Set Bore Gauge to nominal bottom point on range using ring gauge with nominal value at 50mm (bottom end of the range).
(1A) Set the micrometer to nominal zero using 20mm Slip block as shown in fig. 1.
The nominal bottom point diameter of 50mm for 50-60mm Head can be achieved by using Ring gauge of ∅50mm. This can also be achieved by using a cylinderical block whose nominal diameter is Ø50mm. Cylinder of nominal value for each micrometer bottom point is required for this method. (See fig. 2 & fig. 3)
Decrease the size of Slip Block in steps of 3mm i.e. take the Slip blocks of sizes 20mm, 17mm, 14mm, 11mm, 8mm and 5mm. With 20mm Slip block, micrometer has been set to nominal zero. When 17mm Slip block is used, the micrometer should read 2mm. Record deviation from micrometer readings.
The increase in micrometer reading from nominal value is a
function of the size of slip block:
The readings of the micrometer for decreasing size of the Slip block is shown in Table 1.
The slip block size is selected according to the range of instrument being calibrated.
i.e. 20mm for all Head ranges within 0-10mm.
40mm for all Head ranges up to 25mm.
ALL READINGS IN (mm)
Reding No
Slip Block Size
(Calibrated)
Calibrated Setting
R2
Micro Meter Readiang
R1
Deviation
(R1-R2)
1
20
0.000
0.000
2
17
2.000
3
14
4.000
4
11
6.000
5
8
8.000
6
5
10.000
1
22/04/07
INFOR. ISSUE
M.S.S
ISSUE No.
ISSUE. DATE
MOCIFICATIONS
APP.BY
INSTRUCTION SHEET REF 25003
1 0FF 1
Pl. note: The illustrations and specificatins may be changed without prior notice.
