Micrometer

[jaydee325]

Found this in Stepdads tool box while going through things to have an estate sale.

Anyone heard of GAT? My first thought is that this was a novelty item. It is 0" to 0.5". Seems to be off 0.1" over full range. There is a screw on the end that might allow adjustment, but the barrel rotation is not smooth and needs cleaning.

Based on the fact that stepdad retired in the early 80's, I'm guessing this is something from the 60's or 70's.

 

[ljjhouser]

Nope, never heard of GAT tools. Wondering if it used to be part of General Tools. Also, the knurling and scales look a little rough. I was thinking it was from the 40s maybe. .1 error is a LOT for a micrometer.

 

[jmc]

Does it read zero when fully closed but strays by .100 when fully open?

Screw on the end might be friction adjustment if it has a clutch.

 

[jaydee325]

Does it read zero when fully closed but strays by .100 when fully open?

Screw on the end might be friction adjustment if it has a clutch.

No, reads 0.1" when fully closed and maintains that throughout the range.

I don't need this micrometer, was just interested in maybe finding out what it is and when it was manufactured. I've got a perfect 0-1" micrometer for the times I need one. Actually, I grab my digital vernier caliper for most of my uses.

 

[Rockbadchild]

what your step dad did for a living ? its a common tool for quality control in saw mills to measure the thickness of planks... although this one doesn't open very wide ...

 

[jaydee325]

Stepdad was the head mechanic for a small municipality. I remember my mom's chagrin as he was frequently called out at all hours to fix police, fire, and street dept vehicles. He liked what he did though!

This curious 0"-0.5" micrometer will just be hung on a wall as a conversation piece. It's not even comfortable to hold to get a measurement! Basically, I was just wondering why something this small would even exist! Again, I'm thinking it was a novelty piece.

 

[MapleLeafFarmer]

I am going to bet you a big fat steak (or gallon of gas) you are on the wrong track.

GAT is not the maker of the tool.... it is the business that used/owned the tool. Stamped their initials and factory location to prevent theft/loss.

I have a very similar tool we used in the 50's and 60's to mic out flat stock and structural steels used in manufacturing. Highly expensive back in the day, coveted, and prized versus today where every Tom/Dick and Harry has tools like this in their loading rooms, shops, tool boxes, etc...

Was your Stepdad a welder/fabricator/engineer?

A History of Forward Thinking, Satisfied Clients and Long-Term Employees​

Born out of engineering expertise and passion for efficient design, GAT was founded by the current owner’s grandfather in 1958 in St. Louis, Missouri. From the beginning, we put our focus on creating custom finishing solutions and process lines for companies in North America. GAT was at the forefront of industry change in the 1960s, innovating and creating patented technology and processes. We’ve always had a strong focus on family and our employees, which is why people come to work for GAT and stay here for many years.

 

[Rockbadchild]

I am going to bet you a big fat steak (or gallon of gas) you are on the wrong track.

GAT is not the maker of the tool.... it is the business that used/owned the tool. Stamped their initials and factory location to prevent theft/loss.

I have a very similar tool we used in the 50's and 60's to mic out flat stock and structural steels used in manufacturing. Highly expensive back in the day, coveted, and prized versus today where every Tom/Dick and Harry has tools like this in their loading rooms, shops, tool boxes, etc...

Was your Stepdad a welder/fabricator/engineer?

the graving looks factory made to me it’s not engrave or punch stamp that’s for sure … i agree it was more then a novelty tool

the OP step dad was a mechanic

 

[WranglerX]

Probably can be recalibrated for accuracy by anyone familiar with precision measuring tools... Indeed the GAT appears to be manufacturing stamped...

 

[MapleLeafFarmer]

Probably can be recalibrated for accuracy by anyone familiar with precision measuring tools... Indeed the GAT appears to be manufacturing stamped...

yes mine has 2 adjustments to reset to zero before every use and clutch to make consistent pressure on each measure. 70+ year old tool and still works like new.

