| USA Ra(µm) |
USA Ra (Micro inch) |
USA RMS (Micro inch) |
Machining Finish Method |
| 50.0 |
2000 |
2200 |
The most coarse machining or good rough casting surfaces |
| 25.0 |
1000 |
1100 |
Machining marks very obvious. Rough turning, boring, planning, drilling |
| 12.5 |
500 |
550 |
Machining marks obvious. Normal turning, boring, planning, drilling, grinding |
| 8.00 |
320 |
352 |
Machining marks visible. Normal turning, boring, planning, drilling , grinding |
| 6.30 |
250 |
275 |
Machining marks visible. Normal turning, boring, planning, drilling , grinding |
| 5.00 |
200 |
220 |
Machining marks not obvious. But still visible. Normal turning, boring, planning, drilling, grinding. |
| 4.00 |
160 |
176 |
Machining marks not obvious. But still visible. Normal turning, boring, planning, drilling, grinding. |
| 3.20 |
125 |
137.5 |
Machining marks not obvious. But still visible. Normal turning, boring, planning, drilling, grinding. |
| 2.50 |
100 |
110 |
Machining marks blur, but direction obvious. Number controlled turning, boring, planning, drilling, grinding. |
| 2.00 |
80 |
88 |
Machining marks blur, but direction obvious. Number controlled turning, boring, planning, drilling, grinding. |
| 1.60 |
63 |
69.3 |
Machining marks blur, but direction obvious. Number controlled turning, boring, planning, drilling, grinding. |
| 1.25 |
50 |
55 |
Machining marks direction blur, but still visible. Number controlled turning, boring, planing, drilling, grinding. |
| 1.00 |
40 |
44 |
Machining marks direction blur, but still visible. Number controlled turning, boring, planing, drilling, grinding. |
| 0.80 |
32 |
35.2 |
Machining marks direction blur, but still visible. Number controlled turning, boring, planing, drilling, grinding. |
| 0.63 |
25 |
27.5 |
Machining marks direction blur. Reaming, grinding, boring, rolling. |
| 0.50 |
20 |
22 |
Machining marks direction blur. Reaming, grinding, boring, rolling. |
| 0.40 |
16 |
17.6 |
Machining marks direction blur. Reaming, grinding, boring, rolling. |
| 0.20 |
12.5 |
13.75 |
Machining marks direction invisible. Grinding, super machining |
| 0.20 |
10 |
11 |
Machining marks direction invisible. Grinding, super machining |
| 0.20 |
8 |
8.8 |
Machining marks direction invisible. Grinding, super machining |
| 0.10 |
4 |
4.4 |
Surface dark gloss. Surper machining |
