On Thu, 09 Feb 2012 03:53:21 -0600, DougC
wrote:

On 2/9/2012 1:39 AM, PrecisionmachinisT wrote:
"Tim wrote in message
...
On Thu, 09 Feb 2012 00:18:21 -0600, DougC wrote:

On 2/9/2012 12:06 AM, DougC wrote:
........
I had assumed there would be taps& dies for this. I have found many
sources for cheap dies (pipe threading kits) but no taps yet, and the
dies are "long" because they are for threading pipe.... Is there any
'normal' taps& dies sold for this, at a /relatively/ cheap price? I
just need the one 3/8"-18 size, internal& external.


Well really, it looks like it is easiest& fastest to just order a
T-fitting and nipples already made off of McMaster,,, but I am still
curious.

The methods that I have seen for cutting tapers (or tapered threads) on
a normal lathe is to offset the tailstock, and spin the part between
centers... but you can't do that if you're cutting internal threads.

So that is why I am wondering how to cut internal tapered threads on a
manual lathe without a taper attachment, or if it can even be done.

You can get taps.


Hand grind a few flutes onto an old pipe plug and use it as a ****ing tap
for christ sakes.



What old pipe plug? The local hardware stores only carry blumbing
fittings in plastic, brass, cast iron and some (?) kind of zinc-plated
steel.

I'd have had to order something anyway.... It aint an emergency though.

I've got tapered pipe taps for a few smaller sizes, 1/4, 1/8. You can
buy about any size you'd want, but they get expensive. Try
http://www.mcmaster.com/#pipe-taps/=g67ub6

Pete Keillor