BA screws

[truegridtz]

This is about British Association screws. Anybody know of a source for
these?

These were declared obsolete in the early or mid 60s. The Brits had their
own thread pitch for their smallest metric screws.

These were used in Garrard and Collaro (Magnavox) changers. The thread
pitches are in inches and the diameters are in mm. The diameters are not
standard metric.

The only BA screw that matches anything recognized today is the BA 6 that
has 47.9 threads per inch. This matches a 3-48 except that the BA6 is a few
thousands larger in diameter. The 3-48 will work but there is reduced
thread contact.

Other thread pitches are BA4 with 38.5 tpi. and BA3 with 34.8 tpi. The
smallest is BA16 with 134 tpi (.79mm diameter). The diameter of the BA4 is
3.6mm..

All I found on the web was some guy that sells Garrard headshell kits and
these are probably just 3-48. I have plenty BA6 anyhow.

Does anyone know of a source for BA screws (other than scrapping a changer)?
I have never needed a BA3 or BA4, but in the event I ever do it would be
nice to know where to get them. Mark

[Martin]

Post by truegridtz
This is about British Association screws. Anybody know of a source for
these?
These were declared obsolete in the early or mid 60s. The Brits had their
own thread pitch for their smallest metric screws.
These were used in Garrard and Collaro (Magnavox) changers. The thread
pitches are in inches and the diameters are in mm. The diameters are not
standard metric.
The only BA screw that matches anything recognized today is the BA 6 that
has 47.9 threads per inch. This matches a 3-48 except that the BA6 is a few
thousands larger in diameter. The 3-48 will work but there is reduced
thread contact.
Other thread pitches are BA4 with 38.5 tpi. and BA3 with 34.8 tpi. The
smallest is BA16 with 134 tpi (.79mm diameter). The diameter of the BA4 is
3.6mm..
All I found on the web was some guy that sells Garrard headshell kits and
these are probably just 3-48. I have plenty BA6 anyhow.
Does anyone know of a source for BA screws (other than scrapping a changer)?
I have never needed a BA3 or BA4, but in the event I ever do it would be
nice to know where to get them. Mark

http://www.jacrew.net/
has a wide selection, and lots more useful odd bits.
There is a minimum postage charge of 3 pounds sterling,
but they take credit cards.
HTH,
Martin(Stockport)

["Haggis" telus.net>]

On 27-Feb-2005, "truegridtz" <***@hal-pc.org> wrote:

< This is about British Association screws. Anybody know of a source for
these?>

Presuming you're in the US, have you tried British Tools & Fasteners in NY?
(http://www.britishfasteners.com?)
I know nothing more about them other than they list a good assortment in the
catalog.

Haggis ( a major user of BA screws, who usually has to make his own :-))

[truegridtz]

Post by "Haggis" telus.net>
< This is about British Association screws. Anybody know of a source for
these?>
Presuming you're in the US, have you tried British Tools & Fasteners in NY?
(http://www.britishfasteners.com?)
I know nothing more about them other than they list a good assortment in the
catalog.
Haggis ( a major user of BA screws, who usually has to make his own :-))

Thanks for the great link. They do have BA screws and taps and dies. What
are they used for these days, or are you repairing vintage machines? Mark

[truegridtz]

Just in case you're interested this is a quote from the British fastener
site. If you want something from Britain this is the place to look.

"BA (British Association) Thread Data

This thread has been around for a long time. It was first formulated in 1884
and was standardised in 1903. Mainly found in electrical fittings and
accessories, it is slowly being replaced by ISO metric."

http://www.britishfasteners.com/threads/index.html

This is the chart for all of the BA thread data. Mark

["Haggis" telus.net>]

Post by "Haggis" telus.net>
Haggis ( a major user of BA screws, who usually has to make his own :-))

<Thanks for the great link. They do have BA screws and taps and dies.
What are they used for these days, or are you repairing vintage machines?
Mark.>


To the best of my knowledge Mark, BA threads are not used for anything
except "vintage" and "antique" stuff these days. I bought BA taps and dies
about 40 years ago, when I was into building model engines. Most all
modelling plans in Canada came from the UK "back then". Since becoming
interested in old crystal sets, my collection has been almost exlusively
British sets and the odd nut and bolt I need (never a pair, of course :-))
is in BA thread. Murphy says that the one size needed is the one which got
lost or broken, but one of our regular contributors on the group has kindly
picked me up replacements in Canada, unfortuanately 3000 Km. from where I
live. Drop me a line if I can help in any other way.
Haggis.

