Thread Cutting by Dies and Taps - Course: Techniques for Machining of Material - Instruction Examples for Practical Vocational Training.: Instruction example 5.1. Spring bolt

Thread Cutting by Dies and Taps - Course: Techniques for Machining of Material - Instruction Examples for Practical Vocational Training.

		(introduction...)
		Introduction
		Instruction example 5.1. Spring bolt
		Instruction example 5.2. Ball handle
		Instruction example 5.3. Lance
		Instruction example 5.4. Piston

Instruction example 5.1. Spring bolt

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

Figure

Material

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

Dimensions

Ø 38 x 96

Tools

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

Measuring and testing tools

vernier caliper, thread ring gauge M 20

Accessories

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	Remarks

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