The Pits, or “How I wish I had finished 9 Micron yesterday!”
When we last left off I built the Focal length tester and nearly finished grinding the mirrors, having done 2 wets each at 9 micron.
As I left the shop last
night, I washed the 2 mirrors and set them on a towel on the workbench. I also washed the surface of the tool where
it sat in the grinding platform. (Perhaps this helped cause the problem)
When I arrived in the shop
the next evening, the tool was still sitting in a puddle of water, I didn’t
think much of it at the time. Also
during work that day a front moved thru and it was rainy and cold (cold, yea
uhuh, I think it may have gotten all the way down to 70f, Its Florida in
March. I’ve lived here all my life,
what can I say)
Anyway, I wet the tool,
sprinkle some 9 micron on, wet the mirror and begin grinding. When you first put the mirror on top of the
tool, the most striking thing, down at this micron level, is the mirror glides
over the tool like Ice on Ice. After 5
or 6 strokes you begin to hear it start to grind. So I do twenty strokes, step 1/8 the way around the bench, do
another 20 strokes, step another 1/8 turn do about 3 strokes and the mirror
locks itself to the tool!!!!!!
Oh SHIT, I think at the
time. I’ve heard of this problem,
although till this very moment I have never experienced it.
So I confidently grab the
tool and figure I’ll just pull it back the way it came and it’ll come right
off. WRONG!
That damn mirror wouldn’t
budge, So I walk around the bench and try pushing it back the way it came from
the other side. I put all my weight on
that sucker and it didn’t budge. Now
I’m starting to get desperate, I need to get that mirror off of there NOW,
before the grit starts to dry. So I
whack it with the palm of my hand, nothing.
I whack it again and damn near send it flying across the room!!!!
Whew, I got it off! However, I’m concerned as to why it stuck at
all. So I think maybe I’ll try the
other mirror to see what it does. (proves to be a rather dumb idea…)
I wash the tool, add fresh
grit, wet the second mirror, and start grinding. At almost EXACTLY the same stroke this mirror sticks as
well! No problem I think, I’ll just
walk over and whack it a couple time with the palm of my hand and it will come
right off, just like the last one! NOPE
There I am, With the second mirror
stuck to the tool, and a rather sore hand.
So what do I do? I grab a 2x4
and a hammer, I’ll just give it a
little tap. “whack” “Hmmm”
that didn’t work…. I’ll just hit
it a little harder. “WHACK” “Shit”
still stuck. “WHACK WHACK WHACK!” “Shit Shit Shit” Still STUCK!
I toss the firmly stuck tool
and mirror in the wash bucket and begrudgingly call it a night.
Back inside, behind my
Computer, rather disgruntled at my mirrors, I shoot of an email cry for help to
the ATM list. Boy did I get some good
answers (as always!).
So I race back out to the
garage and to my surprise and relief the stuck mirror/tool slide apart! Whew, but I have some really nasty scratches
and a couple of “bruise” fractures from beating on my glass with a hammer.
Looks like I’m heading back to 25 micron for a while L