[ATM] ATM: $1 wager to anyone on this list.

["David Harbour" <scarab2@cox.net>]

Waxed channels in faceted (channeled) grinding tool.

I will wager a dollar to anyone of you who uses my waxing regimen and 
methodology for the face of his or her channeled grinding tool, that he or 
she will never again fail to use it for grinding. There are slightly more 
advantages using it with my own special portland cement/ Winburne Hex tile 
tool which is the kind of tool I make for pre-curve generated blanks:

http://www.atmsite.org/contrib/Harbour/Tool.html


for moulding a new tool to an existing curve generated blank, but the 
primary and most important aids that it confers for grinding will convince 
you to use it for a tool that you built (epoxied together) on a glass or 
ceramic substrate also.

After the tool is constructed (flat, epoxied, or moulded to curve of mirror) 
the next step is to melt a bunch of wax and pour it all over the face of the 
tool; then:

After the wax has cooled, you can ruin a large, cheap carving knife to 
remove (scrape) the thick excess on the face of the mirror. You cannot get 
it all; the rest will come off quickly when you start roughing.

Then, use a small screwdriver to excavate only a little off the top of the 
wax in between channels. Yes, it will eat your little screw driver's blade 
as surely as it ruined the carving knife's blade. Cost of doing business 
this way, the perfect way.

Next, apply your coarse carbo slurry to the face of the tool, and put the 
mirror on it, and give the mirror a little swirling motion first, before 
regular stroking, to more evenly distribute the abrasive.

Then, grind off the excess of wax. Then, grind.

Then, when the tiles are all cutting, wet the back of the mirror to observe 
the action of the grinding through the back of the glass. Apply your carbo 
not already as a slurry, but sprinkle it on dry, in a big spiralling motion 
so as to approximately evenly distribute it, and then sprinkle on some 
water. When the grinding is progressing with perfect action, when the tiles 
are all cutting evenly, you will see what appears to be little amoebas on 
each tile, all surging back and forth as if they were drilling like soldiers 
on a parade field, in unison, and they will appear to stop at the edge of 
each tile they are on. Look closely, though, and you will see that in fact, 
the 60 grit is migrating back and forth evenly across the channels in a very 
thin layer of water. As soon as the little pockets of slurry on each tile 
seem to be migrating en masse, or if even a few seem to be stepping out of 
position as they are drilling with their fellow amoeba soldiers, across the 
channels, you need to stop, clean up, use your little worn down screwdriver 
to again bring the level of the wax down to slightly  below the grade of the 
tiles. Resume grinding. Do this all throughout the grind, including the 
finer grits. Use the tool as a substrate for the pitch lap later.

If any of you fail to find this advantageous, over whatever you have been 
doing, I will send you a dollar. You should face your tool with one inch 
diameter hex tiles, preferably with cushion edge. Hexes are more efficient 
than the generally and more widely available square tiles. They are 
available right here (with the helpful cushion edge) within about a 120 
second drive from my house. I will be glad to get any one of you some and 
ship them to you. Hexes are best. Channels should be 3/32" wide; they will 
be approximately .20 or .23" thick, unless you build this kind of tool, 
where in the depth of the channels will be slightly less:

http://www.atmsite.org/contrib/Harbour/Tool.html

Earn a dollar, if anyone of you needs a dollar. Try the wax protocal, and 
find out that you will never fail to use it again. If you do, ask for a 
dollar from me.

All grinding tools, even if you have a monolithic piece of glass that came 
with your mirror kit for the tool, should be faced with cushion edged, 
unglazed hex tiles. Now you know someone who will get them for you and ship 
them to you. But, you will have to promise to wax your tool!

Dave
 


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