Identity of micrometer
- Thread starter Tomc938
- Start date
Well that doesn't look at all suspicious!
I'm working on a PM research steam engine, and my cheap (very old) Chinese micrometer seems to make everything about .003 smaller than it should be. So a "new" reliable 01" mic is in the works.
If there is one tool I would buy from Mitutoyo it's the 0-1" micrometer. I see them at pawn shops some times. $35 is a good price for that micrometer unless it was used as a C clamp. That micrometer will outlive you if you take care of it.
Ok to be honest there is a lot of stuff I would buy from Mitutoyo.
Ok to be honest there is a lot of stuff I would buy from Mitutoyo.
Have you calibrated it? If it is out 3 thou routinely, it prolly just needs calibrating. With most micrometers, you do that simply by turning the barrel to align the zero marks.
Measure zero with clean anvil surfaces, make a note of what it says, back the thimble off a turn or so, turn the barrel using a small hook wrench the amount it's out. (the hook wrench prolly came with it - make one if not)
Retry until you get it right.
All the above said, get the mitutoyo anyway. Thats a good price for an old one that works. It will prolly come with the hook wrench.
I have calibrated it to zero, but doesn't measure 1" the same as my Brown and Sharpe 1-2".
I am gong to go with the new(old) mic. I'm guessing there's a reason Mitutoyo has the reputation it does.
Thanks to everyone for the input, I appreciate it.
I find that very odd. It's in the nature of threads to work across this range. It might need to hit the trash can or get used as a C-Clamp just for poops and giggles. But check the B&S first. Do you have gauge blocks? Or even just a 1" micrometer standard that prolly came with your B&S?
I have found a mic. or two that doe not measure consistently over their range, not sure why. Think maybe wear of the threads in a high useage area, perhaps having been "snugged" up a bit much and springing the frame, which may show up in faces not being parallel. Otherwise no ideas, if consistent over full range, should need an adjustment only.
Where I used to work we had a calibration guy. He would test everyone's personal tools to see if they were within calibration standards. If not he would either adjust them or tell you to toss them because they failed or were not repairable. He did not like Chinese micrometers. Some were made well and some were not. The people I worked with were not machinists and would some times grossly overtighten the thimble and ruin the screw threads.
I also forgot, if you are comparing mics. or any other measureing equipment, try to make sure every thing is the same tempature. Do not hold the mic. for 1/2 an hour and use a standard that's been sitting in a hot or cold spot. The measurement will change!!
For giggles, take a piece aluminum, 1in. or so, clean up as best possible, measure size a few times, run hot tap water on it for a minute or two, measure again. Should be a larger measurement.
Doing calibration in a nice warm house, then running out to the shop where it's about freezing to measure something that's at the shop tempature does not work either.
Or take a piece of 1/4or so rod, 2ft. or so long, clamp it in a vise uprite, heat one side of it with a hand torch rite above vise jaws. Waves around like grass in the wind when you heat and then let it cool.
For giggles, take a piece aluminum, 1in. or so, clean up as best possible, measure size a few times, run hot tap water on it for a minute or two, measure again. Should be a larger measurement.
Doing calibration in a nice warm house, then running out to the shop where it's about freezing to measure something that's at the shop tempature does not work either.
Or take a piece of 1/4or so rod, 2ft. or so long, clamp it in a vise uprite, heat one side of it with a hand torch rite above vise jaws. Waves around like grass in the wind when you heat and then let it cool.
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