When using measuring tools, how much force is used to press against the part? - Page 3
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  1. #41
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    This video might be of interest to some. It would have been nice (as in relevant) if he had stated what the price differences are. I know but not sure if all do.

    What I find interesting is the way he holds the calipers and measures with them.


    Quote Originally Posted by The real Leigh View Post
    Note the large mics piled up in the background at lower right.

    This guy is certainly an exert on precision measurement.

    Def of "expert": A drip under pressure.

    - Leigh
    When I started to watch the video I had no idea where the guy was going to take as long as he did. Good quality calipers are better than cheap ones. Who'd have guessed?

    I don't regard the guy as an expert but what he did and how he did it looked OK for a guy in the environment he was in.
    As said, if he mentioned the price for a Mitutoyo it would have helped as he didn't really IMO ridicule the cheap ones. Just showed they weren't as good.

    To me it just looked as if he took better care of some tools more than others.

  2. #42
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    When trying to use my calipers to read as accurately as they can (oxymoron aside) I only hold the caliper by the jaws (Part, jaw, finger). I don't use my thumb to move the slider.

    Using this method there's no way to bend the bar of the caliper within reason.

    {spam deleted - TRL}
    Last edited by The real Leigh; 08-24-2017 at 04:23 PM.

  3. #43
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    Quote Originally Posted by BobM3 View Post
    Use gauge blocks and ring gauges to "calibrate" your feel.
    Flat surfaces, cylindrical surfaces, and spherical surfaces will all have a different feel. It also varies with the diameter of the part. Ideally one would use a standard that matches the shape of the work. Look up Hertzian stress

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    I just squeeze until I get the right number...if I can't squeeze enough I'll usually take the part to the belt sander.

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    You're using way too much force if you're concerned about "bending the tool. Practice on a gauge block.

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    Quote Originally Posted by TDegenhart View Post
    I recall many years ago(~40) Starrett had a high precision c-frame mike that would set to a calibrated force. The thimble was huge. I don't know what the part number was and have not seen one since. Perhaps some of OF's will recall this.

    Tom
    Starrett 221

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    Don't expect "high" accuracy with calipers. If you want tenths use a mike.

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    Quote Originally Posted by halfmoonbear View Post
    Don't expect "high" accuracy with calipers. If you want tenths use a mike.
    You'd be surprised (and disappointed...) at the number of engineers, QC people, and other folks that should know better that think this is a reasonable expectation for a caliper.

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    Quote Originally Posted by Danny VanVoorn View Post
    I worked with a fellow that used to get stuck re-single pointing precision aircraft threads that were rejected by inspection, all he had to go by when setting it up was looking at the light coming through on both sides of the tool. Some of those parts were for fighter jet landing gear and extremely expensive and there wasn't much excess material so no room for error.
    ITW had a separate room for grinding fine pitch hobs. It was dark as the ace of spades in there, everyone was grinding away with a little light behind the wheel, centering it in the space similar to what you just described. Those were class A hobs ...

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    Quote Originally Posted by halfmoonbear View Post
    Don't expect "high" accuracy with calipers. If you want tenths use a mike.
    The most widely used caliper manufacturing and accuracy standard is DIN 862 and can also be found as an ISO standard. In all measuring equipment brochures and catalogues (including Mitutoyo) I've seen with calipers the reference stated is DIN 862 - when a standard ir referenced.

    Each type (vernier, dial and digital) have their own accuracy specifications.

    Vernier are the least accurate.

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    You know why micrometer thimbles are knurled, right? It's so the pipe wrench can get a better grip.

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    Quote Originally Posted by John Garner View Post
    You know why micrometer thimbles are knurled, right? It's so the pipe wrench can get a better grip.
    I was taught this when I first started...works great, vise grips work well too!

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    Quote Originally Posted by greif1 View Post
    If you press on the jaws of a caliper, directly in line with the workpiece, no bending is possible and the results will be very repeatable. The zero should be set the same way.
    For me, this is the best answer so far...
    Following this practice repeatable readings are routine.

    And cleanliness is ABSOLUTELY necessary: frequently, I find the zero on my Mitutoyo Series 500 Caliper reading 0.0005" but it is just a dust speckle, not visible but registering on the polished surfaces of the jaws. Many false readings (and perceived lack of precision of digital calipers too) are from lack of cleaning when measuring.

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    Still say check the friction or hand feel to a good Jo block and if not getting the same as the Jo then find another vocation..

    17 year old grand son was getting .0002 with my old Etalon 230 one inch micrometer after about 10 minuets or less.

    Along with five other Boy Scouts.. all getting it .0002....

    Normally I each knots..

    Still for gauge work or .0002 spec I use a plate check or dial mics..likely I would never send a close (,0002 or better with a feel check...just too much chance the customer inspector would not have a good feel.
    Last edited by michiganbuck; 08-28-2017 at 12:01 PM.

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  20. #55
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    Quote Originally Posted by John Garner View Post
    You know why micrometer thimbles are knurled, right? It's so the pipe wrench can get a better grip.
    Cant prove it but I think you are telling me porkies.
    Not too sure about your mate Plastikdreams either.

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    Quote Originally Posted by camscan View Post
    Cant prove it but I think you are telling me porkies.
    Not too sure about your mate Plastikdreams either.
    You don't need a pipe wrench when simple vise grips, channel locks and even pliers will do to tighten micrometers. Yeach! Don't you know pipe wrenches are only to be used for whacking center punches.

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    Quote Originally Posted by michiganbuck View Post
    You don't need a pipe wrench when simple vise grips, channel locks and even pliers will do to tighten micrometers. Yeach! Don't you know pipe wrenches are only to be used for whacking center punches.
    Blimey, you learn something new every day. I will have to ask the old man for a rise. Thanks fellas,if I get a rise the beers are on me.

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    Oil rig roughneck goes to the tool crib.

    I need a real big wrench..
    What size?
    Don't matter just big..
    Won't work if it is the wrong size.
    Size don't matter, just big because Im needing it for a Hammer.

  24. #59
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    Surprising what can be seen if " Caliper measurement pressure " is Googled.
    Caliper measurement pressure - Google-sogning

    Be sure you're sitting down if you look at the prices for these Mitutoyo.
    MEASURING INSTRUMENTS CATALOG No.E216
    Last edited by Gordon B. Clarke; 08-29-2017 at 05:31 AM.


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