8. Counterboring/countersinking with counterbore/countersink and turning tool
Counterboring/countersinking with counterbore/countersink and
turning tool is a finishing operation on the internal surface of internally
premachined rotationally symmetrical parts. Counterboring/countersinking on the
lathe with special counter-bores/countersinks is of minor importance. Essential
advantages are achieved by counterboring/countersinking on the lathe with the
turning tool which results in higher surface finish and dimensional accuracy
with less tooling costs.
- The cutting is done by turning tools using
counterboring/countersinking tools (see Fig. 5, 6, 14 in section 2).
- Combination tools (piloted counterbore, step countersink,
combination countersink) can be economically used since several operations are
combined into a single one.
- Counterbores/countersinks with straight shank are chucked in a
drill chuck; counterbores/countersinks with taper shank are inserted in the
taper hole of the sleeve.
- When working with the counterbore/countersink, a relatively
low speed rate is to be selected to avoid chatter marks (scratches, grooves).
- During counterboring/countersinking of parts made of steel,
cast steel, red brass or light metal, coolants or lubricants are to be used to
improve the surface finish.
Chips must never be removed by hand - danger of accidents!
What are the advantages of step countersinks and combination
countersinks?
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Why is the counterboring/countersinking technique on the lathe
with special counterbores/countersinks of minor
importance?
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