
| Knurling - Course: Techniques for Machining of Material. Instruction Examples for Practical Vocational Training |
This example serves to practise straight knurling of simple cylindrical parts.

Material
St 42 (steel with tensile strength up to 420 MPa)
Dimensions
dia. 62 x 110 mm
Working tools
Right-bent roughing tool, chuck key, straight knurling tool with straight pitch (t = 0.8 mm)
Measuring and testing tools
Vernier caliper
Accessories
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
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M 16: |
M = metric thread. 16 = nominal diameter |
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Straight knurling 0.8: |
straight knurling = straight wheel |
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0.8 = tooth pitch 0.8 mm |
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Sequence of operations |
Remarks | |
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1. |
Dimensional inspection |
dia. 30 x 14 mm |
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2. |
Clamping of workpiece |
Chucking - chuck jaws to chuck on dia. 16 mm, 30 mm deep. |
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3. |
Clamping of tool to produce knurling diameter |
Right-bent roughing tool |
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4. |
Setting of cutting values for turning the outside diameter |
For steel v = 80 m/min. |
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5. |
Producing the knurling diameter |
By experience it is known that diameter of finished part becomes bigger by approx. half the pitch (1/2 mm) of knurling tool, i.e. diameter to be turned smaller - d = 30 mm less 0.4 mm = 29.6 mm. |
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6. |
Tool change for producing knurling |
Width of knurling tool according to width of
workpiece. |
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7. |
Setting of cutting values for straight knurling |
For steel v = 6 to 10 m/min. |
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8. |
Straight knurling of diameter |
To be cooled and lubricated with diluted soluble oil or cutting oil (heavy pressing force results in high friction and heat). |
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9. |
Tool change for producing the chamfers |
Right-bent roughing tool. |
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10. |
Chamfering of workpiece |
Chamfering of workpiece after knurling is necessary because material is forced towards end faces, both ends 0.8 x 45° (chamfer = t). |
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11. |
Unloading of workpiece | |
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12. |
Dimensional inspection |
Dimensional and visual inspection (cleanliness of knurling grooves). Wheel of knurling tool to be cleaned by wire brush. |
