How do you use a micrometer?

[skogkatt007]

I'll give my method. I would ask that if you disagree (and I'm umder no delusion that mine has to be the right way), please give an explanatuon of why yours is better. I worked in a shop for a short while, and have seen it done differently.

Differences in measurement could arise for a number of reasons I'm guessing. Material, it's finish. Not to mention environmental factors, which I guess can be ignored except for extreme fine measurement. I don't know. You tell me.

Generally I think I will only create enough pressure between "hammers" so that I can lift a few ounces. I won't get any more specific then that. I'll only say that 8 ounces is too much. I hope that's descriptive enough.

Am I an idiot? Well obviously! Which is why I'm asking LOL.

 

[Huub Buis]

The micrometers have a ratchet at the end of the knob that should be use to tighten them. This ensures the pressure is always right and the same so multiple measurements give "the same" results.

 

[GrifterGuru]

As per @Huub Buis use the ratchet. The ratchet is designed such that an equal pressure is used for each measurment and thus you get an equal, repeatable measurement. In theory.

 

[SouthernChap]

As has been said, the ratchet has got to be the go-to method of ensuring reasonably repeatable measurement.

However, not all mic's have ratchets. Most modern mic's do these days, but older models may not.

So not /thread just yet I reckon.

 

[Jake M]

I find that if you tighten with the ratchet, (with a micrometer that is proven accurate), you can use that point as a datum, you can "repeat" that measurement without the ratchet, and thereby train your fingers how tight to make your other micrometers that DON'T have the ratchet, and get them all to repeat to each other. Kinda like using a torque wrench more than what's required, to keep the training up to date for your click elbow.

 

[benmychree]

And we are told that we should only use 3 clicks of the ratchet to assure constant readings, I have not heard how to use the similar friction thimble, all of mine are ratchet type, but I rarely make use of that feature, relying on feel only.

 

[GrifterGuru]

And we are told that we should only use 3 clicks of the ratchet to assure constant readings, I have not heard how to use the similar friction thimble, all of mine are ratchet type, but I rarely make use of that feature, relying on feel only.

Funny, I was taught to spin the ratchet three times, no more, and that would ensure it was seated and give the correct reading.

Strange how teaching methods / advice differ.

 

[benmychree]

Funny, I was taught to spin the ratchet three times, no more, and that would ensure it was seated and give the correct reading.

Strange how teaching methods / advice differ.

When in doubt, read the instructions; I never did ---

 

[rabler]

Not to mention environmental factors, which I guess can be ignored except for extreme fine measurement. I don't know. You tell me.

Heat from milling or lathe work can definitely cause things to expand by a few thou.

 

[benmychree]

It would take quite a bit of heat to cause that much expansion, depending on the material, this is one reason why running coolant on a machine is a good thing.