Micrometer question

PJH

Well-known Member
I see some of these that have a handle included in the set. Most sets on Ebay don't have the handle included, and I wonder how they would be used to measure a hole diameter that you couldn't get your hand down into.

Just curious. . .

Thanks
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They wouldn't.

You would be forced to buy a handle or obtain another type measuring device. One that comes to mind is a Dial Bore Guage.
 
Mike, is there an advantage of one or the other of the two types? Yours is tubular, and the one I pictured is solid rod. They make two types for some reason - just wondering why.

Thanks
 
In trade school the test for using them was measuring a bore that was about 6" diameter to .0005. None of the 28 students in my class passed on their first try, some never did pass. As you have already guessed the smaller the hole the more difficult they become but they are difficult to master in any size bore. Even bigger bores can be a problem if your after dead to nuts because the dang mic gets longer as it warms up in your hands and messes with your readings. I guess the handle would help with that but we were taught to leave the handle in the box.

Dont mean to drag this O.T. and I like nice old tools but my inside mic set hasn't seen the light of day for 10 years, they are just too darned slow and hard to use.
For coarse work an outside mic and a set of snap gauges beets the heck out of an inside mic for speed. When the bore needs to be right on it takes a lot less time to set up a dial bore gauge and using it is as easy as falling down. The import clone dial bore gauges are cheap, well made and accurate (as long as you stay away from the cheapest of cheap)

Guess it would also depend on what your doing, my use is general repair work on the lathe and boring cylinders for oversize pistons and pressed in sleeves on a horizontal boring mill, all .0005 tolerance work. Just something to think about before you take the plunge on onside mics.
 
PJH.
I have used both types in my tool and die days and they take a good deal of practice. The handle is really kind of lame. The jaws grip the mic barrel and aren't very rigid. You have to change it a little at a time and keep trying till you find the exact center of the bore in two directions. Patience required. I think the rod type you have can be calibrated by changing the length of each rod. The tubular type must be ground to length, each one, because you can only adjust at the barrel. So each one has to be the correct length. Like Butch says, they don't get used often. I got these from a pawn shop just because I liked them and thought I may need them some day. I use my Mitutoyo verniers a lot more. Bought them when I was an apprentice about 45 years ago.
 
Thank you all for the replies. I don't own the set in the picture - I pulled that image from an Ebay posting. It's nice to hear from people who have actually used tools like this. I thought it would be difficult to find the center of the bore, especially without a handle, and I never thought of your hands warming things up and fooling with your results.
 

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