Talk to me about calipers.

after you get calipers, shop for a small piece of O1 precision ground flat stock. thickness and width are usually very tight tolerance, so use a piece to calibrate with. with Starrett brand, the thickness is +/- 0.001 and the width is +.000/.005", so they would make good calibration blocks.
 
after you get calipers, shop for a small piece of O1 precision ground flat stock. thickness and width are usually very tight tolerance, so use a piece to calibrate with. with Starrett brand, the thickness is +/- 0.001 and the width is +.000/.005", so they would make good calibration blocks.

a quality dowel pin also works...they are case hardened, ground to a total spread of .0002. For $2.50 hard to beat. I used 'em years ago for a quick mic check. Eventually I bought gage pins and gage blocks (Jo-blocks to some...)Some of the Chinese gage blocks are very good.

https://www.mcmaster.com/#98381a547/=1cc89i6
 
OK folks - ya'll cost me another $40! I broke down and ordered the Igage set https://www.amazon.com/dp/B00INL0BTS

So far, I think I like them. Interesting they don't have the auto OFF function. Says they are "low battery use" so the average battery will last 2 yrs, about the same as my $100 set of Mitutoyo without turning off much. It's handy to have them always ON when reaching for them. Let's see how the battery life is. They sure do measure good and return to Zero each time.... so far. Only had them a couple of days.

I was initially worried/surprised about the no auto off as well, especially since the rest of the digital measuring tools I have from them DO have this feature, HOWEVER.... I leave them on constantly and I don't think I've changed the battery yet, or if I have, it's only been once. I believe they will last for at least 2 years with "normal" use, I.E., leaving them on sometimes, turning them off others.

Now, my much more expensive SPI calipers seem to need constant battery replacement whether I leave them on or not, though it is a different (smaller) button cell.

Incidentally, I did measure the current draw on the iGaging while on and off. and while on, they draw only 21 uA (micro-Amps), and off only around 1.2uA.

I believe the coin cells they use are rated at about 220mah, so if my math is correct, at 21uA, you're looking at about an 11000 hour battery life, or 1.25 years, give or take, if left on 24/7.

Granted, I was using a relatively cheap multi-meter to take my measurements, but I think the numbers make sense.
 
Shucks, if you to change battery once/yr it's still not bad. Those little CR2032 batteries are less than 50 cents each.

I'll bet the idea was they could make a lower current draw by not having the auto on-off circuit involved.
 
Ken, I think you're right. That auto off feature probably has a little pulse counter as a timer with an interrupt that resets the count whenever the sensor moves on the scale. That little circuit is working non stop.

Manufacturers are getting smarter with circuitry. The first scope I ever bought with an illuminated reticule ate batteries for breakfast. Now you can get red dot optics that run for several years without ever turning them off.
 
Back
Top