Caliper / micrometer input

L

Larry Frankenstein

Well-known member
I need to replace a caliper / micrometer that I no longer possess. I would appreciate any input on best brands / models or features / specs and any other input you can offer. Referral to a site that has a review of various units would be helpful too – I googled but haven’t come up with much.

I am leaning toward a digital and plan to buy a good used one(es) to save some cash.

Thank you,
Larry
 
It might help if you describe what you plan to use it for..

I have a Mitutoyo digital 6" slide caliper that's great for general fab work, but I wouldn't mic an engine with it.

Then again, they sell a chinese knockoff copy of the same tool at Harbor Freight for $9.99 that I could use for the exact same thing and say the same for results.

If I were mic-ing a crankshaft or pistons or something, I would be buying much better gauges. Generally I leave that up to a pro simply because of the cost of the tools, parts, and my lack of patience to measure close enough to get all of that right the first time. (because it costs a LOT more to build two engines than it does to pay someone else to build it right the first time!)
 
Mice and calipers brands are like the ford Chevy argument.


I wouldn't buy the Chinese stuff. It's cheap but most of them suck.

Watch eBay for a mitutoyo or brown and sharpe eBay ones are good and usually go cheap
 
I've got a Harbor Freight digital Caliper that I've had bouncing around in my tool box for a couple of years and it still works fine. Nice to have and seems to be accurate to .001 and I don't care if it gets lost, stolen or broken. I test it against my Mitutoyo mic every once in a while it is always right on. I would not use it for serious machine work but it comes in handy.
 
MSC Industrial Supply sells some middle of the road made-in-China or Taiwan calipers and mics that are step up from the Harbor Freight stuff, but don't cost as much as the top of the line instruments. I've also got a few Starrett mics and a Mitutoyo caliper, and I get the same measurements either way.
 
I am the son of a machinist and I own Starrett micrometers. Superb quality!

Go on eBay and find them used. Be selective on what you are buying and you can get some great deals on near new equipment at pennies to the dollar.
 
I have 30 year old Starretts that are still as accurate as new. Best digital calipers I have found are the Mitutoyo and the added bonus is they act as a metric converter with the push of a button with no re-zero. MSC is cheapest for new ones most times.

Machinist and tool and die maker since before child labor laws. :D
 
I will agree that digital is a good idea to avoid errors in reading the old-style "turn of the barrel- add this to that.." style. Get one that shuts off automatically after a while. The battery seems to last for years for me. Dual inch/metric is also great to have. After that, how much accurracy do you need? How much do you want to spend? Joel
 
Heh.. my Mitutoyo is still on the same battery it came with about 10 years ago. I leave it on all the time for weeks or months at a time.
 
Thank y’all for the input. To answer Matt93SE’s question re my intended usage, he kind of answered it too:
Matt93SE":3p6hrrz1 said:
If I were mic-ing a crankshaft or pistons or something, I would be buying much better gauges. Generally I leave that up to a pro simply because of the cost of the tools, parts, and my lack of patience to measure close enough to get all of that right the first time. (because it costs a LOT more to build two engines than it does to pay someone else to build it right the first time!)
Click to expand...
But there is always the possibility I will need to measure something (crankshaft or something I am not even considering right now) with a fairly high degree of accuracy.

Re how much I want to spend – the 9.99 Harbor Freight deals ounds great as long as it isn’t a pos in the long run.

I will want one with inch and metric readout, and the auto shutoff sounds like a good idea for me J I had not thought of that.

Thank you,
Larry
 
At risk of stating the obvious you DON'T want to try setting crank bearing clearances using a $9.99 Harbor Freight calipers. They're probably fine for non-critical work though, not sure if they'll be working in 5-10 years.

I do what a lot of people do, use a pair of calipers for all around use and another set of far more accurate inside and outside mics for critical engine work. You can get really good deals on eBay, I just bought a set of German vernier calipers for around $15 and Japanese dial calipers for around $20.

German, Swiss, UK, US, Japanese is almost all good. Chinese runs the gamut from junk to medium, I'd be 99.9% sure that better grade Chinese is OK for daily non critical use.
 
My HF caliper cost around $15 on sale as I remember. It does do inches and metric, I think even the $10 reads in both. Again In would not use it for anything the measurement is critical, but it seems to work for 90% of the things I do.
 
Worth adding , when measuring, for example, a crank journal where it comes down to the tenths of a thousands of a inch, it's a skill, not just something you pick up the mic and do it for the first time, it takes lots of practice to get good at it. It's all about duplicating the feel of the mic when zeroed and on the standard, it takes alot of practice to develop the skill. Call me old fashion, but I still like and prefer the manual mics, someone gave me a digital Starrett, and I've never used it much.
 
I strongly agree with Hap on this one but would like to add a bit.

Dial calipers, regardless if you bought Brown and Sharpe or Mititoyu or Harbor Freight, are the WRONG tool for anything where tenths matter like a crank journal. To prove it to yourself rock the caliper arm with respect to the long axis of the caliper. No matter what you pay there is clearance which will show up as an error depending on how you use them. They also suffer from the feel issue that Hap has discussed and there really is no way around that other than a clutch on the mic. And I don't care if your calipers acutally read tenths (I've never seen one but I'm guessing someone makes one somewhere) or 0.5 tenths......I still stand by my comments.

As far as micrometer quality is concerned, assuming you use a known accurate standard and the mic "feel" properly, I wouldn't get too worked up about brand....it's just a super low lash screw thread with all lash biased in the same direction. Sure I have some premium and 1 crappy crappy mic and I do prefer the top end feel....but I doubt there is much difference in accuracy.

I'd rather have one source of error instead of 2 when it comes to vertical bearing clearances or spun bearings. At the risk of being shot with flak, this is an issue that NO competent machinist would dare argue. Fire away!
 
I doubt anyone with any experience will disagree with you Jay, re the use of a proper micrometer for critical use.

I don't know for sure but would be willing to bet that there are some super cheap Chinese micrometers that do have some significant errors "midrange" where they are harder to check. If not somebody is missing something, it would be about the first product category for which there ISN'T a so-cheap-it-doesn't-actually-work Chinese model.

Not to say that there aren't good Chinese measuring tools, just that I'd be shocked if there are no bad ones.

Al Seim
 
Lots of good input. I do not consider myself a machinist and save those types of measuring jobs (and some $$) for people who are. But when I do what I do (tinker?) I like to be very accurate when I measure items.

Thank you for all the input.

L
 
I've mentioned this before, and Hap referred to it above. Developing acceptable gages includes "Repeatedly and Reproducibility" studies.

Each operator must be able to repeat a reading 3-5 times, and every operator must be able to reproduce the same results. Difficult to do with the best of equipment, and requires experience and "feel" with micrometers.

Then there's the matter of calibration to the appropriate National Standard.

I worked with a Modelmaker whose micrometer readings were ALWAYS .0007" greater than mine, suggesting we each had repeatability, but calibration was warranted.

Unless your working in the "Trades", rely on those who are.

To the original question; calipers only good to .001", and micrometers required to work in .0001".
I always used Starrett or Browne & Sharpe, but I know Mitutoyo makes quality equipment. Most dial indicators only good at .001"; few repeat at .0001". Interapid dial indicators are very good. I would not use anything less.

Avoid older "open rack "calipers.

RJS
 
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