micrometer reading

Could someone perhaps tell me how to read this and what the measurement is? The rotating handle goes from 0 to 24 in whatever the units of measurement are (appears to be inches). Then I need to convert to mm. Thanks

Min thickness front rotors ST1100 = 4 mm
rear 6 mm

.177" (177 thousands of an inch) so 4.49MM.

ZIAMON said:

.177" (177 thousands of an inch) so 4.49MM.

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I'd go with this as I got 5,200RPM. But then I would have laid the mic over a metric ruler and say 'close enough for govt. work!'

Dean,

This is the way I would play with it to teach someone how to read it. Hopefully it helps.

The barrel that is numbered 0 to 24 is reading in .001 inches (1 thousandth of an inch). I think you will find that if you close it all the way then open it one turn will open it .025 inch. If you open it 4 full turns you will uncover the 1 on the linear scale. You now have a reading of .100 inch. 3 more full turns and you will reach .175. To get to where your picture is you are 2 thousandths past that. 0.177 inch.

More to the point of actually measuring your rotor. You would open it 8 turns (once you are used to using it you would not need to count but it may be helpful to learn) to the “2†on the linear scale. You are now at 0.200. Then you would close on the rotor. In this case you will not quite get to the .175 line on the linear scale. You are 2 thousandths short on the barrel, .175 plus .002 = .177

Thanks guys !

Since it's actually just a bit shy of the 2 line....we can get "more accurate" on your reading....it's showing .1768" 176 thousandths and 8 ten-thousandths more!

I don't think that old Lufkin has the "tenths" (ten thousands) but look on the other side of the graduated barrel. Does it have more lines? That's were the thousandths can be read.

Oil the micrometer up and wipe it with a rag. I see a small bit of corrosion on the pin. You'll give it to some grandkid some day perhaps.

Edited, .1768 not .1778 thanks dwalby.

Dean, why are you doing this exercise anyway? Unless you are using non OEM pads, the grooves cut into the OEM pads are a very good indicator of when to replace them. If the grooves are no longer there, the pads are done. Measuring the rotor for minimum thickness is another story and the mic would be handy there.

oops, I meant rotors. Better go back and change that.

ZIAMON said:

Since it's actually just a bit shy of the 2 line....we can get "more accurate" on your reading....it's showing .1778" 177 thousandths and 8 ten-thousandths more!

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oops, you are off by .0010", if you want to get it down to 4 decimal places it would be 0.1768, rather than 0.1778"

dwalby said:

oops, you are off by .001", if you want to get it down to 4 decimal places it would be 0.1768 or 0.1769"

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now your splitting hairs (.004)

Al, I edited my original post to make it clearer. I wasn't talking about the last 0.0001" digit being an 8 or a 9. I was referring to the 0.1778" value being off by 0.0010". Ziamon added the 4th decimal place, but inadvertently added one too many thousandths to the final value.

The conversion really screws it. Buy a meter micrometer... you will regret it

No conversion confusion if you have the Honda manual. It gives the rear disc service limit in inches as well. 0.24 Front is 0.16

Tdinova said:

The conversion really screws it. Buy a meter micrometer... you will regret it

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Meter micrometers are big things (I saw one today for the first time that must be close to that size). I'm not sure he needs one that big. :bow1: But they do make mikes that are digital and read in inches or mm. Not sure of the cost though.

SMSW said:

Meter micrometers are big things (I saw one today for the first time that must be close to that size). I'm not sure he needs one that big. :bow1: But they do make mikes that are digital and read in inches or mm. Not sure of the cost though.

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About $20 https://m.harborfreight.com/digital-micrometer-68305.html


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Ashley said:

About $20 https://m.harborfreight.com/digital-micrometer-68305.html

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hmmm, says $34.99 on my screen.

FWIW, a few years ago HF had the Pittsburgh digital caliper on sale for $10 or so, decided to give it a try. Compared it to my analog dial calipers (Mitutoyo) and found it to be fairly consistently off by about 0.02-0.03mm measuring valve shims. Returned it, since that was enough error to be off by one shim size and I already owned more accurate calipers (but not digital). So depending on your accuracy requirements the cheaper units may be worth buying, or maybe not.

As I get older the idea of a digital readout vs. having to kneel down and squint at the kind like Dean showed is more appealing.

SMSW said:

... But they do make mikes that are digital and read in inches or mm. Not sure of the cost though.

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The Mike I know does manage digital data, can read, but he is pretty expensive....approaching $100/hr. ;-)

dwalby said:

So depending on your accuracy requirements the cheaper units may be worth buying, or maybe not

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Agreed, you get what you pay for. Probably good enough for rotors though. Here's mine.



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A measuring contest but in a different direction.

https://www.harborfreight.com/catalogsearch/result/index/?dir=asc&order=EAScore,f,EAFeatured+Weight,f,Sale+Rank,f&q=micrometer

Perhaps he meant the vernier calipers? $ 17.99 right now.