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Drilling A Workpiece - OTMT SC4 User Manual And Installation Manual

Bench lathe
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close to the end of the workpiece. Lock the
tailstock in place.
6. Check to make sure that the tailstock ram
lock lever (located near the front of the
tailstock) is not in the locked (tightened)
position. Unlock it if necessary by turning it
counterclockwise about ½ turn.
7. Apply a few drops of cutting fluid to the tip
of the drill bit
8. Check to make sure that the area around
the chuck is free from any hazards, then
press the green Start button.
9. Set the speed to about 800 RPM. Make
sure that the chuck is rotating in the
Forward (counterclockwise) direction.
10. Use the tailstock handwheel to advance the
tip of the center drill into the workpiece.
11. Continue advancing the drill tip into the
workpiece until the angled portion of the
completes the depth for the center drill hole.
12. Withdraw the center drill from the hole and
then press the Stop button.
13. Disengage the tailstock cam lock lever,
then slide the tailstock towards the right
end of the lathe.
14. Remove the center drill from the drill chuck
and return it to its storage location.
Completed center-drilled hole
The completed hole should have a smooth,
even appearance.
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Drilling a Workpiece

The procedure for drilling a hole into the
workpiece is similar to the center-drilling
operation except that the drilled hole usually is
deeper. Sometimes the hole is drilled only part
way into the workpiece; in other cases, for
relatively short workpieces, the hole may be
drilled all the way through until the drill bit
emerges from the opposite end of the
In either case, if the hole to be drilled is more
than about three times the diameter of the drill
bit, it is regarded as a "deep hole". When
drilling deep holes the drill bit should be
withdrawn from the hole to allow chips to be
cleared after every advance of about three drill
bit diameters.
The drill bit can be withdrawn by reversing the
rotation of the tailstock handwheel while the
work is still rotating. If the hole is "very deep",
say ten times the diameter of the drill or more,
it may save time to unlock the tailstock and
slide the tailstock towards the back of the lathe
to clear the chips. The tailstock can then be
advanced until the drill bit reaches the point
where it left off to continue drilling the hole.
Failure to clear chips from a deep hole can
cause the chips to "weld" to the surface of the
drill bit or the workpiece resulting in an
oversized hole with rough, uneven walls.
Cutting fluid will also help to prevent welding of
the chips and is recommended for nearly all
drilling operations on the lathe. A few drops
applied to the tip of the drill bit each time it is
Drilling a workpiece