Working my way round my new (to me) bungalow I am checking light switches
and wall sockets. They have all been fitted with 30mm screws (did they
used to be called bolts?) which makes them difficult to refit. I am going
to get some 40mm screws but I'd like a 3.5mm tap with handle to ensure the
threads in the sockets are OK. The bungalow as built in 1983, might the
sockets have imperial threads from then? Some of them are right pigs to
screw in.

Many thanks.

--
Jeff Gaines Dorset UK
Greater love hath no man than this, that he lay down his friends for his
life.
(Jeremy Thorpe, 1962)

On 28/04/2022 10:58, Jeff Gaines wrote:
>
> Working my way round my new (to me) bungalow I am checking light
> switches and wall sockets. They have all been fitted with 30mm screws
> (did they used to be called bolts?) which makes them difficult to refit.

Because they are not long enough or because they are damaged?

> I am going to get some 40mm screws but I'd like a 3.5mm tap with handle
> to ensure the threads in the sockets are OK. The bungalow as built in
> 1983, might the sockets have imperial threads from then? Some of them
> are right pigs to screw  in.

Electrical fittings like that tend to have the same M3.5 standard screws
in of various lengths and have done since almost forever (certainly
since 1977). Some cowboy might have forced the wrong sort of bolt in or
got one in cross threaded but you should be able to buy replacements.

The threads in the sockets are on such a small thickness of material
that you are quite likely to strip them completely bare with a tap
unless you have a very steady hand and get it exactly square on.

If you need a range of lengths it is easier to buy them as a mixed bag
since cutting a screw to length requires a bit of skill for it to remain
useable afterwards. Pair of nuts on the bit you want to keep and then
cut off the excess - but it is time consuming that way.

www.amazon.co.uk/Harlington-Group-Assorted-Electrical-Machine/dp/B08WM1FZ8X/

--
Regards,
Martin Brown

The most obvious way of differentiating between a bolt and a screw is that a
bolt is not usually threaded all the way along its shank as it has a plain
portion. A screw, however, is threaded fully to the head.

On 28/04/2022 10:58, Jeff Gaines wrote:
>
> Working my way round my new (to me) bungalow I am checking light
> switches and wall sockets. They have all been fitted with 30mm screws
> (did they used to be called bolts?) which makes them difficult to refit.
> I am going to get some 40mm screws but I'd like a 3.5mm tap with handle
> to ensure the threads in the sockets are OK. The bungalow as built in
> 1983, might the sockets have imperial threads from then? Some of them
> are right pigs to screw  in.
>
> Many thanks.
>

4BA was used in the dim and distant, retap to M3.5 is the way to go.

--
Cheers
Clive

On Thu, 28 Apr 2022 20:27:14 +1000, news.eternal-september.org
<phister@inbox.com> wrote:

> The most obvious way of differentiating between a bolt and a screw is
> that a bolt is not usually threaded all the way along its shank as it
> has a plain portion.

> A screw, however, is threaded fully to the head.

That's bullshit with most wood screws.

On 28/04/2022 10:58, Jeff Gaines wrote:
>
> Working my way round my new (to me) bungalow I am checking light
> switches and wall sockets. They have all been fitted with 30mm screws
> (did they used to be called bolts?) which makes them difficult to refit.
> I am going to get some 40mm screws but I'd like a 3.5mm tap with handle
> to ensure the threads in the sockets are OK. The bungalow as built in
> 1983, might the sockets have imperial threads from then? Some of them
> are right pigs to screw  in.
>
> Many thanks.
>

They can be a bit of a pig if you don't get the screw at right angles to
the lug in the back box. A slightly longer screw helps because it can
give some view behind the faceplate as you position the screw.

You also need some longer screws if the back box is recessed behind a
layer of plaster or tiles. If found that on the first sign of the screw
getting tight to turn immediately back it off and start again.

If you need to occasionally cut down a long M3.5 screw the tool below
works well. It's absolute shite for crimping but it has a tapped hole
for M3.5 screws. Open handle to expose the through hole, wind in the
screw, squeeze handle which cuts the screw, wind out the screw which
re-cuts the tread at the end.

https://tinyurl.com/3vjdewey

(Ebay listing of a £4 crimping tool

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 28/04/2022 11:40, Clive Arthur wrote:
> On 28/04/2022 10:58, Jeff Gaines wrote:
>>
>> Working my way round my new (to me) bungalow I am checking light
>> switches and wall sockets. They have all been fitted with 30mm screws
>> (did they used to be called bolts?) which makes them difficult to
>> refit. I am going to get some 40mm screws but I'd like a 3.5mm tap
>> with handle to ensure the threads in the sockets are OK. The bungalow
>> as built in 1983, might the sockets have imperial threads from then?
>> Some of them are right pigs to screw  in.
>>
>> Many thanks.
>
> 4BA was used in the dim and distant, retap to M3.5 is the way to go.

