CENTERLESS GRINDING ALLOWANCES
|
Minimum allowance for removal of OD imperfections
|
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|
Finished OD
Inches |
0.125 and
Under |
Over 0.125
to 0.180 |
Over 0.180
to 0.230 |
Over 0.230
to 0.360 |
Over 0.360
to 0.460 |
Over 0.460
to 0.580 |
|
Up to 3.000
|
0.012
|
0.014
|
0.016
|
0.020
|
0.022
|
|
|
Over 3.000 to 4.750
|
0.016
|
0.018
|
0.020
|
0.022
|
0.024
|
0.026
|
|
Over 4.750 to 6.000
|
0.018
|
0.020
|
0.022
|
0.024
|
0.026
|
0.028
|
|
Over 6.000 to 7.000
|
0.020
|
0.022
|
0.024
|
0.026
|
0.028
|
0.030
|
|
Over 7.000 to 8.000
|
|
0.024
|
0.026
|
0.027
|
0.028
|
0.031
|
|
Over 8.000 to 10.500
|
|
|
0.026
|
0.028
|
0.030
|
0.032
|
|
Over 10.500 to 12.500
|
|
|
0.028
|
0.030
|
0.032
|
0.034
|
|
Over 12.500 to 14.000
|
|
|
0.030
|
0.032
|
0.034
|
0.036
|
|
Over 14.000 to 15.000
|
|
|
0.033
|
0.035
|
0.036
|
0.037
|
NOTE: These allowances plus normal size tolerances must be considered in calculating the size to be ordered.CENTERLESS GRINDINGS
Example #1:
Determine ordering size for tube to be centerless ground to 4.750”OD x .440” wall.Step 1Determine ID size:4.750”finished OD Less 2 x wall thickness (.440”)-.880” 3.870”IDStep 2Apply centerless grinding allowances to OD: Finished OD of 4.750” Takes .024” centerless grinding allowance from table1 4.750” + .024” 4.774”Step 3Add ID and OD tolerance and order: 4.774” OD + .013” – .000″ x 3.870″ ID +.000″ -.013