On Fri, 31 Oct 2008 04:28:47 -0700 (PDT), Jim Wilkins
wrote:

On Oct 31, 2:17*am, Bruce L. Bergman
wrote:
...
* And if it isn't the 1" pipe thread screw in style, get another
heater element - you'll play hell duplicating that four bolt flange.
And the elements are easier to get.

* *They sell adapters for going the other way - a four bolt flange
with the 1" threaded bung in the center.

* -- Bruce --

I found out the hard way that heater element threads are straight o-
ring (STOR) rather than tapered pipe (NPT). They may not even be
exactly STOR because they use a squared ring. At least the straight
thread was easier to cut on a lathe.

Yes, but I didn't mention that because it isn't critical to the use.
If you are going to build a production machine around it, then you
machine the straight threads with the gasket pocket.

For a low-pressure one-off like this it should work fine into NPT.

-- Bruce --