But long before the 1980's. I can't recall seeing BA threads on
electrical fittings at all in the past few decades.

--
Regards,
Martin Brown

alan_m wrote:

> If you need to occasionally cut down a long M3.5 screw the tool below works
> well. It's absolute shite for crimping but it has a tapped hole for M3.5 screws.
> Open handle to expose the through hole, wind in the screw, squeeze handle which
> cuts the screw, wind out the screw which re-cuts the tread at the end.
>
> https://tinyurl.com/3vjdewey

I suspect he wants the opposite, a tool to re-cut the threads in the backbox to
accept M3.5 screws

<https://uk.rs-online.com/web/p/rethreading-screwdrivers/1253090>

I daresay cheaper versions are available

On 28/04/2022 12:52, Andy Burns wrote:
> alan_m wrote:
>
>> If you need to occasionally cut down a long M3.5 screw the tool below
>> works well. It's absolute shite for crimping but it has a tapped hole
>> for M3.5 screws. Open handle to expose the through hole, wind in the
>> screw, squeeze handle which cuts the screw, wind out the screw which
>> re-cuts the tread at the end.
>>
>> https://tinyurl.com/3vjdewey
>
> I suspect he wants the opposite, a tool to re-cut the threads in the
> backbox to accept M3.5 screws

But the backboxes of that 1980's era should already be M3.5.
>
> <https://uk.rs-online.com/web/p/rethreading-screwdrivers/1253090>
>
> I daresay cheaper versions are available

--
Regards,
Martin Brown

On Thursday, 28 April 2022 at 10:58:20 UTC+1, Jeff Gaines wrote:
> Working my way round my new (to me) bungalow I am checking light switches
> and wall sockets. They have all been fitted with 30mm screws (did they
> used to be called bolts?)

Only thing I've noticed is these things tend to be called machine screws.
(Not tappered and have the thread running from head to the 'end')

'screws' seem to be tapered at the end usually for wood or plastic or called self tappers for metals .

Bolts don't have threads for the whole part of the shaft, mostly just at the end.

The above is how I describe these things to students for ordering purposes and asking
and getting what they want or think they want.

and then by lenghs in mm and M as the size M2, M2.5, M3, M4 & M5 are our standard range.

>which makes them difficult to refit. I am going
> to get some 40mm screws but I'd like a 3.5mm tap with handle to ensure the
> threads in the sockets are OK. The bungalow as built in 1983, might the
> sockets have imperial threads from then? Some of them are right pigs to
> screw in.
>
> Many thanks.
>
> --
> Jeff Gaines Dorset UK
> Greater love hath no man than this, that he lay down his friends for his
> life.
> (Jeremy Thorpe, 1962)

On 28/04/2022 10:58, Jeff Gaines wrote:
>
> Working my way round my new (to me) bungalow I am checking light
> switches and wall sockets.

Personally I recommend getting an electrician in to do an EICR. There
are many potentially dangerous faults that you won't find. Can you test
for ring continuity for example or transposed live/neutral.

> They have all been fitted with 30mm screws
> (did they used to be called bolts?) which makes them difficult to refit.
> I am going to get some 40mm screws but I'd like a 3.5mm tap with handle
> to ensure the threads in the sockets are OK. The bungalow as built in
> 1983, might the sockets have imperial threads from then? Some of them
> are right pigs to screw  in.

"Imperial Threads" were never used on "modern" wall boxes, I believe
that originally they were a 4BA thread which because it was intended for
Scientific use is a metric thread. Compare the thread pitch.

Longer bolts (to me a screw cuts its own thread) may foul the back of
the box and not tighten.

