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MTNGUN
05-05-2009, 11:02 PM
Recently Horror Fright listed an electronic micrometer for $30 (item #98485).

I never seem to have enough 1" mics -- it's nice to have one at every work station -- so I thought I'd give the HF a try.

Hey, it seems OK. Unlike some Chinese mics, the "feel" is smooth and consistent. I like it.

The plastic piece covering the electronics looks a little flimsy, so you wouldn't want to drop the mic on a concrete floor, but then, you wouldn't want to drop your name brand electronic mic on a concrete floor, either. At least if you drop this one, you're only out $30.

Accuracy is only rated at 0.0001", but that's fine for everyday use.

http://i487.photobucket.com/albums/rr235/mountainmolds/hf_mic.jpg

x39
05-05-2009, 11:55 PM
Accuracy is only rated at 0.0001", but that's fine for everyday use.
You have a mike that measures closer than that?

MTNGUN
05-06-2009, 11:14 AM
Well, I have an electronic Fowler that displays 0.00001". Whether it is really accurate to 0.00001" is subject to debate.

By the way, the HF mic displays to 0.00005" (not visible in my photo). The HF website says the mic is accurate to 0.0001", contradicting the label in the mic case that says "accurate to 0.00005".

To further muddy the waters, the instruction manual says 0.00005" resolution, but 0.00015" indicated error.

I trust the mic to 0.0001", at best.

And by the way, when using this mic, be sure to wear ANSI-approved safety goggles, and keep away from children.

MTNGUN
05-06-2009, 06:31 PM
I used the mic for routine measurement chores today and discovered one thing I don't like -- there is no auto on/off.

Furthermore, the on/off button doubles as the "zero" button. So..... sometimes when you intend to turn the mic off, the mic ends up getting zeroed, instead.

That was very annoying, so I decided to leave the mic on all the time.

If the electronics are similar to the chinese calipers, the on/off button only controls the LCD display, not the "brain". If that's the case, battery life will be about the same even if you leave the mic on all the time.

I'll try it and see how long the battery lasts.

Otherwise, I am happy with the mic's performance. Accuracy and repeatability seem to be fine.

clutch
05-06-2009, 06:39 PM
.50, what are you shooting?

Clutch

John Stevenson
05-06-2009, 06:41 PM
Can it switch between metric and imperial easily ?

I hate auto on / off as everytime you pick the damn thing up it's switched off to save 0.000001 pence worth of battery ?

My time is worth far more than a battery every 3 months

Liger Zero
05-06-2009, 06:45 PM
So they haven't exploded, reversed the polarity of your shop or begun leaking hydrogen sulfide?

Impressive for a Harbor Freight item!

x39
05-06-2009, 07:17 PM
Well, I have an electronic Fowler that displays 0.00001".
Holy cow, I guess I'm behind the times. Does the display flicker on the last digit or is it pretty solid?

juergenwt
05-06-2009, 08:13 PM
0.00001 or 0.000001 is just like using a 1/10000 indicator - it will drive you nuts!
Am I going goofy or what are you guys working to. If I need to be within 1/10000" or 1/1000 mm I would use a Sheffield Gage.

Bill Pace
05-06-2009, 08:35 PM
I got one off ebay and its kinda scary how much it looks like a Mitu:eek:
and like you, Im pretty darn impressed with the thing - think I paid $40+ for mine ....

MTNGUN
05-06-2009, 10:32 PM
Holy cow, I guess I'm behind the times. Does the display flicker on the last digit or is it pretty solid?

The 5th digit on the Fowler is pretty solid if you are measuring something solid. For my purposes -- mostly measuring lead bullets, as shown in the photo -- the 5th digit is meaningless, and I ignore it.

Normal micrometer ratchet force is enough to squash lead slightly and alter the measurement. I'm thrilled to get readings consistent to 0.0002" on lead. If you measure the same spot repeatedly, it will keep getting smaller and smaller because each time you measure it, it gets squashed a little more.

