[AlArchie]

Sorryy Ash, I misuderstod or misread your figures ie. (1/2000) one grain per .0002 or 2000 grains per inch. I think you meant 2/1000, 2 grains per .001 or .0005 (five ten thousandths inch grain size.) Now I concede!

Al

[Capt. Bandaid]

There is one thing that has not been mentioned and that is the loss of ductility at lower temperatures. Different steels exhibit this loss to differing degrees. Most do not transition from ductile to brittle until well below zero F. However, I have seen many occasions where a measurable loss has occurred at just below freezing (32F). This only represents a potential for chipping your tools where you might not have done so at room temperature. I suggest warming your tools up a bit before using them if there is frost on them. Do not put them in your mouth to do this

[AlArchie]

Boy, did I get my come-uppance! Wish I had taken a few more minutes to think my post through. I'm not used to thinking micron size stuff in terms of fractions (1/2000), but either in microns or decimals. After re reading the whole series of posts it finally dawned on me that Ash was absolutely right in the 1/2000 inch figure. 1/2000 really is 5 ten thousandths (.0005) or half of one thousandth.

REALLY SORRY, ASH. Brain fart on my part.

Al