>
> Many thanks.
>

Dave

On Thursday, 28 April 2022 at 10:58:20 UTC+1, Jeff Gaines wrote:
> Working my way round my new (to me) bungalow I am checking light switches
> and wall sockets. They have all been fitted with 30mm screws (did they
> used to be called bolts?) which makes them difficult to refit. I am going
> to get some 40mm screws but I'd like a 3.5mm tap with handle to ensure the
> threads in the sockets are OK. The bungalow as built in 1983, might the
> sockets have imperial threads from then? Some of them are right pigs to
> screw in.
>
> Many thanks.

Cleaning nuts with an M3.5 tap is easy, just be sure to get it in straight or it'll trash the nut.
Imperial were used a decade before your place so I'd not expect you'd encounter it.

On 28/04/2022 in message <xn0nh5hza1gaq2u008@news.individual.net> Jeff
Gaines wrote:

>
>Working my way round my new (to me) bungalow I am checking light switches
>and wall sockets. They have all been fitted with 30mm screws (did they
>used to be called bolts?) which makes them difficult to refit. I am going
>to get some 40mm screws but I'd like a 3.5mm tap with handle to ensure the
>threads in the sockets are OK. The bungalow as built in 1983, might the
>sockets have imperial threads from then? Some of them are right pigs to
>screw in.

Many thanks for all the replies :-)

I have gone for a thread-cleaning screwdriver and a bag of mixed size M3
screws, I can use the smallest size feasible without standing on my head
with a torch in my mouth!

I certainly remember a thread before M3. Whether it was imperial or not I
don't know (my dad referred to it as such) but I remember if you did it
carefully with a decent screwdriver you could "convert" it to metric by
driving a bolt in.

--
Jeff Gaines Dorset UK
Tell me what you need, and I'll tell you how to get along without it.

In article <t4dp56$1145$1@gioia.aioe.org>,
Martin Brown <'''newspam'''@nonad.co.uk> wrote:
> On 28/04/2022 10:58, Jeff Gaines wrote:
> >
> > Working my way round my new (to me) bungalow I am checking light
> > switches and wall sockets. They have all been fitted with 30mm screws
> > (did they used to be called bolts?) which makes them difficult to refit.

> Because they are not long enough or because they are damaged?

> > I am going to get some 40mm screws but I'd like a 3.5mm tap with handle
> > to ensure the threads in the sockets are OK. The bungalow as built in
> > 1983, might the sockets have imperial threads from then? Some of them
> > are right pigs to screw in.

> Electrical fittings like that tend to have the same M3.5 standard screws
> in of various lengths and have done since almost forever (certainly
> since 1977). Some cowboy might have forced the wrong sort of bolt in or
> got one in cross threaded but you should be able to buy replacements.

They used to be 4BA before metrication

>

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On Thursday, 28 April 2022 at 14:33:04 UTC+1, Jeff Gaines wrote:
> On 28/04/2022 in message <xn0nh5hza...@news.individual.net> Jeff
> Gaines wrote:
>
> >
> >Working my way round my new (to me) bungalow I am checking light switches
> >and wall sockets. They have all been fitted with 30mm screws (did they
> >used to be called bolts?) which makes them difficult to refit. I am going
> >to get some 40mm screws but I'd like a 3.5mm tap with handle to ensure the
> >threads in the sockets are OK. The bungalow as built in 1983, might the
> >sockets have imperial threads from then? Some of them are right pigs to
> >screw in.
> Many thanks for all the replies :-)
>
> I have gone for a thread-cleaning screwdriver and a bag of mixed size M3
> screws, I can use the smallest size feasible without standing on my head
> with a torch in my mouth!
>
> I certainly remember a thread before M3. Whether it was imperial or not I
> don't know (my dad referred to it as such) but I remember if you did it
> carefully with a decent screwdriver you could "convert" it to metric by
> driving a bolt in.

As well as BA screws, the double MK sockets from early 70s had 4 screw fixing not 2, so while they look like modern sockets & boxes they're not really compatible.

On 28/04/2022 14:29, charles wrote:
> In article <t4dp56$1145$1@gioia.aioe.org>,
> Martin Brown <'''newspam'''@nonad.co.uk> wrote:
>> On 28/04/2022 10:58, Jeff Gaines wrote:
>>>
>>> Working my way round my new (to me) bungalow I am checking light
>>> switches and wall sockets. They have all been fitted with 30mm screws
>>> (did they used to be called bolts?) which makes them difficult to refit.
>
>> Because they are not long enough or because they are damaged?
>
>>> I am going to get some 40mm screws but I'd like a 3.5mm tap with handle
>>> to ensure the threads in the sockets are OK. The bungalow as built in
>>> 1983, might the sockets have imperial threads from then? Some of them
>>> are right pigs to screw in.
>
>> Electrical fittings like that tend to have the same M3.5 standard screws
>> in of various lengths and have done since almost forever (certainly
>> since 1977). Some cowboy might have forced the wrong sort of bolt in or
>> got one in cross threaded but you should be able to buy replacements.
>
> They used to be 4BA before metrication

But it was all over bar the shouting by 1975 so it is very unlikely that
a home built in the 1980's would have any such parts installed. My house
extension was in 1975 and there is no trace of pre metric components.