In fact, instead of using the ratchet, I use the big knob and rely on the torque wrench built into my fingers. The "feel" of the mic is critical (and the Fowler's "feel" is a bit stiffer than I like. The HF mic is better in that respect.)

tattoomike68
05-07-2009, 01:19 AM
Thats a nice cheap mic but I dont see the point of measuring a bullet. shove it through a die and size it that way. its not like you will chuck it in a lathe and take .0001" off it if its too big.

Call me a dummy but whats the point of measuring it ? it seems to me you could get a carbide die made and ram the bullets through it by the thousands and #1 would be the same size as #10,000

JCHannum
05-07-2009, 07:06 AM
MTNGUN manufactures bullet molds, and very good ones at that. They are made individually to the customer's specifications. The bullet cast by the mold must be measured and within tolerance.

With that, the best you can expect from any micrometer is a resolution of 0.0001". I would be suspect of an HF mic being capable of producing that level of accuracy. It would be interesting to send one to an independent calibration service.

Bill Pace
05-07-2009, 08:31 AM
It would be interesting to send one to an independent calibration service.

4-5 years ago my son bought one of the cheap ($20) digital calipers to keep in his tool box that would catch a lot of abuse and was pretty impressed with it. Came time to send all the mics, calipers in for check and on a whim sent the cheapo --- came back as the most accurate of the lot:eek: Sent it in for 3 years til it finally got stomped on,- got excellent readings.

ckelloug
05-07-2009, 10:10 AM
I agree with Bill on calipers. I tested a harbor freight caliper on about 100 measurements on NIST traceable Starret gage blocks and found no errors not attributable to human error due to mediocre feel.

If the mics are like the calipers, they're decent but if they're like the calipers others have taken apart and measured current drain on, they draw as much or more current off as on so to worry about turning them off may be irrelevant. I don't have the reference but I believe it was posted as a response to one of Rick Sparber's caliper threads.

JCHannum
05-07-2009, 10:32 AM
Calipers and micrometers are calibrated to very different standards of accuracy. A micrometer with 0.0001" resolution is ten times more accurate than a caliper with only 0.001" resolution. Throw in Abbe error and other sources of inaccuracy inherent in calipers, and what is acceptable for a caliper is not for a micrometer.

The spindle of a micrometer rotates, and the spindle and anvil must be parallel, otherwise measurement will differ as the spindle rotates. This parallelism is measured with optical parallels, and the spindle lapped to correct errors. I question this being done with a low end import.

TGTool
05-07-2009, 11:33 AM
I've just come upon a caliper problem I haven't got to the bottom of yet. I got a Tesa Shop Cal digital a couple or three years ago. I've got Tesa and Etalon mics and like the Swiss feel and quality. In any case, I was having a little trouble fitting a bore which I was measuring with the caliper and comparing to the male part measured with the mic. On a whim, I measured the 3" Tesa micrometer standard with the caliper and it measures at 2.997. WTF? Re-zero the caliper, remeasure the standard and I get the same thing.

I initially trusted the standard as being good, but compared it to the 3" gage block just for good measure and they agree.

I finally attacked the fitting problem by zeroing the calipers on the cylinder that had to fit into the bore so I got a + - relative to correct size but this is bogus. A Swiss digital ought to be better than that. I emailed Tesa's contact us but haven't heard boo from them so my problem with their equipment probably didn't make the grade for any attention from human beings. I have no idea if this is a fixable problem or if it's really that incredibly much off. Perhaps I should also check in metric mode to see if it's a measurement or conversion problem but I don't begin to understand what I'm seeing with this caliper.

ckelloug
05-07-2009, 11:59 AM
JC,

I agree with you. My statement about the mic being alright because the caliper was alright stemmed from my suspicion that they are probably actually using the same production run of calipers and mics in their workshops when they are busy making knockoffs and other products.

It's a weak argument and with what good tools are going for on Evil bay, you could probably get an analog starret for the same money as the HF stuff.