I have even kept my instructions in the box pristine. One day it may even be worth...... nothing as most people gone digital and disposable versus quality made tools and other things

Mine was a gift from a steel supplier (I think I remember it was a Christmas gift) that was given to us with our name stamped in it in recognition of being a good customer. Allowed us to confirm what they were supplying was actually what was bought.

I guess sorta like today when we a hat or coat if we are lucky for being a good customer just not as usefull.

 

[Lineman North Florida]

I googled GAT St Louis Mo. and it came back with a manufacturing company called General Automatic Transfer, just outside of St Louis, might be a clue or somewhere to start.

 

[Root Cause]

Stepdad was the head mechanic for a small municipality. I remember my mom's chagrin as he was frequently called out at all hours to fix police, fire, and street dept vehicles. He liked what he did though!

This curious 0"-0.5" micrometer will just be hung on a wall as a conversation piece. It's not even comfortable to hold to get a measurement! Basically, I was just wondering why something this small would even exist! Again, I'm thinking it was a novelty piece.

It would be handy to keep in your pocket if you had to measure gauge stock, angle iron thickness, or feeler gauge stock on a routine basis. Typically, there would be a small hole in the barrel where a wrench would spin the barrel to align it back to zero when fully closed.

Sounds like a good piece to save as a keepsake.

 

[Otgaugres]

Guessing it’s off 1 graduation which would be .001”. That’s still alot for a micrometer. Make sure there is nothing on the measuring faces of the tool. Old trick is to lightly close it on a piece of paper and drag the paper out to clean the measuring faces. If it’s still off, the graduated barrel can be rotated to bring it into spec. There should be a small hole on the barrel for a spanner wrench. Most micrometers come with the correct spanner wrench for adjustment.

 

[marhar]

I am going to bet you a big fat steak (or gallon of gas) you are on the wrong track.

GAT is not the maker of the tool.... it is the business that used/owned the tool. Stamped their initials and factory location to prevent theft/loss.

I have a very similar tool we used in the 50's and 60's to mic out flat stock and structural steels used in manufacturing. Highly expensive back in the day, coveted, and prized versus today where every Tom/Dick and Harry has tools like this in their loading rooms, shops, tool boxes, etc...

Was your Stepdad a welder/fabricator/engineer?

A History of Forward Thinking, Satisfied Clients and Long-Term Employees​

Born out of engineering expertise and passion for efficient design, GAT was founded by the current owner’s grandfather in 1958 in St. Louis, Missouri. From the beginning, we put our focus on creating custom finishing solutions and process lines for companies in North America. GAT was at the forefront of industry change in the 1960s, innovating and creating patented technology and processes. We’ve always had a strong focus on family and our employees, which is why people come to work for GAT and stay here for many years.

https://gat-systems.com/about/

I bet you are correct.

 

[Gord Baker]

Found this in Stepdads tool box while going through things to have an estate sale.

Anyone heard of GAT? My first thought is that this was a novelty item. It is 0" to 0.5". Seems to be off 0.1" over full range. There is a screw on the end that might allow adjustment, but the barrel rotation is not smooth and needs cleaning.

Based on the fact that stepdad retired in the early 80's, I'm guessing this is something from the 60's or 70's.

 

[Bearsden]

FWIW, GAT is Dutch for "hole".

 

[jaydee325]

I unscrewed the thimble from the sleeve and removed the screw on the end of the thimble. This allowed the spindle to be removed from the thimble. Bad news. The spindle was threaded into the sleeve and the screw acted at a lock for puposes of calibration. The threads on the spindle that screwed into the thimble are bad. Threads on the spindle for turning the thimble in and out to take a measurement are fine.

Bottom line, this little micrometer can't reliably be calibrated anymore. Definitely just a conversation piece at this point.

 

[jones6780]

Smaller mics were generally used to measure tubing wall thickness or sheet metal gage thickness. Is the fixed anvil rounded?

 

[jaydee325]

Smaller mics were generally used to measure tubing wall thickness or sheet metal gage thickness. Is the fixed anvil rounded?

No. It's not a quality piece. As I've said before, It's pretty much a novelty item or something a salesman handed out at Christmas.

The discussion has been fun though! And for me, the family connection is worth putting it on my tool board in the shop to talk about.