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MIcroMeter quAlIty And AccurAcy

Product quality and accuracy cannot be valid unless referenced to a quality and accuracy standard.
All Starrett precision measuring tool standards meet or exceed accuracy and performance specifications of national and international standards
and are traceable to the National Institute of Standards and Technology.
The Starrett Company does not rely on statistical sampling inspection. Every precision measuring tool is individually inspected.
All Starrett micrometers have the same accurate heads as outlined in the chart. Inaccuracies because of size can be minimized if the tools are set
accurately to standard, and measurements are carried out in a similar position with similar pressure.

HoW to Adjust stArrett MIcroMeters
Adjustments to Starrett Micro meters are rarely needed; however, if it becomes necessary,
they can be readily adjusted in two easy operations as follows: MicroMeters

Starrett Micrometer Accuracy Standards
(Unless Otherwise Noted on the Catalog Page)
Type Range Readout Accuracy
1" .001" ±.0001"
1" .0001" ±.00005"
Mechanical
25mm 0.01mm ±0.002mm
25mm 0.001mm ±0.002mm
1" .00005" ±.0001"
Electronic
25mm 0.001mm ±0.002mm

1. If any play should develop in the spindle screw 2. After carefully cleaning all dirt or grit from the
threads due to wear of the spindle nut after long measuring faces of anvil and spindle, bring them
use, first back off the thimble, insert the spanner together and insert the spanner wrench in the small
wrench in the slot of the adjusting nut and tighten slot of the sleeve. Then turn the sleeve until the line
just enough to eliminate play. Illustration shows on the sleeve coincides with the zero line on the
how easily this is done. thimble as shown.

MeAsurInG tIps froM our experIence
• Most obvious to everyone is to keep the work to be measured and the micrometer anvil
Key to stArrett MIcroMeter and spindle faces clean.
nuMberInG systeM • For very fine measurements, the micrometer should be set to zero or to a standard by your
Key to Starrett Micrometer Numbering System "feel", by the friction thimble, or by the ratchet, whichever you will be using.
Prefixes • The most popular micrometer option has been the ratchet speeder because it does three
R Reverse Reading things well: it speeds opening and closing, it applies uniform pressure from the ratchet,
S Micrometer Set and it allows for using the thimble for individual "feel".
T .0001" Reading • The speeder is helpful because it takes forty turns to cover the range of a typical English-
V 0.001mm or 0.002mm Reading, as specified reading tool and fifty turns to cover the range of a metric-reading tool.
Suffixes
F Friction Thimble • Large micrometers especially should be set to a standard in the same approximate
L Lock Nut position in which they will be used, that is, vertical or horizontal, to minimize any frame
M Metric flexure influence.
N Non-Rotating • Too much speed in approaching the work will result in an inaccurate measurement.
P Plain • If the micrometer has been set to a flat standard, you can get approximately .0001"
R Ratchet Stop (0.0025mm) difference when measuring over a round because the same pressure is
S Speeder being applied to a point or line contact.
TN Threaded Hub and Check Nut
W/SLC Standard Letter of Certification • Carbide or hardened steel measuring faces are a matter of choice. Carbide wears longer but
X Micro-lapped Carbide Measuring Faces many craftsmen think they get a better "feel" with highly finished steel measuring surfaces.
Z With Case • Insulating pads on micrometers are a matter of personal preference. With the Starrett
ZZ Case Only balanced micrometer design, there is no need for insulation. Insulation from hand heat is
usually more beneficial on long sections, such as end measuring rods.

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