MTNGUN
05-07-2009, 06:54 PM
I was having a little trouble fitting a bore which I was measuring with the caliper

I use calipers for measuring length, and as a layout tool. There are better tools for measuring a bore.

TGTool
05-07-2009, 07:25 PM
I use calipers for measuring length, and as a layout tool. There are better tools for measuring a bore.

Of course it depends on what you're doing and what accuracy you need.

In this case it was a part mounted on a mandrel with a short large inside diameter. Measuring with anything else requires demounting from machine and removing from mandrel so calipers are the best choice for getting the lie of the land. I move to other tools for better accuracy.

sidneyt
05-08-2009, 08:53 PM
I have also recently purchased a HF 98485 electronic digital mic and I am pleased with it. I also own a Mitutoyo digital mic that I purchased used on Ebay a few years ago which although well used is quite a joy to use. The HF is not quite as smooth as the Mitutoyo, but it is certainly good enough for HSM work like I do.

Another excellent deal at HF is the electronic digital indicator
(93295) they have on sale on occasion for $23, but even the regular price of $30 is not bad. I have owned two of these indicators for more than 6 months and they both work flawlessly.

MTNGUN
10-05-2009, 08:37 PM
Update on the HF mic. As I mentioned in the original post, I have been leaving the mic turned on 24/7 because the OFF button also zero's the mic, resulting in a zero when you only intended to turn it off.

The original battery finally died yesterday. The spare battery (included with the mic) was installed and it's back in business. Looks like battery life is 5 months running 24/7, and that's with chinese batteries. I can live with that.

My only complaint is that I dropped the mic on a concrete floor and the movement has never been 100% smooth since then. Some of the range is smooth and some not. The range I normally use is smooth so I continue to use the mic as my daily driver.

In fairness, few electronic mics are guaranteed to survive being dropped on a concrete floor. At least if you drop the HF mic, it's not a great loss.

Black_Moons
10-06-2009, 05:01 AM
I use the cheap 'pasudo' digital micrometers. http://www.drillspot.com/pimages/403/40309_300.jpg
Basicly its just a mechanical digit encoder on it and it displays up to 0.001" on the counter itself, 0.0001" must still be read off the vineer. Its rather nice as I know its not gonna loose zero/etc. Or run outta batteys :)

Only thing I hate about micrometers is how long it takes to go from 0" to 1", when you gotta make a near 1" messurement and your micrometer case only accepts them with the spindle near 0" its really annoying

EVguru
10-06-2009, 05:20 AM
Many of the cheap calipers/micrometers are supplied with LR44 cells, which are Alkali. The longer lasting cells are SR44 and are Silver based.

I think Mitutoyo have got some new micrometers out with a much higher resolution encoder, which means they can use a fast thread for adjustment.

Circlip
10-06-2009, 05:22 AM
Wow, another thread extoling the virtues of Chinese copyology. How long before the backup of "Foreign imports ruining the home manufacturing markets"??

Beware of Gree --- Chinese bearing gifts. :rolleyes:

Regards Ian.

MTNGUN
10-06-2009, 12:57 PM
Wow, another thread extoling the virtues of Chinese copyology. How long before the backup of "Foreign imports ruining the home manufacturing markets"??

Beware of Gree --- Chinese bearing gifts. :rolleyes:

Regards Ian.

Ian, I take it Yorkshire is in the UK? As an American, I consider the UK a foreign country. Should we ban discussion of all UK/European machine tools because they are foreign ? Should our Canadian members only be allowed to discuss machine tools made in Canada ?

I think I understand what you are REALLY trying to say. Tools made by white people good, tools made by non-whites bad. That's the unspoken but obvious rule over at Practical Machinist.

As I have opined on other threads, I believe strongly that there should be protection for American manufacturing. I do favor American products when they are available and when the cost difference is not huge. But even if I wanted to, I could not operate my shop without imports. It shouldn't be that way, but it is.