JOB SEQUENCE
STEP TURNING, KNURLING AND TAPER TURNING
AIM: To turn the model as given figure
TOOLS AND INSTRUMENTS REQUIRED: Round nose tool, parting tool, knurling tool, steel rule and outside caliper
SEQUENCE OF OPERATIONS:
1. The round nose tool is centered for facing operation.
2. The given rod is fixed in the chuck such that, about 40 mm is projecting from the chuck.
3. The end is faced and chucked for the centering of the tool.
4. The tool is set for turning and the job is turned to 25 mm diameter in stages, to a length of slightly more than 40 mm.
5. Now the step f 18' 20 is turned in stages.
6. An under-cut is taken with the parting tool, to a depth of 3 mm after 30 mm length and also the shoulder is corrected is 20 mm longer.
7. The knurling tool is fixed in the tool post and the knurling operation is completed.
8. Both the edges of knurling is chamfered.
9. The job is reversed and held in the chuck on f 18' 20
10. The remaining length is turned to f25
11. The end is faced until the total length is 70 mm.
NOTE: If the excess length to be removed is substantial; it will be done by parting, followed by facing.
12. Under cutting the step ø 18x10 is done with a parting tool and the shoulders are corrected.
13. The taper angle θ is calculated, using the formula,
Tan θ = (D-d)/2L
Where D= Big Diameter
d= Small Diameter
L= Length of Taper
14. The compound rest is set to the taper angle.
15. The taper is turned in stages, using the compound slide feeding and cutting from right to left.
RESULTS: The model consisting of step turning, knurling and taper turning is thus made, by following the sequence of operations as mentioned above.
