical Disk along with the Planer/ Jointer Knife Sharpener

[reubenjames]

It's notable that SS also gives homebrew instructions for making a jig with a 45 degree slot for the blades and using the flat sanding disc (not conical) with a rip fence offset to limit the disc to blade contact. I think 45 or near there is clearly what they are shooting for.

[JPG]

It's notable that SS also gives homebrew instructions for making a jig with a 45 degree slot for the blades and using the flat sanding disc (not conical) with a rip fence offset to limit the disc to blade contact. I think 45 or near there is clearly what they are shooting for.

FWIW, When I used to sharpen jointer blades with that block of wood, I used the quill feed rather than the offset fence etc.. Very light pressure so the difference in grit speed due to radius difference became unnoticable. Also allowed shifting position.

Honing is the bottom line however!!!!

[dusty]

The first thing I must do is offer an apology to John for all of my negative thoughts and comments regarding this subject. I was dead wrong and he was correct. I must also thank Buckeye; it was his comments that made me stop and think.

To bring the whole thing into focus (for me), I had to draw some pictures. I prepared a very accurate drawing (Sketchup) of the sharpening jig and of the planer/jointer blade. With these drawings I could clearly see that the bevel on a planer blade is set back off of vertical by 3°.

That realization that rang the bell. The conical disk is also at 3° off of vertical. This makes the face of the conical disk and the beveled face of the jointer blade parallel. Hmmm. Why did I not see this before I made a fool of myself. Simple. I was taking all my measurements from from a new (unsharpened) blade. A glance at a sharpened blade reveals that most of my blades have altered bevels because I have, for a very long time) been tilting the table to make it square with the face of the conical disk. In so doing, I have altered the bevel by approximately 3°.

[jsburger]

No apology needed Dusty. I think we all learned from this discussion and that is what counts.

[JPG]

No apology needed Dusty. I think we all learned from this discussion and that is what counts.

Ditto!

The 'light' was provided by a couple of folks actually measuring the SS jig. Thanks for that!

[reible]

Now if I were to get this jig and wanted to do my jointer knives at the recommended 38 degrees I would then have to adjust the table to what angle?

See photo below for how angle is measured.

IMG_1460scm.jpg (119.7 KiB) Viewed 2672 times

The assumption would be the knifes are flat, at least that is my best guess. So with that in mind tell me how to do the setup.

Ed

[JPG]

Now if I were to get this jig and wanted to do my jointer knives at the recommended 38 degrees I would then have to adjust the table to what angle?

See photo below for how angle is measured.

IMG_1460scm.jpg

The assumption would be the knifes are flat, at least that is my best guess. So with that in mind talk me how to do the setup.

Ed

Assuming all the previous conclusions are correct(0 tilt yields 45°), raise the left side of the table 7°.

[JPG]

Where did that 1 degree post go John?????

[dusty]

Now if I were to get this jig and wanted to do my jointer knives at the recommended 38 degrees I would then have to adjust the table to what angle?

See photo below for how angle is measured.



The assumption would be the knifes are flat, at least that is my best guess. So with that in mind talk me how to do the setup.

Ed

Assuming all the previous conclusions are correct(0 tilt yields 45°), raise the left side of the table 7°.

Does this take into consideration reible's statement that he assumes the knives are flat? If not, there needs to be a correction for the taper that is on the Shopsmith knives but not on reible's. That taper is 1.5°.

[jsburger]

Where did that 1 degree post go John?????

I deleted it. After your post I thought I needed to rethink my Non-Geometry. If 0* table is correct for 45* then 7* to the right seems correct but something just made me want to think about it some more. I have thought and I was overthinking it and you are correct. Maybe