Donation: Inside Micrometer 50mm~800mm +- .003mm (.00012")

Machine Shop
#1

Thanks @thatguy Steven Martin, who got his boss Mark Church to donate this like Like New set, I doubt it was ever used. A new Starrett set like this is >$800. A fantastic addition. We are developing a serious and extensive collection of measuring tools that are Starrett, Brown & Sharp, or Mitoyo. Professional industrial quality tools. We should probably send these out to verify they are set properly considering the accuracy these have and the range: 2" to 31.5" in English

Starrett 124MDZ Solid Rod Inside Micrometer Set

The Starrett 124M Solid -Rod Inside Micrometer Sets are the most popular inside micrometers because of their lightness, ease of use, and range. They are very useful for measuring inside diameters of cylinders and rings and measuring parallel surfaces. The desired range is obtained by assembling rods and spacing collars to the micrometer head. M 50-800mm, 0.01mm Grad, 124MA/134MC Rods with Case.

Thank you!

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#2

Update, Steve says he thinks he can get the Metrology Lab at his work to check calibration for us.

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#3

I’d love to see a class on the appropriate use and application of these measurement devices. Any idea if that might happen?

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#4

Actually this has motivated to do actually start working on it today.

We need to get a cabinet dedicated to our inspection and measurement tools that or a drawer cabinet. Our tools are scattered all over the place. Other than a basic 6" caliper kept at each machine, the rest I’d like to see centrally stored and get the Surface plate into regular use.

We lots or micrometers (OD & ID), calipers, telescoping gauges, dial indicators (test & plunge), gauge pins, gauge blocks, height gauge, precision angles, sine bar, etc. We can have a true inspection station.

My preference would be for us cabinet that is attached to the surface plate so the tools are stored with it and can be rolled to where ever needed. I have a set of large casters for it to replace the small ones that make it hard to roll. Need to get some help to lift the surface plate out so it can be inverted and the new casters welded on (@TBJK might be sweet talked into welding them on … I know they’d never fall off! [“tack weld” is a concept that eludes him] :smile:) Welcome other ideas or proposals. But do want the tools centrally located so they can be found and monitored for abuse or damage.

Oh and thanks to Kris Anderson @Kriskat30 today, I brought in another piece of canvas for the cover for the Slip Roller that matches the Brake and Shear. She quickly surged the raw edge. That waaaay oversized heavy green canvas tarp is now folded and under a work table. Musch easier to uncover and use now.

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#5

60,000 psi strength … more “i”, more strength! :smiley:

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#6

Don’t encourage him!

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#7

I have some diamond plate that we can hot rod the roller cabinet up with =)

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#8

Lol. Stronger than the base metal. When I stick I like to use 7018.

Yes my tack welds are welds in other people’s eyes.

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#9

I’ve got some 8018 Atom Arc in 1/4" rods that I was given. Used it to test out my new welder years ago at 250 amps and it was barely hot enough to keep an arc. That was super roasty even through my welding jacket. (You’re welcome to a dozen rods or so if you want some.)

(edit: to answer Walter’s next question: 220V 50 amp receptacle about 2’ away from the main breaker panel, 6ga wire feeding it off a dedicated 50A breaker.)

#10

My pleasure David. Anytime

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#11

.00012" per inch sounds tiny. Ima have to bring a ring gauge over and try it sometime. Or something.

#12

The smallest size is 50mm/~2". We have a Starrett Inch set that will go down to 1" thru about 8"

But we have some .0001" mics that go to 4" that can also be used to cross check.

#13

What would you consider to be our “reference standard”?

#14

My acronym of a name “TLAR”

“That Looks About Right”

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#15

For some of the mic’s they have either the 1", 2", or 3" set bars, there’s a couple of rings. We have the gauge pins and gauge blocks that could be used and even stacked for the ±.001" instruments. But other than those we don’t have a “reference set” or a set that is calibrated.

As I said, what I use to check something close is the .0001" mics after verifying they set to zero, then opening to set dimension and checking against that. Getting reference standards and maintaining them, for say a range of 1" ~ 12" would cost several thousand dollars. Individual calibration rings, a single 4" ring is $639. Note that they are usually for only either outside or inside checking.

Here’s a set that will do various tools/items up just 6", primarily outside checks, $1,300..

Here’s a set that is only 4" max and is only good to .001". Generally rule is calibration standard should be 1/10th accuracy for tool calibrated and absolute minimum of 1/4th. When a calibration lab does an instrument that measures in .0001" the reference set is probably ±.00001" or .00002" or 20 millionths. Optical flats for verifying flatness and parallelisms of the anvils on mics and calipers

For our purposes if we have a calibrated tools like the $1,500 Mitoyo set we’d be fine. But that set would strictly be limited access to just a few people authorized to check and adjust tools. They are easily damaged or abused. Would also need to get some optical flats.

This big inside mic set, it would have to be sent out for calibration (which we may get done) if needed, because to buy standards to cover it’s range would be crazy expensive.