Knurling - Course: Techniques for Machining of Material. Instruction Examples for Practical Vocational Training: Instruction example 7.2.: Ring thread gauge

Knurling - Course: Techniques for Machining of Material. Instruction Examples for Practical Vocational Training

		(introduction...)
		Introduction
		Instruction example 7.1.: Locking screw
		Instruction example 7.2.: Ring thread gauge
		Instruction example 7.3.: Knurled screw
		Instruction example 7.4.: Control knob
		Instruction example 7.5.: Grip

Instruction example 7.2.: Ring thread gauge

This example serves to practise spiral knurling of simple cylindrical parts.

Figure

Material

16 Cr Mn 5 (low-alloy steel, alloy constituents: 0.16% carbon, 1.25% chromium, less than 1% manganese, rest iron)

Dimensions

dia. 52 x 27 mm

Working tools

Right-bent roughing tool, chuck key, spiral knurling tool with groove pitch (t = 1.2 mm)

Measuring and testing tools

Vernier caliper

Accessories

Hard chuck jaws, arbor M 24, supporting plates, coolant and lubricant

Required previous knowledge

Reading of drawings, measuring and testing, behaviour of material in chipless shaping, longitudinal turning and facing, use of coolants and lubricants

Explanations to the working drawing

M 24:	M = metric thread, 24 = nominal diameter
Spiral knurling 1.2:	Spiral knurling: spiral knurling wheels at an angle of 30°.
	1.2 = tooth pitch (groove distance) 1.2 mm

Sequence of operations		Remarks

1.	Dimensional inspection

2.	Clamping of workpiece	Chucking (hard jaws) - centre. Use arbor M 24 to mount ring thread gauge. Arbor to be produced with shoulder to give necessary distance between workpiece and chuck.

3.	Clamping of tool to produce knurling diameter	Right-bent roughing tool.

4.	Setting of cutting values for longitudinal turning

5.	Producing the knurling diameter	t/2 mm: d = 50 mm less 0.6 mm = 49.4 mm

6.	Tool change for producing the knurling	Spiral knurling tool to be clamped approx. 1 mm below centre and at right angle to workpiece axis. Matching edge bearing must fit well.

7.	Setting of cutting values for spiral knurling	v = 6 - 10 m/min. For low-alloy steel v = 6 m/min to be selected.

8.	Spiral knurling of diameter	To be cooled and lubricated with soluble oil or cutting high (heavy pressing force results in high friction and heat). When longitudinal feed is used, feed must correspond to spiral-knurling pitch to avoid overlapping.

9.	Tool change for chamfering	Right-bent roughing tool.

10.	Chamfering of workpiece	Chamfers 1.2 mm x 45° each (chamfer = t). Chamfering to be done after knurling because material is forced towards end faces. v like for producing outside diameter.

11.	Unloading of workpiece

12.	Dimensional inspection	Dimensional and visual inspection. Wheels of spiral knurling tool to be cleaned by wire brush.

Figure