Louis Ohland wrote:
Major dia is 15.6mm

Geez, what's wrong with a pint's a pound the word around?

Because it isn't, see http://en.wikipedia.org/wiki/Pint


On 2/24/2011 17:43, David Billington wrote:
Louis Ohland wrote:
I got a partial fit with an 18 TPI leaf, they fit fairly close over
the length, but the depth is wrong, the teeth of the leaf won't go
down very far into the thread.

The corresponding BSP thread would be 19 tpi and 55 degree thread form
rather than 60 degree which may explain the mismatch. While not ideal I
think you posted that this was a coolant connection, if that is the case
then all you really need to do is seal it and that can be done with PTFE
tape or one of the many thread sealing compounds available for the
purpose.
On 2/24/2011 17:25, David Billington wrote:
Louis Ohland wrote:
Preparing to run coolant on my X3, I pulled the coolant plug out,
expecting an NPT thread. It isn't. It's a straight thread, Major
diameter is @ .620, pitch diameter is @ .577.

The Grizzly manual does not even show the plug, which is at the far
left rear corner.

Anyone with the answer?
Have you checked the TPI, it's possible what you have is a metric pipe
thread, which is actually a metricated BSP thread, and comes in
straight
or tapered depending on use. I can't find my copy of Machinery's at
the
moment to look up the details.

Seems to me that the US is being metricated by stealth as when I lived
in the US almost 30 years ago you couldn't find metric whatever in the
local hardware store but now it's mentioned as common place on RCMW.