Starrett Micrometer Caliper Set #224 AA

[whisperinsam33]

I got the above set in a trade. Its accuracy is certified by General Electric Installation & Service Engineering, and is annotated as .007 mm.
It lives in a cloth covered box and is in pristine condition (the outer portion of the box is worn from age). The tool and its extensions look as if they've never left the box.
The accuracy and the NATO Standardization Office (NSO) certification are also etched on the tool arc at each location where it encircles the steel cylinder. Can be seen by enlarging pic.

Could someone tell me if the accuracy rating (.007) is decent? Also, could someone give me a ballpark value for this precision tool? It is way out of my league.
Thanks, sam

 

[LNKMK8]

Look on eBay sold items... Looks like somewhere around $80

 

[Jason280]

0.007mm is equal to 0.000276"...

 

[LeeG]

.007mm is .00028". Factory new they are accurate to .00015". There are a ton of these on ebay, and the price range is huge. This looks like a decent kit, so might sell for $200 or maybe more.

 

[matt stott]

Curious where you are getting the 0.007mm from? It looks (to me) like the 007 number is the asset number for that particular mic set from GE. It has a standard calibration sticker, but without a date it looks to be a "production" unit- not something that got calibrated on a regular schedule.

Since that is an inch micrometer set, I would assume any certification and testing would also be in inch measurements- and that mic is certainly more accurate than 0.007 inches. (and why I believe the 007 to be the in-house serial number- and a cool one at that!).

Nice set, by the way.

Matt

 

[davethorik]

Nice set but pretty much worthless in actual use.

 

[mowkep]

Unfortunately you need to have mics sent out for recalibration.

 

[X1 Mike]

Unfortunately you need to have mics sent out for recalibration.

Obviously the OP doesn't really have experience with micrometers so it's silly to suggest he needs recalibration. Unless he is working in an ISO certified shop he is just fine with those mics and checking them to the standards provided. Even if he was in an ISO shop they would just provide him with a sticker that says "For Reference Only".

When it comes down to it mics are just guessin sticks.

 

[Dingleburry]

I would also say the 007 is a serial number or unit number. All our scales and test equipment have unit numbers attached, so we can call the calibration/service company, and say this scale with unit number *** is reading wrong. They can look up the make/model/calibration history, past problems etc etc. And order/bring parts/tools etc. It would most likely have a paper with its actual specs on it. Also so they dont miss any on yearly/quarterly inspections. They would have a master list of all units/unit numbers

 

[Doug Arthurs]

Nice set but pretty much worthless in actual use.

Not sure why you would say this. I use similar all the time. The set comes with standards so checking and adjusting is pretty easy. I can't tell if these are tenths reading but if not they would be accurate to .001". The certificate sticker on there really has no value at this point.

 

[GRB]

The 007 is definitely the internal asset number of that mic. The "cert" is just initials of their metrology department saying it is certified for use with no date or expiration.
Interchangeable mandrel mics are nice when you want one mic to do measurements thru a larger range but a lot more work to use.
People will always pay a bunch more for an item that is Starrett even when there are better options for less money.

 

[davethorik]

Not sure why you would say this. I use similar all the time. The set comes with standards so checking and adjusting is pretty easy. I can't tell if these are tenths reading but if not they would be accurate to .001". The certificate sticker on there really has no value at this point.

I'd rather be making chips than swapping rods and trying to calibrate it on the go. No tenths. No carbide. No thanks.

Individual used mics 0-4" would be cheaper and more convenient.

 

[X1 Mike]

Not sure why you would say this. I use similar all the time. The set comes with standards so checking and adjusting is pretty easy. I can't tell if these are tenths reading but if not they would be accurate to .001". The certificate sticker on there really has no value at this point.

I spent the first 18 years of my working life in various Tool & Die shops and I can honestly say that I've never seen anyone use a micrometer with interchangeable anvils. Keep in mind this was in 5 shops and have probably had 500 co-workers.

If you rarely need to measure precisely and only rarely use mics those would be great to give a really good estimate of size.

I used to run a surface grinder and routinely did aircraft work holding tolerances of 0.00005"

 

[whisperinsam33]

Thanks to all for the great responses. I'm going to sell it on CList and will be sure to use the info provided.