[william_b_noble]

if these are the screws that hold cartriges to headshells, I have a small
pile of them, let me know, if not, then I probably can't help

Post by truegridtz
This is about British Association screws. Anybody know of a source for
these?
These were declared obsolete in the early or mid 60s. The Brits had their
own thread pitch for their smallest metric screws.
These were used in Garrard and Collaro (Magnavox) changers. The thread
pitches are in inches and the diameters are in mm. The diameters are not
standard metric.
The only BA screw that matches anything recognized today is the BA 6 that
has 47.9 threads per inch. This matches a 3-48 except that the BA6 is a few
thousands larger in diameter. The 3-48 will work but there is reduced
thread contact.
Other thread pitches are BA4 with 38.5 tpi. and BA3 with 34.8 tpi. The
smallest is BA16 with 134 tpi (.79mm diameter). The diameter of the BA4 is
3.6mm..
All I found on the web was some guy that sells Garrard headshell kits and
these are probably just 3-48. I have plenty BA6 anyhow.
Does anyone know of a source for BA screws (other than scrapping a changer)?
I have never needed a BA3 or BA4, but in the event I ever do it would be
nice to know where to get them. Mark

[Jim Adney]

Post by truegridtz
This is about British Association screws. Anybody know of a source for
these?
These were declared obsolete in the early or mid 60s. The Brits had their
own thread pitch for their smallest metric screws.

They might be obsolete, but I think they are still in use in some
places. I had to buy Jackson Bros. variable caps for work maybe 10
years ago and I was informed that the tapped holes in them were BA
standard. I didn't know how to buy BA screws, so I asked them to ship
the caps with screws installed. They agreed.

-
-----------------------------------------------
Jim Adney ***@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

[Bill Turner]

ALL JACKSON BROTHERS CAPACITORS COME WITH SCREWS ATTACHED, AT LEAST ALL
I ORDER HAVE. THIS IS 410 uuF SINGLE AND DUAL TYPES.


CHECK MY WEBSITE: www.dialcover.com
Bill Turner, excuse caps, short answers, stroke.
Business SASE, each order a copy of The Pocket Resource Guide.

[truegridtz]

There is a 100 piece assortment at the British fastener company in NY for
$20, sizes 5,4,3,2,1,0. No telling where a BA screw may turn up. From the
descriptions given here they were very common in the past.

The following are extracts from the website
http://www.sizes.com/tools/thread_BA.htm.

I was trying to figure out why the BA thread pitches are so strange. The
reason given in the following extract is not clear except that it says
that BA pitches are some sort of metric ratio. The question is why did they
list them in TPI?

(extract begins here)
"In 1884 the British Association for the Advancement of Science adopted a
thread form and series, primarily for use in precision equipment. It was
inspired by one used in the Swiss watch and clock industry, and was formerly
sometimes called the Swiss Small Screw Thread System; but is now just
referred to as the BA series. Like the Whitworth thread, it has a rounded
root and crest, but the included angle is 47.5° and the radius was
originally 2/11 (0.1818.) times the pitch, but at some later point was
changed to 0.18083.


Despite the date of origin and the British sponsorship, the BA is a metric
series. Not only is it based on the meter, but the thread frequency is
specified in terms of round numbers in the pitch sequence, with threads per
meter allowed to fall where it may.

The British Association thread played a role similar to that of the ASME
series in the United States, that is, it filled in sizes below a
quarter-inch. The sizes most used were the even-numbered ones between 0 and
10, inclusive. The very small sizes, from 17 up, were rarely used. The
British Standards Institution (BSI) discouraged the use of #0 BA in favor of
the 7?32? BSF.


In 1966 the BSI declared the BA screw thread obsolete; its place was taken
by ISO screw threads." (end of quote)

For those who may not know, ISO is the International
Standards Organization. I recall that Nissan automotive screws went to ISO
in the very early 70s. I had a 68 Datsun 2000 which had two different
metric pitches and also SAE in the frame and brakes. Before ISO there were
several different metric pitches worldwide.

Hmmm, mabey the Brits were into TPI with the Whitworth and converted the
Swiss pitches to their own machinist language.

Thanks for all the help, guys. I had no idea I would find this much. Mark