Electronic Caliper


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MaterDei
October 12, 2003, 10:11 PM
Is an electronic caliper a good idea. If so, how about this one?

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=47256

I know the old saying, "if it seems too good to be true, it probably is".

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444
October 12, 2003, 11:01 PM
I do not have much respect for stuff sold by Harbor Freight. I have purchased various items from them in the past because the price was right and there is a store local to me. I have always been disappointed.
I purchased an inch pound torque wrench from them on-line and I can't get it to click off when I reach the set torque. I bought it to precisely tighten the fasteners on scope mounts and rings. I called Leupold to get the correct values, set my wrench to that setting and tightened. I said to myself, this seems awfully tight, just before the screw head let go.

On a semi-related note, when I became a firefighter I purchased some hand tools from them to carry on the job. Pliers, cresent wrench, sheet metal punch etc. Most of them failed on their first use.

The stuff they sell is basically the same thing you would get at a low budget flea market.

A digital caliper is by definition a precision instrument. It only makes common sense that you can't get precision instruments cheap. There are a number of digital calipers offered by reputable companies that sell reloading equipment along with companies that sell good quality tools. I feel you would be better off buying a good one rather than wasting your money on this one.

P95Carry
October 12, 2003, 11:15 PM
444 is about right ... but .....

If you accept that pretty much you ''get's what yer pays for'' ... you can still find this adequate.

If the tolerance of accuracy is +/- 0.0005 and some cheaper ones can be this good . it'll do well. I think there is some luck involved cos i got a semi-cheapie from harbor freight ... just for reload bench (have two other high grade analogs) ... and find it very adequate for OAL and dia etc.

Be prepared to take a gamble.

HSMITH
October 13, 2003, 12:04 AM
If you are going to buy a digital caliper buy a Mitutoyo. A 6" will run you about $80 and they are probably the best made. The battery in my old one is over 6 years old and still going, used probably an hour a week and left on for a day or two at least once a month. It is still within .0005" on EVERY test I can think of with calibrated standards.

Remember, on things like this you can buy a good one this time, or you can buy it next time, or even the time after that. It is a LOT cheaper to do it right the first time.

C.R.Sam
October 13, 2003, 12:06 AM
Something to ponder...
Digital measuring instruments usually display high resolution.
Which has NO bearing on accuracy.
They should be calibrated often.

Before every use when doin real critical measurments.

Same goes for "clicker" torque wrenches. In some occupations, the "clicker" wrenches are to be calibration checked every time they are checked out of the tool room.

Sam

P95Carry
October 13, 2003, 12:22 AM
Good points there .. re calibration ... forgot to mention that.

Keep a piece of good gauge rod handy and calibrate every time if critical measurements needed.

clown714
October 13, 2003, 12:35 PM
i'll second the mitutoyo.

very pleased w\mine

clown

ocabj
October 13, 2003, 01:34 PM
I paid $60 for a used Mitutoyo dial caliper with .1/revolution on the dial off of eBay. Mitutoyos are expensive, but worth it.

WhoKnowsWho
October 13, 2003, 01:35 PM
I got the normal dial caliper from them so I wouldn't have to deal with calibration. It's not as annoying to read the dial as I expected, so I have no problem with it. It works fine for the 3 decimal places needed in reloading.

If you really have that much of a problem with it, return it. I bought two different benches to try and load on them and returned both without a hassle.

Intune
October 13, 2003, 01:41 PM
I got mine on ebay, can't remember the manufact but I checked their site for retail $ before I bid. Got mine for a song. Long song but a song nonetheless!

gobabygo
October 13, 2003, 07:56 PM
I bought that caliper from Harbor Freight and it's crap. DON'T BUY IT!

Mine may or may not be the exception, but... on mine if I leave it on for a while it "freezes" and I have to take the battery out for a while to get it "unstuck". It also frequently looses it's "zero" and starts adding odd numbers and I have to rezero it. It's just awful.

I bought a pair of dial calipers and after using this, I discovered 2 things. First, digital calipers are only easier to use than dial calipers in that they are easier to slide. Not really a big deal. Reading them both is very very easy. The second thing I learned is that the Harbor Freight calipers, when it was working, was accurate.

Oh, and in case I didn't get my point across... DON'T BUY IT! :p

JA
October 13, 2003, 08:02 PM
I have a 6" digital one I bought from Midway several years ago that is the same model as the one sold by HF. I have used the crap out of it and it still gives the same reading as my Starret micrometer does.

Clark
October 13, 2003, 09:04 PM
I was real happy with the $20 Chineese cheapee dial caliper from Midway, when someone I know designed a digital caliper. I had to go buy one so we would have that in common. I really like the zero feature, it saves me from doing subtraction in my head.

Feral_Goz
October 14, 2003, 12:23 AM
I bought the best one I could afford from an electronics supply store. It was AUD$79.95. After struggling to open the bolt on my .303 with a too long case inside (almost had to resort to a 2X4). I decided I had to have a decent and accurate caliper. It goes to .0005 and does the job for me.
No more stuck bolts.

Feral_Goz

KC
October 14, 2003, 12:42 AM
Back when it was really cool and unusual to have one, I shelled out $500 for a 12" Mitutoyo digital caliper. One of the absolute best measuring tools I've purchased. (They don't cost that much any more, of course.) In any event, I would suggest that if you go digital, to get an 8" and not a 6"--it will have a lot more usefulness overall, and doen't cost that much more. One of the especially nifty things about digital equipment (at least from Mitutoyo) is that they will work in both Standard and Metric, and will convert values back and forth between systems at the push of a button.

In looking at mechanical calipers, get a pair that measures only 0.100 per revolution, not 0.200 per rev. It's much easier to read, and generally more accruate.

Check the ads in the newspapers. At least once every couple of weeks there will be an ad from Mrs. Machinist selling off the departed Mr. Machinist's workshop. Pawnshops may also be an acceptable source.


When buying used calipers, mechanical or electronic, there are a couple things to remember:

--there should always be a brand name on the instrument..."Central Machinery" does not count.
--the jaws, inside and outside, should grip a piece of paper equally along their length. If they grab more tightly at one point, or you can see daylight between them when the jaws are closed, don't buy them.
--all the edges on the measuring surfaces-- inside, outside, depth-- should have a definate edge. Not so much that you can cut paper or your hands, but not so much that you think "this is a nicely broken edge".
--invest in the $1 or so that a pin gauge of .2500" in diameter costs, or a 1.000" calibrating standard costs. It's worth the small amount of money they cost when buying used equipment.

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