advice need grinding Rockwell C 60 part

[TheBigLebowski]

The washers ready to go to heat treat. I made an extra large one as a practice piece. Ground with the same 46H wheel I used on my chuck. I will be getting the recommended Norton 5SG-46H for grinding the hardened washers.


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bll230, I tried to respond to your pm but your inbox is full, Response below.

Sorry for the delayed response, I hope you were able to grind those parts without too much trouble.

Plunge grinding is done with no crossfeed motion, only table and downfeed are used. Each time you pass the wheel over the part, you feed down slightly so wheel continues to grind away at the part. You do this until you've reached the depth you want. This will leave you with a slot the same width as the wheel that is near finished depth.
Next you would raise the wheel up to clear the part, feed over slightly less then the width of the wheel and repeat to cut away another slot, continue repeating that process until the entire surface is lowered.

It works great for roughing small parts where the wheel isn't in contact with the part for very long, though it would be ill advised to use on longer parts.

As for manual grinding (in my opinion) is capable of taking deeper cuts, its simply because you have more control and feedback on what the grinder is doing. You can almost instantly feel when a cut isn't quite right on a manual grinder and correct course.

On the flip side, it's not necessary to grind aggressively using an auto grinder with coolant, as you can simply walk away with it and let it do its thing.

 

[michiganbuck]

likely I already mentioned this, the chuck area far from your bump rail and close to the operator is often the most accurate part of a chuck and off to the right or left can be even closer. The fresh dress may be a little rougher finish than a wheel with a little grinding on it.

Gauging the part and even taking the last half thow can be done on a piece of abrasive paper.
Automotive wet paper is likely the best..and you can make it .000025 flat and size along with a mirror finish.

Still, you have to consider heat swell with using abrasive paper.

*Oh, and debugging between grinds can save the part from scrap.

 

[bll230]

Here are the parts back from heat treat. News in my life is I am moving, so this project is going to be paused for while. Some here may have given me thoughts on how to move the machines on my moving thread. I'll get back to this thread this summer.

Thanks to all. John

 

[rogertoolmaker]

60H and 100K is the smallest grit I would try. Using 150 and 220 grit may cause trouble with burning. Dress the wheel using a sharp diamond. The traverse speed used to dress the wheel can affect the finish.

Roger