another sharpening question

True, it will become bigger with each touch up. You can keep going until the micro bevel becomes the entire bevel. However it will take you longer & longer as the micro bevel becomes bigger & bigger. It's up to you how much longer you will tolerate this before staring again,.

Art

Sure, I have a scraper that I think is carbide with a 90 deg. blunt end. I can shave cast iron with minimal effort. The business end holds a 1" x 1" x 1/8" piece of metal that is very shiny, almost like chrome, that can be taken out and turned if needed. Was given to me 20 years ago by a guy who worked at a giant manufacturing/machine company. Not really sure what it is but man can it cut metal.

The original micro bevel should be made with only 2 or 3 passes across the stone. When you find that you are making many more passes to sharpen the edge it's time to grind back at the original bevel plus 2 or 3 passes for the new micro bevel.

It's a scraper. :)

I think companies like Bridgeport still hand-scrape ways to get them to the proper degree of flatness, but I could be wrong there- at any rate, it's the old way of getting the ways and work surfaces flat for machine tools. Handy thing you've got there- I've never seen one made for the purpose, they're usually just bits of ground-down old files.

This looks like it might be the exact tool I have.