Surface Grinding

[Harold_V]

My machine is light, so depth of cut is limited. I do roughing at a bit less than half wheel thickness.

My opinion only, based on a grinder suited for industrial use.
Depth of cut is always limited, even on heavier machines. However, when you use the corner of the wheel, the load is no heavier than when you use a large portion of the wheel as you do. A two or three thou depth of cut with a moderate stepover shouldn't tax the machine any more than the cut you're taking now, and the resulting finish will most likely be improved. That, of course, is much easier said than done when your machine has no power feeds.

If your machine is single phase you are most likely not going to be able to eliminate the slight waviness I see in the grind. That's most likely due to the pulses of the motor. Note, also, that those waves can be the result of a loose wheel, or one that is dulled or loaded.

If you intend to continue grinding as you do, you most likely would be best served by dressing the wheel before taking any finish cuts. When you grind with the bulk of the wheel face the wheel experiences general degradation and may or may not provide an acceptable finish.

Many of the experienced toolmakers like a manual grinder, and often without coolant. I do not subscribe to that concept and have done a serious amount of tool grinding with the feed powered and coolant provided machines. The heat generated in grinding is often troublesome, both in holding size and flatness. Coolant provides a more constant temperature and, as a bonus, may play a minor role in keeping the wheel from loading.

Any guesses on how long before I'm setting up to grind the cylinders?

Not soon...

Well, depends on how you intend to do the grinding. I don't see centers, so that may relegate the job to a centerless. There are centerless attachments available for use with a surface grinder, but I have no experience with them. I have operated centerless grinders, however, and I do understand them and how they operate. They are rarely found in the common machine shop, but often in production grinding shops. They do not lend themselves well to small lots, due to the rather intensive setup procedure, but they put out work at an astonishing rate, with the ability to hold extremely tight tolerances and provide exceptional finishes.

Nice job on the sine bar!

H

[ctwo]

This is just roughed in. I have done a few parts since dressing. I mostly wanted to get rid of the surface rust/pickled look, and it was a couple thou to dust off the pitting. I was pleased at how it ground in as there were no heavy spots to note, nice and even.

I have noticed a fresh dress does improve the surface quite a bit. It's single phase so will just have to live with what I get. It's not direct drive and I have seen finishes as good as I'd expect. I really enjoy what I am getting.

Now, this seems a bit dangerous, and he says so at the end. Don is grinding a flat plate by rotating it for each pass with mag off. How does he know he's not rotating the part over grit? I've tried crossing my grinds and don't much like the result. Even lapping I'm going to want to lap out the original grain.