On Sun, 24 Aug 2003 16:24:50 -0700, Stu wrote:

Has anybody had any experience with the ADC chip detector? Mine has been
installed in a casting which had a 3/4" long hole tapped to 3/8-18 NPT.
The threads on the Chip Detector appear to be straight rather than tapered
and only have about 3.5 thds to engage the casting thds. When tightening
ever so lightly, the detector #1 leaks and if tightened much more it seems
to strip a small amount of thread from the casting. Micrometer
measurements indicate the detector is smaller than a 3/8-18 pipe plug. Stu
Fields

All the boss threads in the installations I have experience with have been
straight threaded. The chip detectors used o-rings for sealing and we
replaced them almost every year. I cant see a tapered thread (NPT) being a
good plan because the threads are upset to provide a seal and would very
quikly, three or four install and removals, require some sort of repair.
A pipe thread has a long lead portion so you can turn it in until it
seals, I imagine the chip detector you have has a flange that limits the
depth it can be turned in.

How far does the boss protrude from the casting? You may be able to mill
the face down far enough to get enough material to cut straight threads
and put a chamfer for your o-ring. See MS33649 for the correct thread and
chamfer size, google for that in .pdf format.

Hope that helps,

Mike
Crewchief
Me262 Project LLC

Remove NOT to get me.