Sharpening involute cutter

[ShedBoy]

After cutting into some mystery material which work hardened I ended up with a rounded off involute cutter. I need to take the tooth back about 1.5 to 2mm. Anyone got a pic off how to do this? I was thinking a mounted 3mm grinding disk, table of some description with a locating stub in the middle and a pin to pick up the teeth to hold it still. I have bought a new one but will need to sharpen these one day. I am sure the magic 12° will come into it somewhere.
Any thoughts
Brock

 

[magdriver]

I am also trying to find what the relief angle is on the tooth for sharpening gear cutters looking at end mills and slot drills the angles are 6 deg primery and 12 deg secondry so on that assumption I was going to go for the 6 deg angle for sherpening the faceof the tooth

I will be grinding them on the Worden tool and cutter grinder that is supplied as a kit from hemingway in the U/K for just under £400 have sharpened end mills, slot drills and slitting saws with no problem at all plus special lathe tools.

I have made a holder for the gear cutters but need to know what the relief angle is before they touch the diamond wheel.

Will post some photos of the holder and how they turn out sucessful or not.

Baz

 

[MuellerNick]

For re-grinding gear cutters (and hobs), an indexing stop on the next/previous tooth won't work that well. You need an indexing work head.
Also the rake (?) is 0°, the face of each tooth meets with the center line. Otherwise, you will have distortions of the profile.


Nick

 

[chipenter]

You need to grind the leading edge in some form of indexing , to take off the same from each tooth , otherwise the teeth will be uneven .

 

[pgp001]

I grind the backs of the teeth first, using a detent against the cutting face of the tooth, this ensures all teeth are the same thickness.
This allows the teeth to be indexed using the detent on the back of the tooth and out of the way of the grinding wheel whilst doing the actual sharpening.

 

[Fluffy]

G'Day Brock & Baz,
The method that I use for grinding involute gear cutters is as follows.
- Use a dressed saucer grinding wheel, align the grinding face of the wheel with the grinder tailstock centre (see Image). Lock the table cross feed. Then as indicated by pgp001, set up the cutter to lightly grind the backs of the teeth (approx 10 mm) to give an accurate surface for the toothrest to engage. This only needs to be done prior to the first sharpening.

- Mount the cutter on a mandrel & set between centres. Bring the cutter & wheel into very light contact. Mark the back of the first tooth to be ground with a permanent marker for reference.

-Set the toothrest so that the adjustment of the toothrest will slightly turn the rake face of the cutter toward the wheel to set the depth of the grinding cut. Lock the toothrest position.

- Traverse the table to grind the tooth.

-Repeat for each tooth.

- For each further cut, start at a different tooth to accommodate any wheel wear.

- When finished the tooth should have zero degrees radial rake to produce the correct tooth profile.

The diagrams are from an old text book of mine.

Hope this helps,
Don.

 

[purpleknif]

I take them to the sharpening shop down the street. Costs about $7.