Page 120 - Threading_Handbook

THREAD TURNING Constant Depth per Pass
This method defines constant depth per pass (except for the last pass), regardless of the
number of passes. The last pass for the finish operation is recommended to be
0.05 - 0.1 mm (0.0019 - 0.0039 inches). This method is less productive than the previous
method, as it causes a larger number of passes and is usually used in cases of problems
with chip control. The chip thickness is constant on each pass, but the chip area on
subsequent passes is larger, respectively, and the load on the tool and material removal rate
increase on each pass. For example, when cutting a 60-degree threading with a constant
depth of 0.25 mm per pass, the second pass removes three times more metal than the first.
And with each passing pass, the value of metal removed increases exponentially.

Number of Passes

The optimal number of passes should be checked in each specific case in order to achieve
maximum effectiveness but, in any case, any pass should not be less than 0.05 mm.
ISCAR’s consultants will be glad to identify the best solution according to the customer’s
threading requirements and production process.

120 ISCAR