> Now the proposal: Randall has posted a list of unusual threads for TR3A
> before, though unfortunately I don't have it.
Apparently, neither do I. Seems like I should have saved it, but can't find
it at the moment. And, having not touched my TR3A for a year now, the
memory is fading.
> I'm sure others have knowledge
> and perhaps have documented a number of different screw sizes and threads.
The best document is the factory Spare Parts Catalog. Most of the
bolts/screws are assigned a "standard" number, that can be decoded to
determine thread diameter and pitch, length, head style, etc. These numbers
start with two letters which determine the fastener style (eg Philips screw,
hex bolt, etc.), then a 3 or 4 digit number. The last two digits give the
length (in 1/16" increments) while the first one or two digits give
information about the thread diameter and pitch, plus (sometimes) head style
within the fastener style.
There is a "magic decoder ring" for the standard hardware numbers. known as
the Standard Triumph Hardware Catalog. Some kind person (sorry, I've
forgotten who) has scanned this very useful document and the scans are
available in several places, including
http://tidentenn.com/cars/tr4.htm
I strongly suggest you find the link to the catalog (scroll down about 2/3)
and download it to your hard drive. It's only about 2Mb, but it's painful
to look at it on-line. Unfortunately it's not text-searchable, so you'll
have to scroll through the document to find the part number you want. I've
been slowly adding a table of contents to my copy, since I have Acrobat at
work.
A good thread gauge (hardware store), cheap dial calipers (Enco), an eye
loupe (Harbor Freight), and the charts on the following page will go a long
way towards identifying "mystery" threads. I keep the chart taped to the
wall in my garage for easy reference.
http://mdmetric.com/tech/tict.htm
Randall
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