6.Difficulty of
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 braking 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
| Speed | |
Material | 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 | |
Ordinary Brass and Bronze | 200 | - 300 |
Aluminum and its Alloys | 200 | - 300 |
Magnesium and its Alloys | 250 | - 400 |
Slate, Marble, and Stone | 15 | |
Plastics and similar material (Bakelite) | 100 | - 150 |
Wood | 300 | |
Titanium Alloys | 10 - 25 | |
Titanium Alloy Sheet | 50 - 60 | |
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
WARNING: MAKE SURE TO DISCONNECT ELECTRICAL POWER TO THE DRILL PRESS TO AVOID THE POSSIBILITY OF INADVERTENT OPERATION AND EXPOSURE 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 opera- tion.
Replacement of Motor
WARNING: MAKE SURE TO DISCONNECT ELECTRICAL POWER TO THE DRILL PRESS TO AVOID THE POSSIBILITY OF INADVERTENT OPERATION AND EXPOSURE TO POTENTIALLY LETHAL VOLTAGE LEVELS.
1.Disconnect electrical power to drill press.
2.Remove drive belt (refer to 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 (refer to Replacement of Drive Belt).
10.Operate drill press to verify proper operation.
Lubrication
Following are lubrication recommendations for drill press components.
1.Spindle pulley drive: Lubricate spindle splines occasionally with light grease.
2.Quill, Table, and Column: Lubricate with light film of oil.
3.Table lift rack: Lubricate regularly with SAE20 oil (clean rack with solvent before applying oil.)
4.Variable speed drive fork: Lubricate contact points occasionally with grease.
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