Re: [ATM] hogging with diamonds

["Bob May" <rmay@nethere.com>]

The problems with diamonds are just like with any other method of
grinding the hole in the glass.  They will chip the edge if you
don't chamfer it before you get started as they do put the
pressure on the edge which can spall off a chip.
The diamonds are nice in that you don't need to go work with
repeated wets of grit which quickly wear down as they grind.
Properly used diamonds will last for a good amount of time.
Re,member that when you get the stress level up past a certain
point, diamonds will break off of the surrounding matrix of
nickel that they are mechanically held in with.  Just like any
diamond ring, put enough pressure on the stone and the stone will
come out of the ring.  Diamond tooling is intended to be used at
a fairly low pressure with a fairly high speed of cut action for
best life.  As with the original intent of the disks in tile
cutters, you are told to not feed the tiles too fast or the
cutter will quickly wear away.
I'm also sending this to the ATM list as it is a veery good
question about the use of diamond tooling in making mirrors.
I'll also note that all of the pregenerated blanks are usually
done with diamond tooling on huyge machines (huge to keep the
tool from chattering as well as to handle the large pieces of
work that need to be done on those machines) and that tooling is
lasting for a good long time or they'd not be using them.
Bob May

rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net

----- Original Message -----
From: horace r davis <hrd9@juno.com>
To: <rmay@nethere.com>
Sent: Sunday, March 16, 2008 1:22 PM
Subject: hogging with diamonds


> do you half to have a turn table to hog with diamonds wheel. or
would it
> chip the edge of the mirror if you do it by hand.
>

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