Foo - Those mitutoyo calipers

Those Mitutoyo 'absolute' coolant proof calipers are top notch in the quality department. My boss inspected them today, after 15 minutes he came to me and said these are the best that any caliper could be, and it was almost scary how dead accurate they were. I decided to try taking ID measurements on two ID gages. One was .70000", one was .49990". To make sure I was not fiddling with the calipers so it would display .7000" (which is something I would have to do with my Chinese generic digital calipers), I closed my eyes. I opened them, it was right on. No fiddling necessary. Even the .49990" one, it displayed .4995". It displays in increments of .0005" anyways. The fact that it noticed even that .0001" difference is impressive. Highly recommended.

do you want to get rid of your cheapy chinese digital ones? if yes, pm me.

Hey Boston, if you're looking for a cheapy set of Chinese calipers, here you go (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47257)

Believe it or not, they actually work pretty decently, and haven't died on me yet...

Those Mitutoyo 'absolute' coolant proof calipers are top notch in the quality department. My boss inspected them today, after 15 minutes he came to me and said these are the best that any caliper could be, and it was almost scary how dead accurate they were. I decided to try taking ID measurements on two ID gages. One was .70000", one was .49990". To make sure I was not fiddling with the calipers so it would display .7000" (which is something I would have to do with my Chinese generic digital calipers), I closed my eyes. I opened them, it was right on. No fiddling necessary. Even the .49990" one, it displayed .4995". It displays in increments of .0005" anyways. The fact that it noticed even that .0001" difference is impressive. Highly recommended.

There's no skipping either. Try yanking that thing open and close as fast as you can. It tracks dead solid at any speed. I've been using mine for close to 3 straight years now, in the shop and at my desk. I usually throw it into my tool bag with the rest of my tools when I need to go upstairs to the shop to work on things, it's never been babied one day in its life and to this day, it still works 100%. I like it so much I have a pair at home too.

Here is the one I've been using for almost 2 years:
http://cgi.ebay.com/6-DIGITAL-ELECTRONIC-CALIPER-LCD-DISPLAY-BATTERY_W0QQitemZ110070158985QQihZ001QQcategoryZ25269QQrdZ1QQcmdZViewItem

Not even 20 bucks, and the quality is good for the price. I don't recommend it if you you need to make measurements down to .02mm though. There is too much uncertainty with them, the # always changes.

So...was the extra button to switch from English to Metric?

The gray button is english/metric and the blue button is to set origin, which should only be used once normally since it's an absolute caliper.

I find myself frequently resetting the origin with calipers, for various odd jobs. The other button indeed was to toggle metric/inch. Oddly enough, my Chinese calipers come with the SPC output, while these do not. I don't really care, I've never used that and probably never will.

They can't "skip". They read the capacitance from the read bar which contains copper embedded in the measure rule. So what the head reads is relative to it's position on the bar without any mechanical connection(other than to connect the head to the bar). But there is no wheel or mechanical input into the reading. That is what makes them digital calipers. A wheel would make them analog calipers then I guess.

Actually, technically, reading capacitance would be an analog process, but it's converted to digital for presentation. Interesting, I didn't know capacitance could be resolved that finely.

I thought most digital calipers worked by reading off tick marks engraved in the track or the wheel with an encoder, which is a discrete process. Obviously it can skip if you pass subsequent tick marks faster than the detector's response time.

Actually, technically, reading capacitance would be an analog process, but it's converted to digital for presentation. Interesting, I didn't know capacitance could be resolved that finely.

I thought most digital calipers worked by reading off tick marks engraved in the track or the wheel with an encoder, which is a discrete process. Obviously it can skip if you pass subsequent tick marks faster than the detector's response time.

Yeah, maybe. I guess it's how you look at it. The fact that there are no mechanical moving parts in the read head and that it solely uses digital electronics would make it a digital unit. The display being a digital readout doesn't necessarily make something a digital device though, or lack of, an analog device. I'm not sure if the fact that it reads capacitance makes it analog though. A lot of digital chip takes analog signals and convert them to digital like reading capacitance, but that doesn't make it an analog chip. Like you said, it takes the capacitance and converts it to digital. That in itself makes it a digital device I think. Anyway, no argument here, just a matter of specific terminology I guess. Still neat though.

I always thought it was inductance.

I always thought it was inductance.


Current Mitutoyo calipers use capacitance. Not sure about all the other brands though. In the very near future though, some, or all mitutoyo may be changing to inductive readings.
I know it seems like I have a strangely unnatural love of caliper functionality but I've been doing research into calipers and linear encoders for work recently. I was talking to a rep from proscale(makers of mitutoyo) and that is what he told me. Soon they will be switching to inductance. Not sure why though or how it's implemented.

Oh crap, I wasn't supposed to reveal that little secret... *takes apart and eats prototype*


Current Mitutoyo calipers use capacitance. Not sure about all the other brands though. In the very near future though, some, or all mitutoyo may be changing to inductive readings.
I know it seems like I have a strangely unnatural love of caliper functionality but I've been doing research into calipers and linear encoders for work recently. I was talking to a rep from proscale(makers of mitutoyo) and that is what he told me. Soon they will be switching to inductance. Not sure why though or how it's implemented.

*takes apart and eats prototype*

lol
You're gonna regret that in the morning.

In my view, the fact that the value is continuously variable if you're measuring capacitance or inductance like that makes it analog. Of course, electronics can only interpret that as a digital value...

On the other hand, if it's reading tick marks off, you get discrete values (1, 2, 3, ... , n tick marks).

I'm going to have to dig around and see if can come up with how these things work. You guys have got me extremely curious. I imagine it's similar to how LVDT's work, so the answer is probably out there somewhere.