Page 852 - Tungaloy Catalog

Machining with offset on the lathe

● Drilling with offset
 When drilling on the lathe, the hole diameter can be adjusted by offsetting the drill body along the X-
axis of machine.
 When drilling with offset, the drill body must be correctly mounted with cutting edges parallel to the
X-axis of the machine. “Mounting the drill on the turret” can be viewed on page 11-34.

X-axis of machine

Direction of
Interferences Central edge Central edge increased diameters
Direction of de- Peripheral edge
Peripheral edge
Offsetting to the creased diam-
direction of Offset value must be eters
less than .004".
decreased diameters

Hole diameter machined with offset are roughly
calculated as following.
Drilled diameter Offset value (+)
= Drill diameter + offset value x 2 drill body. Central edge
Example:
depends on each
Drill diameter: ø1.125" Peripheral edge
Offset value: .020"
Drilled hole diameter = 1.125 + .020 x 2 = ø1.165" Offsetting to the
11 direction of increased
diameters

Drilling Tools Shapes of hole bottom

TungSix-Drill provides a more even hole bottom face than with HSS drills!

Hole bottom shape obtained with TungSix-Drill
The shape of the hole bottom machined with TungSix-Drill is
flatter compared with those machined with HSS drills. Drill diameter øDc
Maximum deviation
Drill ø1.125 ø1.312 ø1.562 ~ ø1.875 ~
diameter
2.000
~1.250
~1.500
1.812
øDc (in)
Hmax (in) .069 .083 .096 .105 Hmax Hmax

11–36 Relating Cutting Conditions Technical reference
pages
(11-14 )
(14-1)