Fractional calipers
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I bought a mechanical, fractional caliper a few months ago as a luxury and am quite surprised how useful I’m finding it to be. My old caliper was a digital decimal caliper and was rarely used. Silly as it sounds, more often than not, the battery was dead. When it ran, it just wasn’t very helpful to have decimal inches.
The new caliper is mechanical and reads in fractions down to 1/64th of an inch. It is on my bench all the time and gets a lot of use. It is a D3208 sold by Grizzly:
http://www.grizzly.com/products/Fractional-Dial-Caliper/D3208?utm_campaign=zPage
Please, please, _PLEASE_ do not turn this into a discussion of metric vs. imperial. But, I’d say that if I were to purchase a metric caliper again, it would most definitely not be electronic. By the way, although this reads in fractions, it also has a decimal (inches) scale.
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You must be logged in to view attached files.Indeed, I have one of those and use it all the time because all my tools are imperial and that’s what I use mostly in woodwork – though I’m used to both systems.
Having said that, they are extremely rare in the UK to the point of being unavailable, though plentiful, I think, in the States.
The complexities of getting a digital caliper to register in multiples of 2, 4, 8, 16, 32 and 64 seems to be beyond solution.
20 October 2016 at 2:36 pm #141694I agree. I’ve had a few digital calipers and they all sucked. They were inaccurate, inconsistent, and used up the batteries when not even in use. I didn’t think much of any of them, though I didn’t have the high-end of the market that cost over $100.
I got my dial caliper used, checked it for accuracy on a gauge block, and it works so much better. You don’t lose but a second in reading the vernier and dial instead of a digital readout.
@delong1974 , good point about accuracy. Most of these things have scales or displays that show more digits than the actual precision or accuracy of the instrument. Even on this one, the fraction scale is shown to three digits, e.g., 0.100, but the real precision is only two digits.
@howardinwales , believe it or not, the old digital caliper *did* have a display that would show fractions of an inch and, if the result could be reduced to a simpler fraction, it did so. So, it would show 1/32 rather than 2/64. Even so, it was useless! The thing thought it could measure to 1/128, so any time the reading did not simply to 64ths, 32nds, etc., you got 128ths. Honestly, I usually don’t even want 32nds. If you grab a reading and see 21/128ths, quick, what’s the closest 16th? Closest 32nd? Or, if you read 19/64ths, same question. It was just too tedious to use. Now look up at the fractional scale in my first picture. Wherever the needle is, just find the nearest 1/8, 1/16, 1/32, or 1/64 and you’re done. You can immediately see whatever precision you want to use and you see it in fractional terms. Okay, all the metric guys are throwing up by now, and I sort of agree, but if you are working with imperial measurements, the visual analog scale is essential because it’s really an analog computer to rounding to a desired precision. Heck, just print it out and stick it on the wall and you’ll find it helpful for converting measurements, no caliper required![attachment file=141697]
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