# Optical Comparator or microscope?



## fretsman (Jul 26, 2013)

Hi all,

I was hoping some of you could guide me as to what I should purchase. I do a lot of CNC engraving and needless to say, it's tricky getting a good look at cutter tips to see condition, size, shape, etc. 

I don't have a LOT of room in my tiny garage shop, so I was curious to know your experience and thoughts about using an Optical Comparator or microscope? What do you all use? We have a nice Mitutoyo at work, and while it's very nice to use that, it can be a bit of pain at times as you can imagine. It'd be very handy to have something at home to use when needed.

Thanks for your time and thoughts-
Dave


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## Bill Gruby (Jul 26, 2013)

The microscope will allow you to see the shape as you grind but it cannot compare to anything. The Comparator does what its name implies. It allows you to see the tip against a known shape on a transparency. The do make comparators that are Bench Top. 2 cents worth.

 "Billy G"


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## Ray C (Jul 26, 2013)

We had an optcial comparator at prior job and it was pretty useful because you could get very good approximations of actual measurements.  There is a grid that is overlayed on the viewed screen and the graticules are of a known spacing.  You could magnify the image such that two chosen landmarks on the piece line-up to the graticule borders and from that, a simple calculation would tell you the distance between the landmarks.

Ray


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## fretsman (Jul 26, 2013)

Thank you both for your thoughts, they're much appreciated. 

Do they not make a microscope that has retical/graduated style lenses?

Thanks!
Dave


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## Bill Gruby (Jul 26, 2013)

Yes they do but off hand I don't know the manufacturer.

 "Billy G"

 Found this      http://www.microscope.com/stereo-microscopes/industrial-inspection/?gclid=CPO33fOyzbgCFQ2Z4AodCjsAyg


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## Ray C (Jul 26, 2013)

The one we have at work is purely electronic with the display showing-up on built-in display.  It's made by Dazor called a speckfinder.  If I had to take a guess, it's probably in the 10 grand range.  It's a very common unit used for crime/evidence analysis and I believe it has comparator ability but, I never use it for that.

That said, you could probably buy an inexpensive USB magnifyer, take pictures of known graticules then, once the images are loaded into the computer, do the overlay with software (possibly just a word processor or photo editing program).  Mabye there's already software that does this or comes with the USB cameras... -Just guessing.

BTW: Decent USB cameras with 200x magnification are dirt cheap -like under 50 bucks.

Ray





fretsman said:


> Thank you both for your thoughts, they're much appreciated.
> 
> Do they not make a microscope that has retical/graduated style lenses?
> 
> ...


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## Ray C (Jul 26, 2013)

Go on eBay and look up "measurement microscope".  You'll find a variety of comprator-related products ranging in price.  Some of it is software but the packages I saw come from China.  I do not ever, ever, ever install cheap software from China on my computer.  On the one or two times I did, I got very serious viruses.  Anti-virus software will do you no good at all once you give the software permission to install itself.


Ray


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## Tony Wells (Jul 26, 2013)

I've used a USB based microscope for particle analysis and been pleasantly surprised, and I've used a 20k Deltrtonic optical comparator with edge finder. Loved that thing. But for your purposes, I believe a comparator would be an overkill. Nice to have, no doubt, but much more capability than required. Why not try a loupe with graticule? It would be a low cost experiment and might be just the thing. I have one that I use quite a bit to look at small radii and tool edges. Next up I'd go with a USB microscope. Unless you happen to run across a deal on a comparator that is.


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## DMS (Jul 26, 2013)

If you're just trying to assess condition of cutter (and not re-grinding), then I think both may be overkill. A simple loupe with a 10x magnification and a good light source may be all you need.


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## Dave Smith (Jul 26, 2013)

Dave--maybe I am a good scrounger or too cheap to buy something expensive, but here is what I use that didn't cost me over a dollar and it just took me time to come up with an inspection station for viewing tiny objects. the black spot on the base is where I lay a tiny bit or item---hope the pics will show how I can hang it on my door or set it on a bench---sorry I see that it needs to be cleaned and maybe some fresh paint. I made a simple method of adjusting the viewer height from the base....)


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## fretsman (Jul 27, 2013)

Very creative, there, Dave, and yes, I would like to be able to also "hold" the part so that it can be moved around as I have a bit of a "shaking" issue. 

Maybe I should try something like that, and set up a slide staging system with possibly some micrometer heads to move everything around.

Thanks again, all!
Dave


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## Richard King (Jul 27, 2013)

I see there is an auction up here in MN that has several Microscopes.  If anyone buys one.  I can help get it shipped to you.
This is a good auction company as I buy a lot from them.  Rich

http://auctions.machinesused.com/li...ry=838584043&subcategory=Inspection+Equipment


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## fretsman (Jul 28, 2013)

Thanks so much, Richard, I will definitely keep an eye on that site!

Dave


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## British Steel (Jul 28, 2013)

Like Dave, I have a stereo microscope - mine was rather expensive in comparison tho, £5 at a carboot! I made up a x-y stage with threaded rod, 'clicky' knobs to  let me count the thou" as I move it to measure. Works ok, but a bit fiddly! I suspect a graticle could be added at the focal plane in the optics, BUT would need to be calibrated for the different magnifications?


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## nobog (Aug 3, 2013)

Sounds like you need a _toolmakers microscope_:

http://www.ebay.com/sch/i.html?_nkw=toolmaker+microscope

JK


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## fretsman (Aug 3, 2013)

nobog said:


> Sounds like you need a _toolmakers microscope_:
> 
> http://www.ebay.com/sch/i.html?_nkw=toolmaker+microscope
> 
> JK



Well yeah, lol! Just a bit rich for my blood 

Dave


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