 

[ganymede]

I spent the first 18 years of my working life in various Tool & Die shops and I can honestly say that I've never seen anyone use a micrometer with interchangeable anvils. Keep in mind this was in 5 shops and have probably had 500 co-workers.

If you rarely need to measure precisely and only rarely use mics those would be great to give a really good estimate of size...

In old catalogs those mics were marketed to small shops who didnt need to invest in a full set.

 

[X1 Mike]

In old catalogs those mics were marketed to small shops who didnt need to invest in a full set.

I'm talking individual machinists. I only saw them in larger sizes for shops that didn't have a good supply or I did work with one guy who had some that were 10+ inches and he only used them when the shop mics were in use. I never worked with anyone that had at least a year under their belt that didn't have a personal set of 0-4" mics.

 

[ganymede]

I'm talking individual machinists. I only saw them in larger sizes for shops that didn't have a good supply or I did work with one guy who had some that were 10+ inches and he only used them when the shop mics were in use. I never worked with anyone that had at least a year under their belt that didn't have a personal set of 0-4" mics.

Ah ok, gotcha.
For the op heres a similar mic in the 1938 catalog..
View media item 95543and a different model made for the govt..
View media item 95544

 

[larry_g]

To many are looking at this set through the eyes of a machinist who has to generate a precision part. For the mechanic in the field who has to discern if the piston sent out is a .010" or .030" over they are just fine and get the job done. Not something I'd use daily but if one infrequently uses a micrometer and has to discern something is +/- a couple of thousands then they work. Hell a carpenter makes due with a tape measure.

lg
no neat sig line

 

[X1 Mike]

To many are looking at this set through the eyes of a machinist who has to generate a precision part. For the mechanic in the field who has to discern if the piston sent out is a .010" or .030" over they are just fine and get the job done.

Funny story...well it was funny to me. After spending 18 years as a machinist I wanted to work on motorcycles so I went to the Motorcycle Mechanics Institute and one day in machine shop class we were measuring cylinders and my instructor saw me whip out my scale and asked what the hell I was doing. Granted this instructor was pretty good at boring and honing cylinders but he wasn't a "machinist". I said I was just getting close. I then proceeded to bet him that I could measure a cylinder within .005" with my scale. I whipped out my eye loupe and gave him the size I came up with. I was within .003" Today I couldn't get nearly that close.

 

[Indexmill]

Back when I could actually SEE, I could easily use a good Starrett satin scale to measure to .010 all day long.

 

[mowkep]

Obviously the OP doesn't really have experience with micrometers so it's silly to suggest he needs recalibration. Unless he is working in an ISO certified shop he is just fine with those mics and checking them to the standards provided. Even if he was in an ISO shop they would just provide him with a sticker that says "For Reference Only".

When it comes down to it mics are just guessin sticks.

He was referencing old calibration stickers which at this point are useless. So no, I'm not being silly.

 

[X1 Mike]

Unfortunately you need to have mics sent out for recalibration.

Obviously the OP doesn't really have experience with micrometers so it's silly to suggest he needs recalibration. Unless he is working in an ISO certified shop he is just fine with those mics and checking them to the standards provided. Even if he was in an ISO shop they would just provide him with a sticker that says "For Reference Only".

When it comes down to it mics are just guessin sticks.

He was referencing old calibration stickers which at this point are useless. So no, I'm not being silly.

You said "Unfortunately you need to have mics sent out for recalibration."

I still say that it's silly to suggest that for someone that is not working in an area that requires measuring tools to be calibrated. Just check them to the standards, adjust as necessary and go on with your day.

 

[mowkep]

I assumed he was looking for information to sell the items, not actually use them. In which case, if was using the calibration stickers as a selling point, it would be unreliable. Thanks

 

[davethorik]

To many are looking at this set through the eyes of a machinist who has to generate a precision part. For the mechanic in the field who has to discern if the piston sent out is a .010" or .030" over they are just fine and get the job done. Not something I'd use daily but if one infrequently uses a micrometer and has to discern something is +/- a couple of thousands then they work. Hell a carpenter makes due with a tape measure.

lg
no neat sig line

That's why there are dial calipers.
These mics don't really have a place in anyone's kit except collectors. Or a home machinist who doesn't have anything better.