Page 77 - TesaKatalogen

I n t e r n a l Me a s u r e m e n t

THE CHALLENGES OF INTERNAL MEASUREMENT

Bore measurement is more difficult than external measurement of components. Apart
from the very tight tolerances specificied, all measuring elements having a direct influence
on the uncertainty of measurement must be designed in such a way that they can fit into the
bore to be checked.

3-Line contact offers a The three measuring bolts The measuring bolts with 3-line contact allows the micro-
true advantage are spaced 120° apart, meter to align itself parallel to the contact surfaces.
The near perfect auto-centering thus providing optimum
and auto alignment provided by self-centring.
TESA IMICRO, TESA TRI-O-BOR,
ALESOMETER and ETALON INTA-
LOMETER make bore measure-
ment reliable, without the need
for an operator to estimate.

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2-point contact measuring instruments are not self- 2-point contact does not
centring. To enable bore measurements, the use of auxilia- permit the tool to align
ry means are required. itself in relation to the
bore axis.
A single tool can replace
hundreds of plug gauges
Unlike plug gauges that check only
one toleranced size, a single tool
can measure many diameters. De-
pending on the model that is being
used, through holes and blind bores
along with short centring shoulders
can be inspected reliably.

Establishing form errors Dmax. Dmin.
Form errors are established
through measurements taken at
several points within a bore. Micro-
meters with 3-line contact deter-
mine run-out errors in a triangular
way. Micrometers with 2-point
contact measure medium-size
diameters only. They do not allow
users to see what makes diame-
ters measured at various points
different.

D-2