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Scout 320 REV 3:2018
5.8.3 Bar Stock Preparation
The bar stock must be free of burrs, chips and excessive dirt. Clean bars will extend the life of
the channel guides and bearing unit of the pusher as well as the oil pump impeller. The bar
ends should be relatively square to the length of the bar.
Chamfers on the bar ends are generally not needed except when the stock OD is close to the
bar pusher OD. In this case the wall of the pusher collet is thin and has only a small lead-in
chamfer.
Profiled material such as hex and square stock should have a generous chamfer on the bar
feeder end of the bar. This chamfer will help negate the offset of the bar centerline to that of
the bar pusher when the stock falls differently into the channel (corners up versus flats up).
Chamfers on the lathe end of the bar are not usually required, only an edge break to ensure no
burrs remain to snag on the lathe collet.
RPM Limiting Factors
Certain conditions may limit the lathe to less than full speed rotation of the spindle. Among these
conditions are the following:
•
Bent bars (bar stock with straightness of less than .5mm/1 meter.
•
Bars with an irregular profile or shaped material.
•
Improperly sized guide channel in relation to the bar stock diameter.
•
Incorrect sizing of guide blocks or incorrect adjustment of steady rollers.
•
Lack of support in the lathe spindle for the bar pusher.
•
Characteristics of the bar stock (copper, brass, plastic ect.).
•
Improper viscosity lubricant in the oil tank of the bar feeder.
•
Unbalanced bar stock.
•
Sheared bar ends.
•
Non-concentric chamfered bar end when using an ejection collet.
These factors may work alone or in combination to cause a vibration that requires a reduction in
the lathe spindle speed.
