Re: ATM Tile Questions...

["Bill T." <twentiethwave@hotmail.com>]

>How large of a gap should I place between the tiles on the tool?

If you are going to hog out a flat blank, as close as you can get them!
There will be plenty of wear, you may even have to replace tiles once.  The
greater the total surface area, the longer they last.  Best to buy tiles
pre-mounted on a matrix for this.

If you're starting with a pre-generated mirror, fairly large gaps are okay.
This will speed all the tiles coming into contact, since with lower surface
area the wear rate on individual tiles will be faster.  With sparse tile
coverage (assuming a pre-gen'd mirror), the grinding goes much faster
because the tiles wear in sooner.  A 50% coverage tool may only lose about
1/16" going from 220 grit to 9 micron.  If well made, such a lap will
achieve full tile contact in ~15 minutes at 220 grit.  I've had equally good
grinds with tools ranging from full surface coverage down to 50% coverage.

I'd go to a LOT of trouble to move the polishing inside, IIWY ;^)

Bill T.