Cutting speed in relation to overhang
Chip evacuation and tool vibration are important factors that affect the selection of cutting data.
Recommendations for the chosen insert and grade can be followed generally, but with the following exceptions:
- Maximum recommended starting value for cutting speed is 656 ft/min (200 m/min) for rough boring and 785 ft/min (240 m/min) for fine boring to ensure proper chip evacuation.
- Recommended starting values for cutting speed for fine boring head 391.37A with steel or carbide bars with inserts are 295-393 ft/min (90-120 m/min) (use lower values for long steel bars). Recommended starting value for ground carbide bars is 200 ft/min (60 m/min).
- Maximum recommended depth of cut for fine boring is .020 inch (0.5 mm).
- Cutting speed must be reduced when working with long overhangs.
Silent Tools can be used to achieve higher cutting speeds at certain overhangs.
If the tool is adjusted to minimum possible diameter, chip evacuation will be more critical and it might be necessary to reduce cutting depth.
Maximum feed at fine boring is limited by desired surface finish. The possibility to influence chip form is therefore limited.