"stu" no where just yet wrote in message
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"Ed Huntress" wrote in message
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"Ed Huntress" wrote in message
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"stu" no where just yet wrote in message
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"Ed Huntress" wrote in message
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"Ed Huntress" wrote in message news:...
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On Sun, 14 Mar 2010 00:55:03 +1100, "stu" no where just yet
wrote:
wrote in message
news:cu3np5la85p48d0vchp58tos9do4fun5me@4 ax.com...
On Sat, 13 Mar 2010 20:55:17 +1100, "stu" no where just yet
wrote:
I've just posted a picture in http://www.metalworking.com/Dropbox
called
"stusplate"(is it the done thing to put a direct link here?)
As you can see from the reflection of newpaper, the surface has a
very
fine
finish like no surface plate I have ever seen. It comes in a felt
lined
lockable box. Does anyone have any idea what this sort of plate
is?
Could be an optical flat. Your jpg doesn't show the size.
Inspection grade optical flats are typically 5 or 6" dia and
polished flat to within a fraction of the wavelength of green
light.
Jim
So that would be pretty flat then lol
I have two, one is 170mm(7inches) x 35mm(1.5inches) thick. The
other is
220mm(9inches) x 35mm(1.5inches)they are labeled "precison plate"
I thought about optical flats but I thought they were made from
glass?(although I'm not even sure I've ever seen an optical flat)
Most optical flats are glass or quartz. I have a 6"dia x 1/2"
glass flat. Although your flats are opaque, bearing in mind the
polish, the thickness and the careful packaging, I still think
they are likely to be flat to optical precision standard
Jim.
Stu has a couple of toolmaker's flats. They're made with a surface
that allows a gage block to be wrung to the surface, so that clamps
aren't needed. It's frequently used in gage labs for qualifying and
certifying instruments. Standard sizes are 2" and 4", so Stu's are
something pretty special. I've seen them that big, though, in
Mitutoyo's qualification lab.
If you keep that surface scratch-free, there's no better way to set
up a stack of gage blocks to extreme, certifiable, transferable
accuracy.
--
Ed Huntress
BTW, I should mention that their original purpose, which is now about
30 or 40 years out of date, was to qualify custom gages that were
used in production manufacturing -- go/no-go snap gages and so on.
--
Ed Huntress
Thanks Ed (and others)
There are some light scratches in the small one, just behind the
person it the photo. I didn't do a very good job cleaning the block as
I wasn't sure what to use. I'm yet to clean the large one, I'll try to
get onto it this evening, but what to use? I'm guessing "kero and a
rag" aren't the done thing.
Kero and a rag isn't bad at all. Don't use anything the least bit
abrasive or corrosive to steel. No Windex. Then lightly oil it with a
rag and put it away. Wipe the oil off before using. If you're going to
try wringing gage blocks against them, clean with a solvent on the
working surface, really well, first. Paint thinner should do it.
I believe you are right about the "production manufacturing ", they
have a name plate from a wire company where I am guessing they were
used, but they have no other name on them.
I'm try and get some more info on here tonight.
thanks again
Stu
You're welcome, Stu. They're interesting tools and they don't take up
much room. With scratches, you probably won't get much for them, so
you'd might as well keep them.
Do you have a set of gage blocks?
--
Ed Huntress
I've uploaded a couple of pictures of the large plate after a quick
clean wipe of kero.
http://www.metalworking.com/Dropbox/stusplatelarge.jpg
http://www.metalworking.com/Dropbox/stusplatelargeb.jpg
as you can see the isnt as good as the small one. I would think that it
is still plenty good enough for me. It will be nice to have something
"flat" in the shed, even if it is a little over the top.
I dont have gauge blocks yet although I am keeping an eye out for some,
I cant really think of an excuse to buy a new set.
You may or may not have a need for them, depending upon the kind of work
you do. I don't think most hobbyists need a full set of gage blocks, but
I do find use for a few very good ones, to check my mikes, calipers, and
height gage.
But those plates you have are not something any of us would really need,
either. They're nice to have. You can get some use out of them, but it's
unlikely you'll be qualifying gages or making production gages. g
--
Ed Huntress
Very interesting info guys. I was thinking about spotting them with
bearing blue to see how close to each other they are. There wouldn't be a
problem with that would there?
Try it. If you can't get a good read, use jeweler's rouge. That's what's
used for checking iron surface plates that have been scraped; it may or may
not work better than blue on lapped surfaces.
It's difficult to spread an even coating of rouge. If you have some in a
stick, for use with a buffing wheel, take a rag, wet it with paint thinner,
and rub it good on the rouge. Then, while the rag is still wet, try wiping
an even but thin coating on one of the plates.
This is easier said than done, but it works well with finely-scraped
surfaces.
As far as needing gauge blocks goes. All of my work so far(very limited
and not in the same league accuracy wise) is what I call "comparison
measuring", so my mic's could be calibrated in westernwigets for all it
matters. As long as they are consistent.
That's the way it is with most hobby work. For lathe work, I just use spring
calipers most of the time.
--
Ed Huntress