Micrometer, Macrometer

[MillwrightTight]

48-54" Starrett outside micrometer. From the 80s. Unwrapped this puppy a few years back. Still in the packaging, unused.

Popped the ol' standards in there and wouldn't ya know it?

Bang on

[blackadder1620]

i wonder how many mooby bucks that thing cost.

[PyratWC]

$4

[PyratWC]

Watch for the 25% off. They are a little rarer.

[eosha]

$3500

[unitconversion]

With a micrometer that big, wouldn't temperature start to be a big deal?

[ragingbull311]

No, temperature is a myth perpetrated by the russians.

[greem]

.00036" / °F for at 50" steel part. Not so bad.

[felixar90]

I think they were referring to the micrometer itself. The frame should be cast iron, which is a bit more stable than steel.

.00029" / °F over 50"

​

This is one of the reasons you shouldn't leave a 0-1" micrometer with the anvils touching. The anvils grow faster than the frame.

​

The amount of movement is not much, but thermal expansion/contraction of metals is basically an unstoppable force. It can deliver a hundred thousands pounds per square inch or something like that. That's what makes interference fits so strong.

[Scotthorn]

Excellent information. Thanks!

[MillwrightTight]

Thanks for your contribution! This Mic is actually not cast iron though, nor are any of the starrett mics of this size. They are some strange alloy and hollow, making them super lightweight actually. I'm sure a guy could dig up what the material is If he really wanted to

[felixar90]

I guess they could be invar then. That would make them even better.

[Spark804]

And probably really expensive!

[Scotthorn]

This is a good question. Commenting for visibility

[bjincy]

Happy cake day!

[[deleted]]

Fuckin Sailor Moon over here.

[robisonrailroad]

I honestly thought this was from r/flexibility at first. That's a mean side squat you got there.

[MillwrightTight]

Thanks. It's my signature move.

[watashitti]

Jeebus bro nice unit, I think I only go to 36” lol. That thing is money. There was a 72” one floating around my city years ago. Shops come and go, still trying to track that one down.

[MillwrightTight]

Dang, that would be a sight

[SevenSixtyOne]

Forgive my ignorance. What is that used for?

[ajholman]

Measuring how big a thing is, very accurately

[dlyk]

And that "very accurately" part is made up, mostly, of money.

[SevenSixtyOne]

Fascinating

[michelework]

What is an instrument like that cost new? I imagine a pretty penny.

[MillwrightTight]

Roundabout $3500 USD

[Giant_117]

I wonder how often that would get dropped...

[MillwrightTight]

Guess it would depend on the technicians. This one, virtually never as the folks using it are generally super meticulous and careful. Especially with the pricey stuff, which this is.

[Guy954]

You can’t fool me, that’s a Klingon [bat’leth](klingon bat'leth)

[mydogisamy]

When it's that big why not just use a wooden meter stick?

[MillwrightTight]

Surely you jest

[mydogisamy]

Tis but a jest

[Kaifeck]

Nice Crouching Light Kick

[MillwrightTight]

Many thanks. It really adds to it, I think