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saltytri
04-30-2010, 05:30 PM
I note that the 0-1" version has curved jaws that are apparently meant to accommodate the measurement of the inside of a cylinder. The 1-2" version, however, has flat-faced jaws. Am I missing something here, or is this instrument meant to measure only the distance between surfaces that are parallel?

luthor
04-30-2010, 07:22 PM
More information required here.

saltytri
04-30-2010, 07:53 PM
Fair enough. Look at the illustrations here for 145-193 and 145-194:

http://www1.mscdirect.com/PDF/2008/580480.pdf

The jaws on the 193 are pins, so they can fit against the inside diameter of a tube or a ring. The jaws on 194 are ground flat so I can't see how they could provide an accurate measurement on the inside of a tube or a ring.

Look at the picture of the "Holder 300400" to see what I'm trying to say. If the 145-194 were used in this way, it would yield too small a measurement because the surfaces of the jaws that contacts the ID are flat:

http://www.mitutoyo.com/Images%5C002%5C278%5C145-194.pdf

luthor
04-30-2010, 08:14 PM
I have used these before and the jaw surfaces are not flat but have a radius to allow accurate I/D measurement within the measuring range.

Machinist-Guide
04-30-2010, 11:48 PM
I have used these before and the jaw surfaces are not flat but have a radius to allow accurate I/D measurement within the measuring range.

The picture don't show the radius very well but it't there.

saltytri
05-01-2010, 11:11 PM
Thanks for the help, gents. Mine is still wrapped in Mitutoyo's clear plastic and I sure can't see the radius. I didn't want to open it up if it's not what I thought. But it sounds like it will do the job that I need.

oldtiffie
05-02-2010, 12:38 AM
I note that the 0-1" version has curved jaws that are apparently meant to accommodate the measurement of the inside of a cylinder. The 1-2" version, however, has flat-faced jaws. Am I missing something here, or is this instrument meant to measure only the distance between surfaces that are parallel?

Will this help - all makes are similar?

https://www.machineryhouse.com.au/Products?stockCode=Q135

Your Old Dog
05-02-2010, 06:53 AM
OH NO! I DON'T HAVE ONE OF THOSE YET!

https://www.machineryhouse.com.au/images/11534.jpeg

Richard-TX
05-02-2010, 09:25 AM
The pin type inside micrometers have a .2 - 1.2 range.

The jaw type is a 1 - 2" range. The jaws are radiused...they have to be.

saltytri
05-03-2010, 10:20 AM
Based on the reassurances here, I screwed up my courage and broke open the plastic bag. Yes, the jaws are radiused, just enough to do the job.

Thanks, all!