# Collins Microflat Company



## ferlum (Oct 21, 2016)

Picked this up a while back with some other stuff. Didn't have an immediate use for it so I covered it up and tucked it out of the way. Recently got it out, cleaned it up and got curious about the manufacturer, but googling didn't turn up much. I'm guessing they're no longer around.

Anyone know anything about them? Seems like a nice USA made plate but I can't find any info about it.


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## Bob Korves (Oct 21, 2016)

I have a Collins plate like yours.  Mine is 18x24", with two ledges like yours.  I bought it for $50 and got it calibrated and certified as part of a group deal we put together.  Standridge Granite out of Montebello, Ca. stopped by and did five plates for a group of us on one of their road trips.  It is pretty expensive to do one plate that way, because of a mileage charge and a minimum invoice amount, but with five plates the mileage charge was spread pretty thin and we were well over the minimum invoice number.  It was fun to have the group and their plates at my shop and get to watch the techs calibrate them.  Mine came from a rack outside of a small machine shop, so I knew it was worn and needed work.  Turns out it had a .003" "bowl" in the middle of it.  They got it to within .000030" (30 millionths) in well less than half an hour.  Very professional and hard working staff, happy to answer questions and kept us informed as they proceeded.  It is great to have a rock that I KNOW is flat, looked in the autocollimator and watched the repeat-o-meter slide around the plate with the 10 millionths graduated dial barely moving.  She still looks like an old plate, and she is, but I can trust this one...


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## Bob Korves (Oct 21, 2016)

Yes, Collins has been out of business for decades.  The rock is of course millions of years old, so it doesn't care.  It is just a label, what is really important is how accurate it is right now.  You can't trust it until you find out from a pro and get it calibrated as needed.


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## ferlum (Oct 21, 2016)

Thanks for the input Bob. All good points. I'm gonna look into calibration. Maybe I'll get lucky and find someone that can do it locally.


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## Ulma Doctor (Oct 21, 2016)

this is by no means testing  the accuracy, but rather a quick and dirty look,
if you have a straightedge, you can lay it on edge against the surface of the surface plate and light it from the back.
any low points of the surface plate will show up as a sliver of light.
if you can put a .001" feeler gauge in the sliver of light, that would indicate some wear.
check in many places across the surface, then at 90* to those checks- and you'll have an idea of the low spots- if any.
this does not take the place of calibration, but it will give a rough idea of wear.


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## ferlum (Oct 21, 2016)

Ulma Doctor said:


> this is by no means testing  the accuracy, but rather a quick and dirty look,
> if you have a straightedge, you can lay it on edge against the surface of the surface plate and light it from the back.
> any low points of the surface plate will show up as a sliver of light.
> if you can put a .001" feeler gauge in the sliver of light, that would indicate some wear.
> ...



I'll give this a try. The longest "straight" edge I have a is a 6" solid square...not sure how well that will work, but I suppose it would detect any really bad spots.

The local cal house we use at work can check/certify/resurface to any grade so I'll probably give them a call. They're pretty reasonably priced for most calibrations so I'm thinking an inspection alone wouldn't cost too much, and I'd have the peace of mind of knowing what I'm working with.


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## ferlum (Oct 21, 2016)

Turns out I can get it surfaced & certified to grade A by Washington Calibrations in Tempe for 64 bucks, just an FYI for anyone in the Phoenix area.


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## Holescreek (Oct 23, 2016)

If you're not in business inspecting or supplying inspection reports to third party suppliers (i.e. you're just a home shop guy) why bother throwing any money at all at a certification?


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## Ulma Doctor (Oct 23, 2016)

Holescreek said:


> If you're not in business inspecting or supplying inspection reports to third party suppliers (i.e. you're just a home shop guy) why bother throwing any money at all at a certification?



for accuracy's sake if nothing else!
i don't think anybody wants to set out to do poor work.
i think not knowing the accuracy is the worst part.
you may as well use the concrete floor slab in the garage if the plate is unknown


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## Holescreek (Oct 23, 2016)

The point of my question is not to poo poo the accuracy point, it's more to point out "the other side of the coin" to newbies that may read this thread and freeze up because they don't have a "certified" surface plate.  
You have guys using plate glass, marble tile squares, cheap import plates with bogus certs... and the *average* home shop hobbiest isn't surface grinding parts to print. It's going to get pretty expensive for you since now that your plate is "certified" you need to send your gauge blocks, indicators and measuring instruments out for their turn in the calibration lab too.  It's a circle of life that eats money and gets expensive if you aren't making any as a hobbiest.
But hey, if a sticker from some calibration place gives you bragging rights with your buddy's, OK.


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## ferlum (Oct 23, 2016)

Totally agree with the above points about hobby use. If that were the case I would just use the plate as-is and not worry about it.

But I have a small business designing and building tools/fixtures for a few clients. The cal and cert are still not an absolute requirement, but since I got the surface plate used, I'd like to know what I'm working with. After the initial calibration I'll probably never need to have it done again.


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## Ulma Doctor (Oct 23, 2016)

and there will be no question of it's accuracy, it will have nothing to do with bragging


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