Low Cost Digital Micrometers

[BrianBurns]

Hello All,

I've been shopping for a low cost digital micrometer, and it's not clear from the descriptions whether they will read to tenths of a thousandth or whether they just register half thousandths like digital calipers. Does anybody have experience with the $30 or so quality of digital mikes?

Cheers,

Brian Burns

 

[T Bredehoft]

Welcome to the Forum, Brian. On background, I'm a tool and die maker, retired. On $30.00 digital mikes, They are probably worth their cost, but like the $8.00 digital calipers I bought, not worth using. I'd rather use an old direct reading mike, one that doesn't depend on batteries and was made to be adjusted if needed.

 

[stupoty]

I've had cheep non digital mic's, they havn't done so well. I personally try to keep an eye out for new old stock measuring kit on ebay and stick to bigger brands.

Others may have more positive words on a particular brand though.

Just as a side thought, if they do do tenths you should check them with some gauge blocks to see if they can maintain that across the range.

Mitutoyo make their high end measuring gear in a bunker 10m below ground to reduce environmental fluctuations and cosmic rays(according to their website). I'm guessing the lower end companies don't go to that extreme.

Stuart

 

[stupoty]

Welcome to the Forum, Brian. On background, I'm a tool and die maker, retired. On $30.00 digital mikes, They are probably worth their cost, but like the $8.00 digital calipers I bought, not worth using. I'd rather use an old direct reading mike, one that doesn't depend on batteries and was made to be adjusted if needed.

I've had the (very)cheep digital calipers , they were sooooooo bad.

Stuart

 

[BGHansen]

No experience with cheap ones, I have a couple of Mitutoyo 0-1" digital mics bought off eBay for under $10 each. Frankly, I'd go that route instead of a cheap import unknown. That being said, I agree with Tom above about not needing batteries. My go to mics are Mitutoyo digital ones with the tumbler style read out. I've picked those up for under $30 on eBay. Have a couple of each in the 0-1", 1-2" and 2-3" sizes.

Bruce

 

[BrianBurns]

Hi guys,

Thanks for the replies!

I use a Mitutoyo 6 inch caliper for most things, and like it very much. But---believe it or not---I need to work to tenths when I make the sound-hole rosettes for my traditional Spanish guitars. The errors in the mosaic pattern add up, and the little tiles that come off the end of the log each have to be corrected or they don't march around in a circle of the right diameter. Here is a link (I hope they are permitted) to a photo of the rosette on my website:

http://www.lessonsinlutherie.com/images/DSC001561.jpg

And, yes those are all little pieces of wood, but I never work with anything but glue-ups.

Cheers,

Brian

 

[T Bredehoft]

I never work with anything but glue-ups.

I'm not familiar with the term "glue-ups." Is this in reference to inlays which come glued together and are just inserted in a cavity? Even so, that's great work.

 

[joshua43214]

AvE did a whole series of "Bored of Lame Tool Reviews?" on this subject.
https://www.youtube.com/results?search_query=ave+calipers
Worth checking out, as is his channel. He is some type of engineer, not a machinist, but does some pretty fun and crazy things.

 

[Bob Korves]

Resolution and accuracy are two very different things. Digital mics often have so many digits after the decimal point that it is difficult to keep track of what you are reading. That is resolution, how many digits it READS to. Do not be disillusioned into thinking that is the ACCURACY of the mic. The accuracy is only usually shown in the documentation, not on the mic itself, and is much lower. If you are not working in a clean room with climate control, parts and tools soaked to ambient, tools regularly calibrated, and no touching parts or tools with bare hands, anything beyond .0001" is sheer salesmanship, and while it has some limited value in comparative measurements, it is just window dressing in a H-M shop.

The HF caliper I use every day in the shop has a RESOLUTION of .0005". It's accuracy depends on how and where it is used. Techniques play into the equation. I have no idea what the maximum ACCURACY is, because I don't really use it that way. I am only using it as a modern, $10, easy to read substitute for this:

And it works just fine.

I have no electronic mics. I am not excited about throwing the expensive things away when they fail, and they will fail. Not excited about dead batteries, either. Not at all excited about the bulkiness of electronic mics. If I used mics all day every day, or in a tool room, my preferences might change.

Finally, I am not a fan of AvE, either. Dropped my subscription long ago. I consider it a dog and pony show, playing to the audience but irreverent to all. Entertainment, and I tired of it quickly. YMMV. His ~100,000 subscribers do...

 

[kd4gij]

I have this mic from HF. I had it checked out in the calibration lap where I worked at the time and it checked out fine. We had a military contract and was iso901 certified . it is the same mic sold by Fowler. Also Igaging sales the same mic.
And to answer your question it reads to .00005. The 5th digit is 0 or 5

http://www.harborfreight.com/digital-micrometer-68305.html