My first precision tool!

[metaleltr]

My friend gave me the 0-1" Craftsman micrometer yesterday. it had been sitting in the top of a hand carry toolbox for years, is was slightly seized when i found it and had to be zeroed. After some lubrication and exercising it is pretty smooth! Just a few questions, Any ideas on age? There are no model numbers or date codes, i have looked! What is the best way to store, Scale at zero or part way open? Finally, what is the purpose of the knurled black ring between the scale and the c frame? It spins freely with no apparent purpose.

 

[PBCampbell]

No idea on age. Probably made by General(or whoever made stuff for General). Do not store with the faces touching, leave it open just a touch. The black ring is the spindle lock, if its spinning that's not good, should only go a half turn clockwise to lock.

 

[metaleltr]

Well I see know way for the spindle lock to lock anything, the only indication of age that I have is that is must be older because it has a machined c frame as opposed the forged or cast frame on the newer ones, also new ones have either a digital or analog readout as opposed to actually reading the mic scale

 

[metaleltr]

Anyone have any information ion how the spindle lock works? i have fiddled with it and have not been able to get it to function.

 

[Roots]

Congrats, remember to check the calibration of it though, depending on how sensitive you need it to be.

 

[metaleltr]

I'm no machinist, 1/4" hex keys reading within .001, close enough even if that error is in the mic. I'm currently basing it's accuracy on it being accurately zeroed.

 

[Provincial]

The spindle lock is a simple eccentric ring. The center hole is drilled offset from the outer register. It may be that someone left it tightly locked for years and the plastic has taken a set. If you unscrew the spindle and remove it the lock ring should just fall out and you can examine it for damage or wear.

I have seen some installed backwards and they did not work, so that is worth a try. That was on other brands, so it may not apply.

 

[metaleltr]

How would I go about unscrewing the spindle? I don't want to ruin this thing, it works great except for the lacking spindle lock.

 

[Roots]

I'm no machinist, 1/4" hex keys reading within .001, close enough even if that error is in the mic. I'm currently basing it's accuracy on it being accurately zeroed.

I wouldn't concern myself than either. Congrats again!

 

[A_Pmech]

It's a re-branded Scherr-Tumico.

 

[rlitman]

It's a re-branded Scherr-Tumico.

Yep, and you know you have a good one, when it has a carbide faced anvil.

 

[Provincial]

To remove the spindle, simply unscrew it all the way.

 

[Shadowdog500]

I'm no machinist, 1/4" hex keys reading within .001, close enough even if that error is in the mic. I'm currently basing it's accuracy on it being accurately zeroed.

May want to check it against a few feeler gauges, but I'm sure it is good enough.

FYI I was taught to store micrometers with the jaws slightly open, supposedly puts less stress on the micrometer during temperature changes.

Chris

 

[Trucky]

FYI I was taught to store calipers with the jaws slightly open, supposedly puts less stress on the micrimoter during temperature changes.

Chris

This had me awfully confused for a while there, but I get what you mean now

It's a re-branded Scherr-Tumico.

Winner. I don't mind ST's mics... the indicators I do fine without, even though I've found a few older ones of okay quality. I do like the mostly all the ones I have seen were US made... but that doesn't mean they're up to BesTest quality, unfortunately.

Do not store with the faces touching, leave it open just a touch.

Carbide anvil and spindle faces means you really don't need to worry about the faces touching. Just don't screw the thing together like a c-clamp and let it sit there.

Also, clean the faces with some stronger paper you have lying around and give them a *VERY* light touch of oil, then clean them off again. Starrett makes good instrument lubrication.

 

[spongerich]

Many "real" machinists will tell you that if it was rusty it's no longer accurate and you should toss it into the scrap pile. Assuming you're OK working within one or two thousandths, you'll probably get years of good service from her.

A good way to check the accuracy is to buy/borrow a couple of Johansson gage blocks. Even shop grade ones are accurate to around a hundred thousandth of an inch.

Fun fact.. good Johnanssen blocks are so smooth that if you clean them and stick them together, they're very difficult to pull apart. It's as if they're magnetic. It's unknown exactly why this occurs but materials scientists believe that molecular attraction plays a large part because the surfaces are so perfect.

 

[Harley94]

Most smaller mic's came with a calibration disc to check them. Most anyone that bought a micrometer new will have one you can use. Back it off about .020 when you store it.