Sharpening an End Mill on a Cutter Grinder

[Don52]

I sharpened my first end mill on my Cutter Grinder.

1. Dull end mill


2. Secondary angle position


3. Secondary angle close up


4. Primary angle position


5. Primary angle close up

[Don52]

6. Sharpened end mill


7. Cut with sharpened end mill


I was a little unhappy with the blue tint on the end mill, so I decided in the future I would take lighter cuts to minimize the heat in the tool. I also decided to use mist coolant on all of the grind passes as opposed to the last one.

If you want to use the thumb adjustor as a stop, you need to reverse the screw.

8. Original configuration


Otherwise, the end of the thumb adjustor sits on rubber, which isn’t solid enough.

9. Rubber on stop


The other problem is that the screw on the thumb adjuster was a 10 mm metric fine thread that was still 1.25 mm/rev. (Which is still fairly course for fine adjustments.)
I decided to replace the thumb screw with a micrometer head. It should be easy to take a .005” final cut with the micrometer head.

10. Micrometer head

[Don52]

11. SolidWorks design


12. Adapter


13. Micrometer installed


The attachment for end mill sharpening had 24 pin holes for indexing the end mill to the six required positions.

14. Detent positions


I have an air bearing attachment that looks like the following, which is designed to sharpen the OD of the end mill.

15. Air bearing attachment

[Don52]

The attachment guides on the helical flutes. I do have an endmill that requires sharpening on the OD, but I haven’t gotten around to trying out this attachment yet.

16. Guiding on helical flutes


-Don

[Weld dr]

I used to sharpen them buggers when i was younger in my 20s it was a great job and paid pretty good at the time. It was a fun job. Sadly i moved into the welding repair world..
...

[Don52]

I used to sharpen them buggers when i was younger in my 20s it was a great job and paid pretty good at the time. It was a fun job. Sadly i moved into the welding repair world..
...

The other problem is that the cost of sharpening an end mill is almost the cost of an inexpensive Chinese end mill.
45 years ago I was in charge of the model shop with two machinists for the company that I worked for. We used to put dull endmills in a bucket and sent them out for sharpening every two weeks.

The other advantage of this cutter grinder is that it is a very flexible conventional grinder, with a ton of attachments. I can also do conventional grinding in addition to sharpening cutters. One problem with this type of machine is that the gradations on the vertical axis is in .001". Conventional surface grinders are in .0001". Another problem is that the travel is fairly limited. My friend Dan has a surface grinder and he lives only a few miles away. I have used his grinder in a pinch, when I required the additional accuracy or increased travel.

-Don

[ryanjones2150]

I’ll have a box of end mills to send you. You can practice sharpening until your heart is content!

How long does it take to sharpen one?

[Don52]

I’ll have a box of end mills to send you. You can practice sharpening until your heart is content!

How long does it take to sharpen one?

This was the first end Mill that I sharpened. It took me about one hour. I bet that I could do the second one in less than 20 minutes.

-Don