Triumphisti,
About a month ago we were talking about greasing/oiling the TR6 and
250 steering racks. If you recall, we discussed that the plug at the top of
the pinion cap is 1/8 BSP (British Standard Pipe) which is a 28 thread per
inch parallel pipe thread. Commonly available US grease nipples are 1/8
"pipe thread", which is a tapered thread with 27 tpi. The US grease nipple
or a standard US grease gun hose (same thread, at least on my grease gun)
can be "made" to fit by jamming the different threads together, which
essentially taps the pinion cap enough to hold while the grease or oil is
applied. This "works", so if you're happy with that the rest of my post is
fluff. Please disregard.
I've found that Stewart-Warner makes a 2-piece adaptor kit for
their instruments that includes a 1/8 BSP male to 1/8 US pipe thread female
adaptor. This allows you to put the grease fitting into the adaptor, then
put the adaptor into the steering rack, and not damage any threads. As a
bonus, you can leave it permanently installed, because the adaptor will
hold the ground wire for the horn in place. The only drawback is that in my
steering rack, the adaptor's slightly longer threaded portion fouls the
pinion gear when fully screwed down, so I have to put a spacer washer
between the horn ground ring and the adaptor's shoulder.
For anyone interested, you want item number 1073 from Pegasus Auto
Racing Supplies, 1-800-688-6946. It lists for $12.49, and you also get the
"opposite" adaptor (1/8 pipe thread male to 1/8 BSP female), for which I've
yet to identify a purpose. The Stewart-Warner part number on the box is
82561-F. It's not cheap, I admit, but I think intentionally mangling
threads is bad karma.
Best Regards,
Tom Marincic
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