"Richard Smith" wrote in message ...

"Jim Wilkins" writes:

"Bob La Londe" wrote in message ...

On 8/3/2020 2:57 PM, Jim Wilkins wrote:
"Bob La Londe" wrote in message ...

A while back I picked up an inexpensive (relatively speaking) 6x12
surface grinder. It does a pretty decent job for light cuts if the heat
doesn't start to build up.

I thought very light cuts was what you do with a surface grinder?
Machine on eg. mill within 10thou / 0.25mm, then very lightly grind to
get the surface-ground finish. Watch the machining marks having their
tops removed until they disappear.
I realise though now that I never needed an exact size - only that the
surfaces were truly smooth, flat and parallel... Makes a difference?

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That's what I was taught too, remove less than 0.001" per pass when using a
horizontal shaft surface grinder. Vertical shaft Blanchard grinders are for
the heavy production jobs.
https://www.metalsupermarkets.com/di...sion-grinding/

I've seen a wheel shatter when the operator tried to take too much. I was on
another grinder perpendicular to the path of the fragments, one of which
loudly dented the loading door.

However the seller of my small grinder told me he had nearly worn it out
pushing it to its limit. He asked $50 for the grinder and $50 for the mag
chuck. Apparently it tolerates a heavier cut because it is more adjustable
and thus more flexible than a standard grinder, though less precise. I was
able to resurface my ancient British anvil on it.

https://ozarktoolmanuals.com/machine...-parts-manual/

I found its swivel table for cutter grinding in a used machinery store that
didn't have the grinder or know what the table was for. I had to make the
missing base for it. The head and column rotate to angle a cup or dish wheel
so the far side clears the work and poppit heads. The Quorn appears to be a
smaller copy. The grinder earned its cost back quickly by salvaging cheap
dulled large pipe taps, brand name end mills and the cutter head of my
woodworking jointer. Grinding the carbon steel blades without burning
required cuts so light I could barely hear them and didn't see sparks.

Notice that there's no provision for coolant, unless one puts a baking pan
under the mag chuck and caulks around it. A drain can be fabricated from a
brass pipe fitting by turning one end into a thin tubular rivet and
expanding and soldering it into a depression hammered into the pan.