Page 147 - Threading_Handbook
P. 147
Feed (F)
Feed per revolution (F) always is a constant value that equal to the threading pitch.
For example:
• In order to produce threading with a 2 mm pitch, the feed will be 2 mm/rev THREAD TURNING
(mm per revolution).
• In order to produce threading with 14 TPI, the feed will be 1.8 mm/rev (mm per revolution).
In this case, the definition of the value of the feed per revolution (F) is required to convert a
value of TPI to pitch in mm, i.e.
25.4 ≈ 1.8 mm
14 TPI
Usable Formulas
1 inch = 25.4 mm
25.4
= Pitch (mm)
T.P.I
Cutting Speed (Vc)
The starting cutting speed can be defined as the following formula:
Vc = Ks x Vo
When:
Vc — Starting cutting speed
Ks — Stability factor
Vo — Basic cutting speed
Stability Factor (Ks) is defined by the below estimate of threading operation stability:
For normal stability: Ks=1
For unstable operations such as: high overhang, poor clamping and etc.: Ks=0.7
• Basic cutting speed (Vo) is determined in the table below,
according to carbide grade and workpiece material.
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