The last time I saw BA threads in electrical installations was somewhere
that hadn't been rewired since the 1950's and still had a selection of
scary round pin partly broken Bakelite plugs and sockets in daily use.

--
Regards,
Martin Brown

On Thursday, April 28, 2022 at 10:58:20 AM UTC+1, Jeff Gaines wrote:
> Working my way round my new (to me) bungalow I am checking light switches
> and wall sockets. They have all been fitted with 30mm screws (did they
> used to be called bolts?) which makes them difficult to refit. I am going
> to get some 40mm screws but I'd like a 3.5mm tap with handle to ensure the
> threads in the sockets are OK. The bungalow as built in 1983, might the
> sockets have imperial threads from then? Some of them are right pigs to
> screw in.
>
> Many thanks.
>
> --
> Jeff Gaines Dorset UK
> Greater love hath no man than this, that he lay down his friends for his
> life.
> (Jeremy Thorpe, 1962)

I have used one of these to restore threads in various back boxes and it has done a good job so far. One or two of the very badly raunched ones have been a bit sloppy after rethreading but all so far have screwed up tight and held OK.

https://www.screwfix.com/p/c-k-re-threading-tool-m3-5-x-0-6mm/59312

Richard

On 28/04/2022 14:58, Martin Brown wrote:
> On 28/04/2022 14:29, charles wrote:
>> In article <t4dp56$1145$1@gioia.aioe.org>,
>>     Martin Brown <'''newspam'''@nonad.co.uk> wrote:
>>> On 28/04/2022 10:58, Jeff Gaines wrote:
>>>>
>>>> Working my way round my new (to me) bungalow I am checking light
>>>> switches and wall sockets. They have all been fitted with 30mm screws
>>>> (did they used to be called bolts?) which makes them difficult to
>>>> refit.
>>
>>> Because they are not long enough or because they are damaged?
>>
>>>> I am going to get some 40mm screws but I'd like a 3.5mm tap with handle
>>>> to ensure the threads in the sockets are OK. The bungalow as built in
>>>> 1983, might the sockets have imperial threads from then? Some of them
>>>> are right pigs to screw  in.
>>
>>> Electrical fittings like that tend to have the same M3.5 standard screws
>>> in of various lengths and have done since almost forever (certainly
>>> since 1977). Some cowboy might have forced the wrong sort of bolt in or
>>> got one in cross threaded but you should be able to buy replacements.
>>
>> They used to be 4BA before metrication
>
> But it was all over bar the shouting by 1975 so it is very unlikely that
> a home built in the 1980's would have any such parts installed. My house
> extension was in 1975 and there is no trace of pre metric components.
>
> The last time I saw BA threads in electrical installations was somewhere
> that hadn't been rewired since the 1950's and still had a selection of
> scary round pin partly broken Bakelite plugs and sockets in daily use.
>

They changed to M3.5 in the late 1960's. Some switches and sockets came
with both 4BA and M3.5 screws for a while

