Martin&Tschopp三線規
- 三線規安裝於測微器之心軸、測砧的兩量測面，以量測螺絲的有效直徑
| 公制螺牙對照表 |
| 公制 |
螺距 P |
三線規直徑dm |
| M1 |
0.25 |
0.170 |
| M1.2 |
| M1.4 |
0.30 |
| M1.7 |
0.35 |
0.220 |
| M2 |
0.40 |
0.250 |
| M2.3 |
| M2.6 |
0.45 |
0.290 |
| M3 |
0.50 |
| M3.5 |
0.60 |
0.335 |
| M4 |
0.70 |
0.455 |
| M5 |
0.80 |
| M6 |
1.00 |
0.620 |
| M8 |
1.25 |
0.725 |
| M10 |
1.50 |
0.895 |
| M12 |
1.75 |
1.100 |
| M14 |
2.00 |
1.350 |
| M16 |
| M20 |
2.50 |
1.650 |
| M22 |
| M24 |
3.00 |
2.050 |
| M27 |
| M30 |
3.50 |
| M33 |
| M36 |
4.00 |
2.550 |
| M39 |
| M42 |
4.50 |
| M45 |
| M48 |
5.00 |
3.200 |
| M52 |
| M56 |
5.50 |
| M60 |
| M64 |
6.00 |
4.000 |
| M68 |
| 美制 / 英制螺紋對照表 |
| 牙數TPI |
鋼絲尺寸 |
牙數TPI |
鋼絲尺寸 |
| 60 |
0.250 |
18 |
0.895
|
| 48 |
0.335 |
16 |
| 44 |
15 |
| 40 |
0.390 |
14 |
1.100
|
| 36 |
0.455
|
13 |
| 34 |
12 |
1.350
|
| 32 |
11.5 |
| 30 |
0.530
|
11 |
| 29 |
10 |
1.650
|
| 8 |
9 |
| 26 |
0.620 |
8 |
2.050
|
| 24 |
7 |
| 22 |
0.725
|
6 |
2.550 |
| 20 |
5 |
3.200
|
| 19 |
4.5 |
