Civil Engineering Reference
In-Depth Information
Fig. 4.21. This is a selection of ER collets. The groove around the collet needs care-
ful insertion into the collet nosepiece to avoid damage. Tilt the collet as you insert it
so the groove enters the nose piece properly. A little careful practice without forcing
the collet will soon have you inserting and removing collets easily.
Other collets
There are other types of collet holders that are similar to Autolock holders: the
Clare system, the Osborne Titanic chuck and one made by Kenametal. None
of these systems is as popular as the Autolock system. Cutters are fitted to
these systems on the same principle as an Autolock holder; if in doubt, refer
to the manufacturer's literature.
FEEDS AND SPEEDS
The correct speeds for different materials
Cutting speeds for milling cutters have been determined through trial and er-
ror in industry over many years. They will give an optimum tool life and a reas-
onable surface finish. Speeds are normally recommended in Surface Speed
in Feet per Minute. Speeds and feeds used on an industrial milling machine,
where most of the cutters will be made of tungsten carbide, will be a lot higher
than those used where HSS tools are normally used.
