View Full Version : Thread Whirling

08-28-2008, 10:07 AM
Anybody Thread Whirl on their Swiss machine? I have a Star 32 Lathe and want to thread whirl some taps & screws. I have an attachment with the 3 insert cassette, how does that compare with 6 inserts? Is it worth upgrading to the 6 insert holder? Where do ya get custom formed inserts (for things like bone screws)? Any tips, tricks, tool suppliers, or general info would greatly be appreciated. Thanks

08-30-2008, 07:13 PM

09-04-2008, 04:36 PM

09-05-2008, 11:09 AM
The concept is similar to the difference of a 2 flute end mill and a 4 flute. There are 3 basic possible improvements:
1. Productivity - The chip load stays the same per tooth, which means productivity increases as a result of faster cutting velocity (C-axis rpm) and a reduce whirling cycle.
2. Finish - The velocity (c-axis feed) stays the same which means the chip load per tooth is reduced.
3. Improved Finish and Productivity - The chip load per tooth is reduced slightly but the overal cutting velocity has increased.

I have done many bone screws both with the Schwanog 6 inserts and Utilis 12 inserts. In both cases the results were better finish and prducitvity. I have found the Utilis system however to have more accurate tip to tip repeatability, this actually had a result on better tool life, productivity and finish becuase each insert had a more even bite during the cut and the machine ran about 25% longer before an insert change was necesary.

The most critical thing with more inserts is to have accuartely aimed high-pressure coolant for chip evacutation, it must be hitting the inserts. Coolant hitting near the inserts is not acceptible becuase the volume of chips being removed is 2 - 4 times greater becuase of the faster cutting time; the coolant must be focused on the inserts or the chips will not evacuate properly.