23
The above method is called a “2-point method”. The other one is “2-chord method”
for electrical measurement and the principle is shown as Fig.14 (see the right scheme):
Measure any two chord L
1
L
2
near the diameter. The distance (H) between the two
chords can be read from the transversal handwheel for worktable.
Measuring steps for 2-chord method
a
According to the LED indication, collect two points (a
1
a
2
) at two ends of
“chord 1” ;
b
Make the transversal handwheel move a distance (H );
c
According to the LED indication, collect two points (a
3
a
4
) at two ends of
“chord 2”;
d
Calculate
L
1
=
a
2
a
1
L
2
=
a
4
a
3
e
The hole diameter is calculated according to the following formula:
D = d +
{
L
2
2
+
[
(
L
1
/2
)
2
-
(
L
2
/2
)
2
+ H
2
]
2
/H
2
}
1/2
Where
”d” is the actual diameter of the rob
Note: the accuracy is optimum when the distance (H) is equal to 1/20 ~ 1/40 of
the hole diameter.
Fig.12 Measuring a hole using electrical methods
Содержание EX-100
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