Jon, I hope it doesn't appear as though I am jostling you for the final word, however you pointed out a major difference between us hobbyists and professionals. A professional must deliver a part in spec 100% of the time ( six sigma- don't get me started...) no matter if the part was cut in the cold morning or during a hot afternoon, if the part was mounted at the center of the table or if mounted near the edge, if the machine was being run by your best operator or the guy you hired yesterday.
A tap can wear, but so can a thread mill cutter and probably faster. However, thread milling introduces two additional tolerances that tapping does not. Each of those tolerances can (and eventually will) produce an unacceptable thread. A loose fitting thread can have a LOT less pull-out strength than a properly formed thread. And, you might not be aware of a loose thread unless you have a GO NO-GO gage. In my day job, I want tapped holes from the machine shop (In fact, I am getting quite accustomed to roll-tapping and the superior strength thread it produces). During the weekend, I will enjoy making my own threaded holes with a thread mill. Glenn -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jon Elson Sent: Wednesday, May 21, 2008 9:51 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Thread Milling Glenn R. Edwards wrote: > > Other issues with thread milling: 1)The thread mill tool will not > follow the pre-drilled hole as will a tap. 2)Getting the correct > pitch diameter from a thread mill is a trial and error routine. I don't think so. I bought a single-row 1/4" thread mill from Micro-100. I wrote a program to create the G-code, and after trying one pass in air, I drilled a hole and let it run. It produced a thread as close as I could tell identical to a tap. I didn't have a real certified go/no-go gauge, but a threaded part felt the same in the hole. I was very impressed. I had bought the thing because I had a job coming up that needed an NSEF thread, and I was worried about getting a tap for that. Then a sale flier on special taps crossed my desk, and I was able to get the right tap at a very reasonable price. So, I've only done one job where I needed to thread an off-size hole at a wierd angle. But, it produces a thread with very predictable pitch diameter. Jon ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
