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Mitutoyo Digimatic "MyCal" Caliper | |
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CRUFFLER.COM
presents
ACCESSORY
REVIEW,
February
2001:
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Mitutoyo Digimatic "MyCal" Caliper | |
| Crufflers like to measure things. Moreover, we like to measure things with a startling degree of accuracy. It's not enough for us to say that the barrel on a Mauser Gewehr 98 is 29 inches long. No, we have to know, say, and write that the barrel is actually 29.13 inches in length. We habitually measure headspace down |
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Why Calipers?
There are
a couple of types of tools one can use to rapidly and accurately determine
dimensions to within a thousandth of an inch or better. Among these
are the micrometer and the caliper. The micrometer is not frequently
used. Although it is extremely accurate, the micrometer often has
a very limited range over which it can be used - almost always less than
two inches. As a result the caliper is generally the tool of choice
when a device to measure distances of up to six or eight inches is required.
Vernier,
Dial, or Digital
Typically,
calipers are available in three variations: vernier, dial, and digital.
Vernier calipers indicate measurement by means of a sliding scale, not
unlike a slide rule. Dial calipers indicate measurement on a dial
gauge (think of an analog tachometer or speedometer). Digital calipers
indicate the measurement on a digital readout, usually using an integral
LCD display. With respect to expense, vernier calipers are by far
the least expensive, with quality dial and digital calipers running neck
and neck. Digital calipers typically cost a few dollars more than
comparable dial calipers.
The small additional cost of a digital caliper is offset by the versatility and ease of use. Most digital calipers switch between imperial and metric measurements at the touch of a button. And there's no need to learn to "read" a digital caliper - the results of your measurement are immediately read out on the LCD display. Based on ease of use (and our own inherent laziness!), we decided to go with a digital caliper.
Going with
Mitutoyo
Having opted
for a digital caliper, our next step was to determine which brand to purchase.
Some quick initial research narrowed our choices down to five brands, Mitutoyo,
Starrett,
Mahr,
Brown
& Sharpe, and Fowler.
All of the manufacturers made at least one six inch caliper model that
had a resolution of .0005", with an accuracy of .001". All save the
Fowler offered both inside and outside diameter measurement capability.
Several, the Fowler, the Starrett, and the Mahr, offered output to a serial
cable (RS-232) for connection to a PC or other measuring system.
After researching each of the companies, and gauging the various product
capabilities, we decided to go with the Mitutoyo product, as this offered
the best compromise between price and capability. While a serial
output would have been nice, we could think of no realistic use for this
functionality. Prices for six inch calipers from Enco
ran from $94.00 for the Mitutoyo "MyCal" to $131.25 for the Brown &
Sharpe "Digit-Cal Mark IV." We ordered the Mitutoyo. (Mitutoyo,
which, incidentally, is the world's largest metrology company, was founded
in 1934, producing mechanical micrometers.)
Physical
Characteristics
The caliper
arrived a few days later. It was packaged in a fitted plastic box
along with the instructions and the battery. The battery, an SR-44
type available at most consumer electronic stores, was packaged in a sealed
plastic capsule affixed to the instructions. The caliper itself is
nicely executed in stainless steel, with the graduated scale on the front.
The scale also contains the printed circuit that interacts with the readout
on the slide. The slide has a thumbwheel for ease of manipulation,
and a large readout display. There are four buttons around the display:
A power switch, a toggle between zero and absolute measurements, an origin
set, and an inch/millimeter toggle. There is a set screw atop the
slide which may be used to hold it at a given position.
To ready the
caliper for use, open the battery compartment, and seat the battery.
Then depress the power button for a moment. It is unlikely that the
readout will indicate that the closed position is the origin point.
Slide the caliper to the fully closed position and hold the Origin button
down for approximately two seconds. This will set the closed position
as the zero point. At this point, you're ready to measure.
Field Test
The object
of our field test was to determine the caliper's ease of use on various
cruffling related items, as well as the measurement's accuracy and repeatability.
To this end we assembled the following measurement candidates:
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| Round 1 |
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| Round 2 |
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| Round 3 |
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| Round 4 |
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| Round 5 |
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| Round 1 |
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| Round 2 |
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| Round 3 |
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| Round 4 |
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| Round 5 |
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| Round 1 |
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| Round 2 |
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| Round 3 |
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| Round 4 |
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| Round 5 |
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| Round 1 |
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| Round 2 |
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| Round 3 |
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| Round 4 |
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| Round 5 |
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| GO Gauge, Nominal .0640" |
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| NO-GO Gauge, Nominal .0670" |
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| FIELD Gauge, Nominal .0700 |
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Conclusion
Calipers are an important part of
the cruffler's toolkit, and, if one reloads or does any sort of gunsmithing,
indispensible. Our tests and observations indicated that the MyCal
was well calibrated and had an excellent consistency of measurement.
Moreover, the digital readout and controls were intuitive and easy to use.
That alone is an excellent recommendation - too often the application of
technology to a relatively straight forward problem previously solved with
mechanical means results in an overly complex tool that is at best
confusing. By marrying technology and simplicity Mitutoyo has provided
the best of all worlds for the hobbyist, cruffler, or anyone who needs
a highly accurate but easily used measurement tool. And let's not
leave out price; at less than $100.00, the MyCal represents one of the
best values in digital calipers out there. While the Mitutoyo
MyCal isn't the only good digital caliper available, it does represent
one of the best compromises between price, capability, and ease of use.
And now, our
Buy-O-Meter rating for the Mitutoyo MyCal digital caliper:
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