Randy333 wrote:

On Mon, 25 Mar 2013 14:59:19 -0600, "Pete C."
wrote:


Physically they are a comparable size and material quantity as a similar
tap or similarly sized end mill, only the geometry of them is really
different. Since all these tools are presumably produced on the same
multi axis CNC grinders, why the cost difference? Is it just because
they are newer technology?

Why can you not get a HSS thread mill, all I want to cut is 6061
aluminum.

MSC lists some non-carbide thread mills, cobalt or powdered metallurgy
stuff, but it isn't any cheaper.


Thread mills are used in "aerospace" work, that jacks up the price a
bunch.

That's my theory since I can't see any reason for a difference in
manufacturing cost vs. a comparable size tap. Indeed a tap for the same
thread size will have a bit more material since it has to be the full
dia vs. a thread mill which has to clear all the threads.


Only used them once to cut big threads on a brass part, sold them to
my customer as part of the deal. 11.5 TPI NPS was a bitch to find.

Searching around I see plenty of options out there, but none are cheap.
I'll probably pick up something cheap-ish on fleabay just so I can try
it out to see how it runs on my machine. If you can thread mill, there
isn't much reason to bother trying to upgrade the machine to do rigid
tapping, and thus avoid the work trying to fit a spindle encoder.