In a message dated 12/29/98 11:47:41 AM Eastern Standard Time,
MPRICE@KeystoneSystems.com writes:
> 1) I understand that the threads on these fasteners are a british fine
> thread or something like that. Is this the same as National Fine Threads
> we see here in the US?
> 2)I've seen many letter combinations thrown around, and other than Pipe
> Threads (NPT?), and Standard (NST?), I haven't a clue as to what they
> all are. For the fasteners on my car, what am I looking for? BFT?
Mark,
The threads are UNF (Unified National Fine, I think that stands for), and are
the same standard as used here in America. For the most part, American cars
use UNC -Unified National Course. UNF threads are a little bit stronger than
UNC, because the root diameter of the bolt is not as small for a given size.
NPT stands for National Pipe Taper, I believe. It is a tapered thread, and is
usually used for plumbing - being tapered, the fit gets tighter as you torque
it down, helping to seal for a liquid tight joint. A few fasteners are NPT in
a car, usually brake fittings, gas lines, or water connections.
> 3)Is there a readily available source for these fasteners other than the
> big 3? I can't imagine that my local Ace Hardware stocks these, and I
> don't know all the sizes I'm going to need. ("Yup, gonna need 4 just
> like this old rusty one here.")
Look in the Yellow Pages for a fastener shop in your town. In the small town
of Alcoa, we have at least two, and they both carry a LARGE selection of UNF
fasteners (and all sorts of other specialty fasteners as well - be prepared to
spend a good little while just browsing. You'll find oddball fasteners and
such that will make you want to go home and make something just to use them!),
and sell them by the pound (about $4/pound for grade five, regardless of size.
Grade eight fasteners are sold at a per piece price, but you don't need many
of them). I bought $100 dollars worth a while back, and I haven't needed to go
back yet for a size that is missing. I just went through the bins, grabbing a
handful of this size, and a handful of that size, till I had all that I though
I would ever need - about 25 pounds of fasteners!
There are a few fasteners in a TR6 that are NOT standard UNF, even though the
threads are the same. An example of this is the bolts that hold the rotors to
the hubs. Below a certain length, standard bolts are threaded the full length,
while longer bolts have an unthreaded shank for part of the length. The rotor
bolts are too short to have the unthreaded shank in the standard
configuration, but the they need that to precisely locate the rotor, as the
rotor must be concentric with the hub.
> 4)Taps and Dies for these? Where is a good source for these?
I have a set of Craftsman; one side of the box has UNC, and the other side has
UNF.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/index.html
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
|