"Karl Townsend" wrote in message ...
On Fri, 04 May 2012 10:49:53 -0500, Jon Elson
wrote:

Ignoramus302 wrote:

On 2012-05-04, PrecisionmachinisT
wrote:


Thread mill in the cnc then chase by hand with a tap




Thread mills are super expensive.
Single-row thread mills are much less expensive, and can be used over a
range of thread pitches. If this job only requires a few parts, that's
what I'd do. Thread milling is an awesome process, and great for things
you don't need a lot of.

Jon

Jon, I surfed MSC and found these run $85+ each and they only do a
small range of thread pitches. Then shipping too. Is there better
pricing someplace else?



Mine was at one point in time an old 5/8 endmill, so it cost me basically nothing unless you count the 10 minutes of my time that I spent dinking around over at the bench grinder...

Generally speaking, I use g41 and treat it as if the tool were actually 5/8in dia--so far a torque requirements go, this eaves me with a very easily manageable amount of excess to chase with an actual tap where an accurate thread form is needed.

Where really works great though, is where you need fairly large diameter taper pipe thread say for instance in a piece of plate stock....