Miniature Screw Thread (S)
Miniature Screw Thread Profile
- Thread form angle : 60°
- P : Pitch
- H : Height of fundamental triangle
- H1 : Height of thread on basic profile
- h3 : Height of external thread on design profile
- ac : Clearance between minor diameters on design profile
- D : Major diameter of internal thread
- D1 : Minor diameter of internal thread
- D2 : Pitch diameter of internal thread
- d : Major diameter of external thread
- d1 : Minor diameter of external thread
- d2 : Pitch diameter of external thread
- d3 : Minor diameter of external thread on design profile
Miniature Screw Thread Tolerance
- T : Tolerance
- TD1, TD2 : Tolerance for D1, D2
- Td1, Td2 : Tolerance for d1, d2
- ES : Upper deviation of internal thread
- es : Upper deviation of external thread
- EI : Lower deviation of internal thread
- ei : Lower deviation of external thread
- G, H : tolerance positions for lower deviation of internal thread
- h : tolerance positions for upper deviation of external thread
(a) Example of internal thread S Profile : S0.9 x 0.225 – 4H5
- S : Miniature thread symbol
- 0.9 : Size
- 0.225 : Pitch
- 4H5 : Tolerance class
- 4H : Pitch diameter tolerance symbol. “4” : tolerance grade and “H” : tolerance position
- 5 : Minor diameter tolerance grade
For internal threads, there are four tolerance classes, 3G5, 3G6, 4H5 and 4H6.
(b) Example of external thread S Profile : S0.9 x 0.225 – 5h3
- S : Miniature thread symbol
- 0.9 : Size
- 0.225 : Pitch
- 5h3 : Tolerance class
- 5h : Pitch diameter tolerance symbol. “5” : tolerance grade and “h” : tolerance position
- 3 : Major diameter tolerance grade
For external threads, there is only one tolerance class, 5h3
Miniature Screw Thread Dimension
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Height of fundamental triangle :
H =
0.000
mm
Height of thread on basic profile :
H1 =
0.000
mm
Height of external thread on design profile :
h3 =
0.000
mm
Clearance between minor diameters on design profile :
ac =
0.000
mm
Major diameter (mm)
0.000
0.000
0.000
=
Minor diameter (mm)
0.000
0.000
0.000
=
Pitch diameter (mm)
0.000
0.000
0.000
=
For not specified tolerance, we use the pitch tolerance to calculate the average value.
Miniature Screw Thread Basic Designation
External Thread
S0.3×0.08 5h3
S0.35×0.09 5h3
S0.4×0.1 5h3
S0.45×0.1 5h3
S0.5×0.125 5h3
S0.55×0.125 5h3
S0.6×0.15 5h3
S0.7×0.175 5h3
S0.8×0.2 5h3
S0.9×0.225 5h3
S1x0.25 5h3
S1.1×0.25 5h3
S1.2×0.25 5h3
S1.4×0.3 5h3
Internal Thread
S0.3×0.08 3G5 , S0.3×0.08 3G6 , S0.3×0.08 4H5 , S0.3×0.08 4H6
S0.35×0.09 3G5 , S0.35×0.09 3G6 , S0.35×0.09 4H5 , S0.35×0.09 4H6
S0.4×0.1 3G5 , S0.4×0.1 3G6 , S0.4×0.1 4H5 , S0.4×0.1 4H6
S0.45×0.1 3G5 , S0.45×0.1 3G6 , S0.45×0.1 4H5 , S0.45×0.1 4H6
S0.5×0.125 3G5 , S0.5×0.125 3G6 , S0.5×0.125 4H5 , S0.5×0.125 4H6
S0.55×0.125 3G5 , S0.55×0.125 3G6 , S0.55×0.125 4H5 , S0.55×0.125 4H6
S0.6×0.15 3G5 , S0.6×0.15 3G6 , S0.6×0.15 4H5 , S0.6×0.15 4H6
S0.7×0.175 3G5 , S0.7×0.175 3G6 , S0.7×0.175 4H5 , S0.7×0.175 4H6
S0.8×0.2 3G5 , S0.8×0.2 3G6 , S0.8×0.2 4H5 , S0.8×0.2 4H6
S0.9×0.225 3G5 , S0.9×0.225 3G6 , S0.9×0.225 4H5 , S0.9×0.225 4H6
S1x0.25 3G5 , S1x0.25 3G6 , S1x0.25 4H5, S1x0.25 4H6
S1.1×0.25 3G5 , S1.1×0.25 3G6 , S1.1×0.25 4H5 , S1.1×0.25 4H6
S1.2×0.25 3G5 , S1.2×0.25 3G6 , S1.2×0.25 4H5 , S1.2×0.25 4H6
S1.4×0.3 3G5 , S1.4×0.3 3G6 , S1.4×0.3 4H5 , S1.4×0.3 4H6
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