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close this bookThread Cutting by Dies and Taps - Course: Techniques for Machining of Material - Instruction Examples for Practical Vocational Training.
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View the documentIntroduction
View the documentInstruction example 5.1. Spring bolt
View the documentInstruction example 5.2. Ball handle
View the documentInstruction example 5.3. Lance
View the documentInstruction example 5.4. Piston

Instruction example 5.1. Spring bolt

This example focuses attention on thread cutting by dies on simple cylindrical workpieces.



stand. 42 (steel with a tensile strength of up to 420 MPa)


Ø 38 x 96


recessed right-side cutting turning tool, die M 20, chucking spanner

Measuring and testing tools

vernier caliper, thread ring gauge M 20


extendable chucking jaws, rotating tip, log measure 45 mm, coolants and cutting compounds

Required previous knowledge

drawing comprehension, measuring and testing, thread cutting by hand, longitudinal turning and surfacing, possibilities and employment of chucking and accessories

Workshop drawing explanations

M 20:

M = metric thread

All surfaces have been machine-finished.

20 = nominal diameter

Sequence of operations


1. Dimensional inspection

2. Clamp workpiece

Clamping in extendable jaws to Ø 36 mm

3. Clamp tool

4. Set the cutting values for longitudinal turning

5. Yield thread Ø M 20

Clamping - rotational tip in diameter 20 mm x 45 mm to 19.8 mm as, whilst cutting, the external diameter increases by about 1/10 of the thread increment amount.
Deburring of the workpiece 2.5 mm x 45°!

6. Set the cutting values for thread cutting

For steel v = 3 - 4 m min-1

7. Position die

Straight positioning by pressing down the quill

8. Cut the thread

It is sensible to cut a few turns by hand whilst the machine is switched off. Ensure proper cooling and lubrication.
Keep the chip chambers clean.
Ensure that the tool frame of the die holder is supported.
Prior to machine reverse also turn back several times by hand.

9. Unload the workpiece

10. Dimensional inspection

Spring bolt