NPT THREAD MILLING

[dfearnow]

I hardly have to thread mill, and never had to NPT thread mill.
So with that being said, I have to drill and thread a 304 SS ring with (6) 1/2-14 NTP. Need to know what cutter to use, Single point or taper multi tooth. And exactly how to do it. Step over amounts? Taper thread mill? Its a pretty big job, so I hope someone can help. Figured I would post here before spending hours trying to test it. Thanks.

[txcncman]

Once you choose your tool, your tool supplier will help you with specifics for that tool for speeds, feeds, and depths of cut.

I prefer "single point" thread mills because I can usually cut a wider variety of thread sizes with a single tool. With a "multi point" tool, you are locked in by both shank size and available insert sizes. 1/2"-13 takes a certain shank with one insert. 1/2"-20 takes the same shank, but a different insert. With the "single point" tool, both threads, same tool. "Single point" tools mean longer cycle times and one "single point" tool costs more than one "multi point" insert.

Contact your local/favorite tool supplier for their recommendations. If you do not have a local one, try Grainger, MSC, or Travers. Travers has the best tech support and application engineers in my opinion. The others just have sales people.

[John_B]

I would suggest the Vardex threadmills for good cost/life balance. Also would suggest multi-tooth inserted over single tooth for anything but the smallest of jobs - the cycle time is only seconds with multi-tooth style and they last longer because each tooth is only doing a little bit of work.

The feed & speed suggestions Vardex offers are a good place to start, then you'll need to drive it a bit to find what you can do with it. I wound up kinda close to their starting point after monkeying with it for quite a while.

I currently run their 1/4" NPT tool up to the 2"NPT, as well as a few of their straight thread cutters. They do a good job for me.