Re: [ATM] Another machining question, please

["Don Clement" <don_clement@charter.net>]

IMO, it is not a good idea to dunk a hot HSS bit in water coolant in between
grinding. Dunking  hot HSS in water in water does not change the hardness or
temper, but  can cause micro cracks in the surface.  I grind slow or let the
HSS bit remain hot (red hot is OK for HSS) or cool with a constant coolant
stream. I use the constant flow of cold air from a vortex cold air gun while
grinding.

Don Clement
Running Springs, California


> Other than take it slow when grinding, don't push too hard, try to keep
the
> two edges equal in angle and cutting area/width, and cool often, I usually
> grind for about 2-3 seconds dip in the coolant (water, or soluble oil work
> great) for about 5-10 seconds (really depends on the size the object is
and
> how critical maintaining the hardness/temper is) bigger items get a longer
> dunking....

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