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--></style></head><body lang=EN-US link=blue vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Dies are intended to cut new male threads on a pipe or rod. That operation is called threading. A tap is intended to cut female threads in a hole, thus called tapping. Both taps and dies can be used to chase an existing thread, process is chasing. Trick to getting clean, straight threads with a die is to make a chamfer on the end of the pipe or rod, about 30 degrees works well.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>To Tom’s original question it would seem it would take a smaller diameter thread size than a ½ inch die to form a usable thread on a ½ inch outer diameter pipe. The root or minor diameter of the ½ inch thread is just slightly less than the pipe. </p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>However at this point I’m all tapped out……</p><p class=MsoNormal>Perry </p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Sent from <a href="https://go.microsoft.com/fwlink/?LinkId=550986">Mail</a> for Windows 10</p><p class=MsoNormal><o:p> </o:p></p><div style='mso-element:para-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='border:none;padding:0in'><b>From: </b><a href="mailto:jmsdarch@sbcglobal.net">John Spaur</a><br><b>Sent: </b>Wednesday, May 13, 2020 1:39 PM<br><b>To: </b><a href="mailto:bspidell@comcast.net">'Bob Spidell'</a>; <a href="mailto:healeys@autox.team.net">healeys@autox.team.net</a><br><b>Subject: </b>Re: [Healeys] BSF Taps and Dies</p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>With the correctly sized die for the pipe or rod, threads can be cut.</p><p class=MsoNormal>John</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>-----Original Message-----</p><p class=MsoNormal>From: Healeys [mailto:healeys-bounces@autox.team.net] On Behalf Of Bob Spidell</p><p class=MsoNormal>Sent: Wednesday, May 13, 2020 8:18 AM</p><p class=MsoNormal>To: healeys@autox.team.net</p><p class=MsoNormal>Subject: Re: [Healeys] BSF Taps and Dies</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>My (somewhat limited) experience is that the so-called 'dies' are really only thread chasers. If you try to use them to actually thread, say, a pipe or rod the die will wander laterally and you won't get a straight thread. I don't know if actual 'dies' are available outside a machine shop but, probably the only way to get a straight thread is with a lathe.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>On 5/13/2020 6:49 AM, Bob Haskell wrote:</p><p class=MsoNormal>> Tom,</p><p class=MsoNormal>><o:p> </o:p></p><p class=MsoNormal>> If the pipe is 1/2" outside diameter, then a 1/2"-13 UNC or 20 UNF die </p><p class=MsoNormal>> would be used. Pipe is usually given by the inside diameter and </p><p class=MsoNormal>> normally has tapered threads (NPT), in the US. A 1/2" pipe would use </p><p class=MsoNormal>> a 1/2" NPT die which is much larger than the 1/2"-13 or 20 dies.</p><p class=MsoNormal>><o:p> </o:p></p><p class=MsoNormal>> Cheers,</p><p class=MsoNormal>><o:p> </o:p></p><p class=MsoNormal>> Bob Haskell</p><p class=MsoNormal>> Austin Healey 3000 BN7/BT7 registrar</p><p class=MsoNormal>><o:p> </o:p></p><p class=MsoNormal>> On 5/13/20 7:12 AM, Tom Felts wrote:</p><p class=MsoNormal>>> Totally off Healey content, but here is a stupid question Re. dies. I </p><p class=MsoNormal>>> have a piece of 1/2" OD steel pipe I want to thread (the outside).</p><p class=MsoNormal>>> I don't know the die size to use. A 1/2" die seems way too small. </p><p class=MsoNormal>>> Anyone know what size die to use? the number of threads doesn't </p><p class=MsoNormal>>> matter---just the size of the die.</p><p class=MsoNormal>>> Thanks</p><p class=MsoNormal>>> Tom</p><p class=MsoNormal>>><o:p> </o:p></p><p class=MsoNormal>>> ----- Original Message -----</p><p class=MsoNormal>>> From: Michael MacLean <rrengineer.mike@att.net></p><p class=MsoNormal>>> To: 'Healeys' <healeys@autox.team.net>, simon lachlan </p><p class=MsoNormal>>> <simon.lachlan@alexarevel.plus.com></p><p class=MsoNormal>>> Sent: Wed, 13 May 2020 02:51:28 -0400 (EDT)</p><p class=MsoNormal>>> Subject: Re: [Healeys] BSF Taps and Dies</p><p class=MsoNormal>>><o:p> </o:p></p><p class=MsoNormal>>><o:p> </o:p></p><p class=MsoNormal>>> I just want them to clean up threads. Should be adequate for that..</p><p class=MsoNormal>>> Mike M</p><p class=MsoNormal>>><o:p> </o:p></p><p class=MsoNormal>><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>