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close this bookKnurling - Course: Techniques for Machining of Material. Instruction Examples for Practical Vocational Training
View the document(introduction...)
View the documentIntroduction
View the documentInstruction example 7.1.: Locking screw
View the documentInstruction example 7.2.: Ring thread gauge
View the documentInstruction example 7.3.: Knurled screw
View the documentInstruction example 7.4.: Control knob
View the documentInstruction example 7.5.: Grip

Instruction example 7.4.: Control knob

This example serves to practise straight knurling of convex parts.



St 34 (St = steel, 34 = tensile strength up to 340 MPa)


dia. 44 x 65 mm

Working tools

Right-offset side-cutting tool, radius turning tool, chuck key, hollow (concave) knurling tool

Measuring and testing tools

Vernier caliper, radius gauge


Hard chuck jaws, 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 16:

M = metric thread, 16 = nominal diameter

Straight knurling K 1.0:

K = hollow (concave) knurling wheel 1.0 = tooth pitch 1 mm

All surfaces finished.

Sequence of operations



Dimensional inspection


Clamping of workpiece

Chucking in hard chuck jaws 40 mm deep.


Clamping of tool to produce outside diameter

Right-offset side-cutting tool.


Setting of cutting values


Producing the outside diameter

t/2: d = 42 mm less 0.5 mm = 41.5 mm


Tool change for producing the radius

Form turning tool to be selected according to radius of knurling tool.


Setting of cutting values

Form turning tool is made of high-speed steel -
v = 25 - 50 m/min.
v = 25 m/min to be selected for form turning.


Producing the radius

Radius turning tool to be in centre position.


Tool change for producing knurling

Straight knurling tool to be clamped approx. 1 mm below centre and at right angle to workpiece axis.


Setting of cutting values

v = 6 - 10 m/min, since concave knurling wheel
v = 6 m/min to be selected.


Straight knurling of diameter

To be cooled and lubricated with soluble oil or cutting oil. First knurling to be done with one feed setting, if possible.
Tool to be positioned over full width - central position is essential Operation must not last longer than necessary since surface gets harder and more brittle because of pressure.


Deburring of edges of knurled portion

Material is forced towards end faces forming burr.


Unloading of workpiece


Dimensional inspection

Dimensional and visual inspection (cleanliness of knurling grooves).
Knurling wheel to be cleaned by wire brush.