Plenty of people have pointed out that the best answer is a 1/4"-20 nut. If
you really can't find this size nut, you might be able to make a fastener.
How heavy is the attachment, and how secure does it have to be? If it's not
too heavy, you might be able to make your own fastener by doing this:
-Get a small piece of fairly strong plastic (unfilled nylon, PET, PBT...not
an acrylic or epoxy)...maybe one of those little protectors that goes on an
exposed screw thread on a bicycle so you don't cut yourself or snag your
clothes. Perhaps you could use a plastic spacer or standoff;
-Drill a hole in the plastic. The hole size should be just at or slightly
larger than the "minor diameter" of the screw (i.e., the diameter at the
bottom of the threads). You can "eyeball" that by holding the drill bit
behind the screw;
-Using a pliers or Vice-Grips, hold the plastic, and screw it onto the
tripod screw. The metal screw will cut and form the threads into the
plastic. If it's too difficult to turn the plastic, re-drill the hole a
little larger. The metal screw will form the threads partially by cutting
the plastic, and partially by forcing some of the plastic into shape--that's
why you can get away with drilling the hole a little over-sized.

In a pinch, you might find a plastic metric-sized nut with a hole of
*almost* the correct diameter, and force it over the screw so that new
threads are formed. I think these are usually nylon. Check your local Radio
Shack (you might call them "Tandy") or hardware store.

Other sources of 1/4"-20 fasteners might be old American-made items that
people have stored away...something like an old radio or toy. (More recent
ones were probably made in Korea or China, and it's a crap-shoot whether
they'd have inch or metric fasteners.)

Oddly, with screws and nuts that as sized as fractions of an inch, we refer
to them as "English." Since metric screws are sized by how many mm each
thread is separated, the equivalent of 20 threads per inch is a pitch of
1.27 mm, and a 1/4" diameter is 6.35 mm. Maybe that info will help you find
a nylon nut in a close size, as suggested above.


"Andy" wrote in message
...
I am in the UK and I have a minature tripod for a 35mm camera.

I want to attach something else to the tripod using the threaded bolt on
the tripod which normally goes into the body of the camera.

That bolt is about 1/4inch across and I have read that it has 20 threads
per inch, so it gets to be called "1/4-20".

I want a nut to fit this.

QUESTION: What would be the reference or specification for the correct
nut?

ISTR this threaded bolt is a slightly unusual size in Europe.

QUESTION: Can I get a bush to fit over the screwed bolt in order to be
able to get a more widley available nut?

QUESTION: Is there a common nut size (as far as Europe goes) which
might fit a bit loosely on the bolt but which could still be tightened?