(ATM) Ferguson`s mirror 1

[Mike Abercrombie <abercrom@southwind.net> (by way of Mel Bartels <mbartels@efn.org>)]

KK> nearly everything but the administrative posts.  I found Allan
KK> Killian's

Kevin,

I'm not familiar with Allan Killian, but it sounds like you are off to 
a good start!

KK> I'm still trying to come up with a good grinding stand..Steel
KK> drums just don't seem to be as common as when I was a kid.  Ideas
KK> for alternatives, or suggestions as to where to find a drum, would
KK> be most welcome.

I used a barrel obtained from a grocery store...honey came in it. 
However, a more common place would be a surplus store. The barrels 
usually run $5 to $10. I didn't want to leave a barrel in my house no 
matter how brightly I colored it <g>. So, I built a stand from cheap 
pine lumber. I put a "shelf" about 6" from the bottom and with the 
top removed, I can drop a couple of 100 lb bags of concrete (still in 
the bag <g>) in the table for ballast. Works great and looks better 
than the barrel though it really doesn't work any better.

KK> I was quite anxious to see if my ceramic tool would work, so I put
KK> some wet newspaper on top of my washing machine (ahhh...the joys
KK> of bachelorhood!) Threw on some #60 (came with kit..books say
KK> start at 80??) and went at it.

It sounds like you have a raised tile tool (tiles glued to the ceramic 
base with a 1/4" gap forming channels). This is GREAT! Just fill the 
channels up with grit and the suction you described will pull fresh 
grit up onto the grinding area as the old is pounded into slurry. If 
it dries before the grit is used up and you still have strength left, 
just squirt a bit of water on the tool to liven it back up.

The same applies to the smaller grit though you don't "have" to fill 
the channels up.

KK> presume I should pretty much double everything (pressure, time,
KK> amount of grit, etc.) for my 8" due to ratio of surface area, and
KK> volume of glass to be removed?? If this is wrong, somebody please
KK> clear this up for me. (I think

This really isn't necessary. Especially in the early stages, more 
pressure just means that the grit will break down faster but you might 
get the hogging out done sooner. Check your sagitta (depth of curve) 
with a straight edge and an automotive "feeler guage". This gauge is 
what we use to check the gap on spark plugs and points in the 
ignition. Use the blade type feelers. Or, if you have a really good 
set of precision drill bits, you can use them.

KK> playing around with sketches, and doing a lot of reading, I have
KK> toned down my aspirations to f/6.0, which may still be a bit
KK> ambitious for a first

I think that Berry recommends starting with either a 6" or an 8". I 
recall the 8" being an f/6. Actually, this is not a bad choice since 
this deeper curve (deeper than an f/8) will make the zonal shadows a 
bit easier to interpret.

My first mirror was an 8" f/6 and I mounted it in an octagonal tube. 
I think the minimum diameter on my tube was 10". I never had problems 
with heat that a muffin fan on the rear didn't take care of.

KK> tube:        Plywood, octagonal, 11" minimum interior dimension

Mike (good luck)
 * RM 1.3  * "Ground Beef" -- A Cow With No Legs!