O2 sensor thread

[Tom Cloud]

>The welder installed my O2 sensor adaptor but buggered up the 
>first couple of threads. I will re-tap as soon a someone can tell me

same as old-style 18 mm spark plugs -- use a plug tap or
take an old plug and make a tap out of it -- taper the first
couple of threads so it'll fit into the bung easier.  Then
cut a notch (look at a tap or re-threader)) with some relief
on the forward (CW) side.  The metal on the plug isn't hardened
like a "real" tap, so you won't be able to use it more than
once or twice, but you can make re-threading taps out of
existing items fairly easy this way.

When grinding the first few threads, don't use a grinder or file
as they leave a burr and will make it more difficult to get
the "tap" started -- use a belt or disc sander.  If you must
use a grinder, you'll probably have to take a jeweler's file
or a "threading" file to clean up the threads (Sears used
to sell the "threading" file -- it's a file with teeth cut
on the standard thread pitches .... come to think of it, it's
cut in tpi so it's not metric ... oh, well)

Tom Cloud

     The gene pool could use a little chlorine !!