Re: [ATM] machine hogging

[buck childers <bchilders@everestkc.net>]

----- Original Message ----- 
From: "Woodchuck" <djv@bedford.net>
> > I didn't get any responses when I asked whether it was
> > normal for 3 hours of machine grinding/hogging with a
> > cast iron gear and #60 grit to produce at MOST a
> > 0.002" depression on a 16.5" plate glass mirror blank.
> > The gear weighs about 5 pounds, I guess.
>
> You are using the gear as a tool?  If so, is the proper
> curve generated already on the tool, i.e. by a lathe?

I assume he's using the gear as a subdiameter ring tool.  Hogging out
with a ring will work to make a smooth spherical shape.  The edge of the
tool does the work as it's the only part in contact.  Traditionally a
cast iron ring is used.  Something about 1/2 the diameter of the glass.
Old cast iron plumbing fittings work.  But check your local TV listings.
I think Mythbusters has a segment on cat food tins being used for the
purpose.  -Buck

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