11
Indication of Extreme Speeds and Feeds
A drill that splits up the web is evidence of too
much feed or insufficient tip clearance at the
center as a result of improper grinding. The
rapid wearing away of the extreme outer corners
of the cutting edges indicates that the speed is
too high. A drill chipping or breaking out at the
cutting edges indicates that either the feed is too
heavy or the drill has been ground with too much
tip clearance.
Speeds for High Speed Steel Drills
Material Speed
In
SFM
Alloy Steel — 300 to 400 Brinell ..................... 20 - 30
Stainless Steel............................................... 30 - 40
Automotive Steel Forgings ............................. 40 - 50
Tool Steel, 1.2C ............................................. 50 - 60
Steel, .4C to .5C ............................................ 70 - 80
Mild Machinery Steel, .2C to .3C .................. 80 - 110
Hard Chilled Cast Iron ................................... 30 - 40
Medium Hard Cast Iron ................................ 70 - 100
Soft Cast Iron ........................................... 100 – 150
Malleable Iron ............................................... 80 – 90
High Nickel Steel or Monel ............................ 40 – 50
High Tensile Bronze ..................................... 70 -150
Ordinary Brass and Bronze ........................ 200 - 300
Aluminum and its Alloys ............................. 200 - 300
Magnesium and its Alloys .......................... 250 - 400
Slate, Marble, and Stone ................................ 15 -25
Plastics and similar material (Bakelite) ....... 100 - 150
Wood ......................................................... 300 -400
Titanium Alloys .............................................. 10 - 25
Titanium Alloy Sheet ...................................... 50 - 60
General Applications
5mm hole .................................................. 550 - 600
10mm hole ................................................ 250 - 300
15mm hole ................................................ 100 - 110
In cases where carbon steel drills are applicable,
the drill should be run at speeds of from 40 to 50
percent of those given above.
Maintenance
Replacement of Drive Belt
Make sure to disconnect
elec-trical power to the drill press to avoid
the possibility of inadvertent operation and
expo-sure to potentially lethal voltage levels.
1. Start drill press. Set speed control to highest
speed. Stop drill press.
2. Disconnect electrical power to drill press.
3. Remove head cover.
4. Remove belt. (With speed control setting at
the highest speed, the belt should be loose
enough to remove.)
5. Install the replacement belt. Install the head
cover.
6. Connect electrical power to the drill press.
7. Operate the drill press to verify correct
operation.
Replacement of Motor
Make sure to disconnect
elec-trical power to the drill press to avoid
the possibility of inadvertent operation and
expo-sure to potentially lethal voltage levels.
1. Disconnect electrical power to drill press.
2.
Remove drive belt (see
Replacement of Drive
Belt
).
3. Disconnect electrical wiring from motor junction
box.
4. Remove nuts and washers from bolts
securing motor to drill head. Remove motor.
5. Remove pulleys and related components
from motor shaft.
6. Install pulleys and related components on
replacement motor shaft.
7. Install motor on mounting bolts and secure
with nuts and washers.
8. Connect electrical wiring (refer to
Wiring
Diagram
section for wiring details).
9. Install drive belt (see
Replacement of Drive
Belt
).
10.
Operate drill press to verify proper
operation.
Lubrication
Following are lubrication recommendations for
drill press components.
Spindle pulley drive: Lubricate spindle
splines occasionally with light grease.
Quill, Table, and Column: Lubricate with
light film of oil.
Table lift rack: Lubricate regularly with
SAE20 oil (clean rack with solvent before
applying oil.)
Variable speed drive fork: Lubricate contact
points occasionally with grease.
