When ordering special end mills specify: 

1. Diameter of cut
2. Diameter of shank
3. Length of cut
4. Length overall
5. Style (Number of flutes, ball nose, etc.)
6. Single end of double end

Attention to the details will help you to accurately determine your own requirements and will avoid errors in filling your orders. All tolerances to be manufacturers standards unless specified.

SELECTION OF END MILLS

In selection and use of end mills several precautions should be observed for best results. A milling machine with ample power should be used. Select an end mill of proper design and mount it with the least possible overhang.

The end mill must be sharp, and must run as concentric as possible. Scored or batters end mill shanks contribute to lack of concentricity. Emphasize rigidity of the individual job set up. The best aligned spindle-holder-end mill combination is ineffective if the set up is top light, work insecurely clamped, improperly clamped, or improperly supported.

To determine selection of either a two-flute or a multiple-flute end mill, several basics must be considered:

1. Type of cut
2. Chip space required
3. Production rate desired
4. Surface finish required

Two-flute end mills have a greater chip handling capacity than multiple-flute end mills. Two-flute end milts are center cutting and may be used to plunge-cut. Multiple flute end mills must be center cutting to enable plunge-cutting.

When two-flute end mills and multiple-flute end mills are run at the same feed rate (inches per minute), multiple-cute end mills will produce finer finishes and longer tool life than two-fIute end mills. This is due to a lighter chip load per tooth.

Higher production rates may be achieved with multiple-flute end mills because direct feed per tooth is in direct proportion to the number of flutes, enabling an increase in feed (inches per minute).

CLIMB vs. CONVENTIONAL MILLING

From the very beginning of the milling process, it was found practical to always rotate the end mill opposite the feed of the work. This is termed conventional milling.

In conventional milling the end mill engages the work piece at the bottom of the cut. The end mill teeth slide along until sufficient pressure builds up to break through the surface of the work. This sliding action under pressure tends to abrade the periphery of the end mill with resultant dulling. Also, in horizontal conventional milling, the cutting action has a tendency to lift the work piece, fixture and table from their bearings.

In recent years, milling machines have been greatly improved through backlash elimination and greater rigidity so that climb milling is now possible.

In climb milling, the end mill rotates in the direction of the feed. The tooth meets the work at the top of the cut at the thickest portion of the chip. This provides instant engagement of the end mill with the work piece producing a chip of definite thickness at the start of the cut without the rubbing action resulting from conventional milling. It further permits the gradual disengagement of the teeth and work so that feed marks are largely eliminated.

Climb milling will often provide better product finish, permit greater feed per tooth, and prolong cutter life. It is particularly desirable to climb mill heat treated alloys, steels and non-free machining grades of stainless steel for better tool life and to reduce work hardening It is not recommended on material having a hard scale, such as cast or scaly forged surfaces, as abrasion would quickly ruin the cutting eaves. Also some very soft steels do not lend themselves to climb milling because of the tendency to drag and tear.

Climb milling cannot be applied to every milling operation and should not be attempted if the material and machine setup are not adapted to this type of milling.