MINIATURE SCREW THREADS (S)

(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