Cheapest metric micrometer on Amazon - Review & micrometer lapping

These metric 25mm - 50mm micrometers are sold on Amazon and eBay. I bought one to see if it would be accurate for my purposes. I ended up having to lap it and then discovered that it had other issues.
Tom Lipton's micrometer lapping video - • Space Micrometer Anvil...
Here are some links to the micrometer,tools I used to lap it, and others that I recommend.
Micrometer (I do not recommend but if you want to see the ad, the same pictures are used on eBay) - amzn.to/2UI4YUp
Norton sharpening stone - amzn.to/39u3JNY
Japanese wet stone - amzn.to/3dDjBkE
Zoom Spout Machine oil - amzn.to/2wBJq45
Good cheap digital calipers - amzn.to/2IDBNg7
The previous links are affiliate links, as an Amazon Associate I earn from qualifying purchases.

[@etow8034]

Most people wouldn't know what an optical flat even is, but you can even see the fringe lines without it even.

[@theeddies]

Yeah you know the QC is bad when you can see that it is out of tolerance without measuring it, lol.

[@leonordin3052]

I bought a micrometer 25mm for 7 dollars in spain, a chinese items store. Works wonderfull no backlash I picked the one that had an ugly oil stain on the package and that closed up to zero on the spot with good straightness. it seemed to be made right after the chinese calibrated their machines so I got really lucky.

[@Daniel-vq9zb]

If the standard was .017 IN under size that was good enough reason to chunk the entire thing in the trash to begin with, if they missed that by a mile I'd assume the quality would continue throughout.

[@theeddies]

Good point. I could have saved myself a few hours but I learned something so not total loss. Thanks for watching.

[@cyril.engineering]

Out of morbid curiosity I bought a few imperial of the same mechanism for dirt. I benched each one. Aside from the ones that were obviously busted, each "working" micrometer gained exactly a tenth over an inch. I used a calculator and some standards, the error is linear enough that you can practically be "dead nuts" by just including it in the result.

[@theeddies]

So take a measurement, make calculation for logarithmic error, and then add to measurement. Double check with a statistical standard deviation formula. And then I am pretty sure within a margin of error that I have 1/2" round stock. Sounds like how the Russians build rockets and they sometimes work. 😁

[@cyril.engineering]

@@theeddiesHaha... Luckily for me, it seems like the gross error was just linear. I only tested 8 points per. It got tiresome because I overlapped the mics onto my "standards" to also ensure each was calibrated to the prior micrometer. I admit I use Insize toolroom blocks on an Insize toolroom plate - there may be a Chinese conspiracy afoot

[@theeddies]

@@cyril.engineering That does sound tiresome. I admire your commitment though. Did you handle the blocks or touch the plate with your bare hands because body temperature can throw those Chinese plates off by a thou or more. Seriously though it sounds like you are the same as me when it comes to measuring sickness and wanting to save money.

[@cyril.engineering]

I tried to keep my hands free. The only things I may have handled for too long were the micrometers. I did use a "standard" that I use with my b&s 0-1 and it reads identically with linear error considered. I did also clean any surface with my fingers before measuring. I think it's worth testing more, but I think for now I'm not really sure of a better benchmark for my equipment. I'm open to ideas, the can of worms is open

[@theeddies]

@@cyril.engineering If you have a set of gage blocks or pins you could measure the error at different lengths. I have a B grade set and an A grade A 1" Mitutoyo gage block that I use for testing and as standards. For my purposes that is more than good enough. Brown and Sharpe make a mic checking kit that has some optical flats glass and gage blocks but it is $$$$. A decent gage block set can be found on ebay for less than $100. I got a used Phase 3 set for $40 shipped but it was one of those really good deals that do not come up much. Like I said it is Grade B but also had some replacement pieces that were Grade A.

[@CalPil0t]

You probably already found a suitable replacement, but I just noticed (17 Jul 22) that Amazon has the Starrett 436.1 MXRL at about half price of 104.69. Contacts are carbide tipped. Ordering one now. I bought the 0-25mm quite some time ago on a similar sale, and although I don't do much metric, this will be handy.

[@theeddies]

I ended up buying a lightly used Mitutoyo with carbide tips for $40 on ebay. It had the original box, standard and wrench.

[@user-oj2rz2wu4x]

السيد الفاضل السلام عليكم ارجو الاجابة على سؤالى انا اشريت ميكروميتر مدى القياس 25 to 50هل استطيع قياس سمك اسلاك المواتير به

[@theeddies]

Yes

[@RickyLee53]

Did you check the standard with something other than veneers?

[@theeddies]

Yes, I checked it with another micrometer as well. In this case, however, it really did not matter what the standard was as the micrometer was not reading consistently.

[@chrisbaca374]

the thimble that the threads go on has a adjust screw on the end. simple fix. should take up that (backlash) i fix those all the time. thanks. precision instrument repair

[@theeddies]

Not doubting what you know, but I am pretty sure I took the ratchet thimble off this one and the screw just held it on. I could certainly be wrong though. Next time I will check that out. Are you in Atlanta? There is a PIR here I think. Best!

[@MF175mp]

I bought the cheapest ones on aliexpress, one of the four in the set has this problem and the lock would move the reading so they would never pass any calibration without a complete redoing. They are equipped with carbide anvils however, and the screw pitch itself is accurate enough. I´m going to lap all of them and clean them up to be the general purpose mikes for normal work which they are accurate enough for but not quite comfortable to trust by caliper measurements.

[@theeddies]

If you get a decent one it is quite a bargain. Especially for non-critical stuff. I was not expecting Starter precision but my cheap digital calipers were more repeatable than this one. It went back and I found a nice used Mitutoyo that is perfect but was 2.5x the price. What are you going to use to lap the carbide?

[@MF175mp]

@@theeddies I have a set of diamond pastes of various grits, also the ugliest one I'm gonna hone to a rough shape with a knife hone first. I'll probably get the optical parallels if my better quality mikes (0,001mm mitutoyo etc.) that I've ordered out of ebay happen to need any treatment. I would also machine a fixture to be able to lap both anvils well even from the larger ones.

[@MF175mp]

Not that I do work in the micron range, I just bought a chinesium readout scale for my lathe's z-axis that reads in half microns which makes the resolution one micron of diameter, I want to see if it's a total scam or is it capable to finish diameters well under 0,01mm. The lathe is a heavy mori seiki, it shouldn't have an issue by itself with extremely precise work.

[@MF175mp]

Of course manufacturers like Sony have put out hundredth of a micron resolution scales but IDK what they're needed for and how accurate they actually would be. I was almost buying one with that resolution off ebay but I noticed from the service manual of my Sony readout that it didn't fit my unit. The price would've been under 100 doll hairs.

[@theeddies]

@@MF175mp My cheap DRO scales read more accurate than my lathe cuts I think. But I have no trouble getting in the .002 range with them. Getting down to 1/2 a thou or under is something I rarely try to do. At that level I break out the emery paper and mics.

[@ValiRossi]

Throw it under that train that just went by. :)

[@johnstrange6799]

Maybe the review will help someone save a bit of time, money and aggravation.

[@theeddies]

At least they would know what to expect. I was not expecting it to be perfect, no cheap tool is, but workable. Wish I would have seen my video first 😄

[@johnstrange6799]

@@theeddies I wish I would have seen your video before I saw your video. lol

[@theeddies]

I am not sure how to take that, were you the down vote again?

[@johnstrange6799]

@@theeddies lol no, but that makes me laugh.