At 07:26 PM 2/2/03 -0600, MonteMorris wrote:
>.... I was at Sears today and looked at tap and dies sets. .... I saw
>mostly metric and standard sets, but aren't most of the MG bolts SAE (is
>this fine threaded?)? I'm not real sure what that even means, but I know
>that I never have a nut around the shop that will fit anything on the MGs. ....
SAE = Society of Automotive Engineers. The SAE standard threads are in
general fine threaded screws, and they are almost exactly the same as UNF
(Unified National Fine), with the nuts and bolts being genarally
interchangeable. SAE threads could be either inch or metric
dimensions. However, for your MGB these are nearly all standard inch
dimension fasteners, not metric.
There are a few exceptions, such as a few carburetor screws, the windscreen
frame, maybe the wiper motor or an original fuel pump, mostly sloted head
screws, and maybe thumb nuts holding instruments in the dash with a
slightly odd thread pitch. And I suppose others will mention a few more
odd ones. These odd ones are most often British Standard Fine with inch
dimensions but "other" thread pitch. I don't know if there are any older
Whitworth standard fasteners on the MGB, but surely not enough to worry
about. I have an MGA, and I have no Whitworth tools in my posession (and
never a need as far as I know).
You should be aware that most of the cross slotted screws on the MG which
may appear to have Phillips slots are actually PosiDrive screws, and the
screwdriver bits are significantly different in function (but hard to tell
apart visually. Basically the Posidrive screws have straight sided slots
which will hold the proper driver bit very securely. Phillips screws and
driver bits have tapered slots so the driver bits are designed to cam out
of the slots at a certain torque for ease od production.
For servicing your MG it would be good if you bought a full set of inch
series taps and dies, particularly the fine threaded ones. You may find
inch dimension coarse threads on non-automotive things around the
home. Most cars built after 1980 have at least some metric
fasteners. Most American cars now have metric fasteners in engines and
transmissions, but sometimes still use inch size fasteners for accessory
parts like alternator and air conditioner mounts.
Barney Gaylord
1958 MGA with an attitude
http://MGAguru.com
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