On 28/04/2022 16:57, ARW wrote:
> On 28/04/2022 14:58, Martin Brown wrote:
>> On 28/04/2022 14:29, charles wrote:
>>> In article <t4dp56$1145$1@gioia.aioe.org>,
>>>     Martin Brown <'''newspam'''@nonad.co.uk> wrote:
>>>> On 28/04/2022 10:58, Jeff Gaines wrote:
>>>>>
>>>>> Working my way round my new (to me) bungalow I am checking light
>>>>> switches and wall sockets. They have all been fitted with 30mm screws
>>>>> (did they used to be called bolts?) which makes them difficult to
>>>>> refit.
>>>
>>>> Because they are not long enough or because they are damaged?
>>>
>>>>> I am going to get some 40mm screws but I'd like a 3.5mm tap with
>>>>> handle
>>>>> to ensure the threads in the sockets are OK. The bungalow as built in
>>>>> 1983, might the sockets have imperial threads from then? Some of them
>>>>> are right pigs to screw  in.
>>>
>>>> Electrical fittings like that tend to have the same M3.5 standard
>>>> screws
>>>> in of various lengths and have done since almost forever (certainly
>>>> since 1977). Some cowboy might have forced the wrong sort of bolt in or
>>>> got one in cross threaded but you should be able to buy replacements.
>>>
>>> They used to be 4BA before metrication
>>
>> But it was all over bar the shouting by 1975 so it is very unlikely
>> that a home built in the 1980's would have any such parts installed.
>> My house extension was in 1975 and there is no trace of pre metric
>> components.
>>
>> in daily use.
>>
>
> They changed to M3.5 in the late 1960's.  Some switches and sockets came
> with both 4BA and M3.5 screws for a while

My house, bought new in 1971, had all sockets with 4BA screws.

"Jeff Gaines" <jgaines_newsid@yahoo.co.uk> wrote in message
news:xn0nh5hza1gaq2u008@news.individual.net...
>
> Working my way round my new (to me) bungalow I am checking light switches
> and wall sockets. They have all been fitted with 30mm screws (did they
> used to be called bolts?) which makes them difficult to refit. I am going
> to get some 40mm screws but I'd like a 3.5mm tap with handle to ensure the
> threads in the sockets are OK. The bungalow as built in 1983, might the
> sockets have imperial threads from then? Some of them are right pigs to
> screw in.
>
>

In addition to all the previous posts you can get replacement 3.5mm screws
that have a plain, non threaded, end. This allows easy alignment of the
screw & helps to prevent cross threading.
e.g.
-
https://www.cef.co.uk/catalogue/categories/screws-m3-5-machine-electrical-sockets

--
Regards
wasbit

On 29/04/2022 09:45, wasbit wrote:
> "Jeff Gaines" <jgaines_newsid@yahoo.co.uk> wrote in message
> news:xn0nh5hza1gaq2u008@news.individual.net...
>>
>> Working my way round my new (to me) bungalow I am checking light
>> switches and wall sockets. They have all been fitted with 30mm screws
>> (did they used to be called bolts?) which makes them difficult to
>> refit. I am going to get some 40mm screws but I'd like a 3.5mm tap
>> with handle to ensure the threads in the sockets are OK. The bungalow
>> as built in 1983, might the sockets have imperial threads from then?
>> Some of them are right pigs to screw  in.
>>
>>
>
> In addition to all the previous posts you can get  replacement 3.5mm
> screws that have a plain, non threaded, end. This allows easy alignment
> of the screw & helps to prevent cross threading.
> e.g.
> -
> https://www.cef.co.uk/catalogue/categories/screws-m3-5-machine-electrical-sockets
>
>

I agree, those type do help a lot but it is still possible to cross
thread them.

Another tip - if the back box was in the wall while the wall was being
plastered it is possible that a little plaster ends up (partially)
blocking the threaded hole in the back box lug. Clean out the hole by
poking a nail into it and before trying to put a faceplate/socket/switch
on try one of the screws in the back box lug. It can save a lot of
hassle :)

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

Why are 99.9% of the M3.5 supplied with socket and switches slotted
headed rather a cross head? I've only purchased one (no-name) brand
with cross head screws.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 29/04/2022 10:43, alan_m wrote:
>
> Why are 99.9% of the M3.5 supplied with socket and switches slotted
> headed rather a cross head?  I've only purchased one (no-name) brand
> with cross head screws.

Because electricians screwdrivers have always been "-" type.

You do sometimes see the odd cross head screw forced into one.

--
Regards,
Martin Brown

Martin Brown wrote:

> alan_m wrote:
>
>> Why are 99.9% of the M3.5 supplied with socket and switches slotted headed
>> rather a cross head?
>
> Because electricians screwdrivers have always been "-" type.
> You do sometimes see the odd cross head screw forced into one.

Some newer BT faceplates use "woodscrews" rather than machine screws, they're
crosshead and just look wrong.

On Thu, 28 Apr 2022 20:41:47 +1000, Jock wrote:

> On Thu, 28 Apr 2022 20:27:14 +1000, news.eternal-september.org
> <phister@inbox.com> wrote:
>
>> The most obvious way of differentiating between a bolt and a screw is
>> that a bolt is not usually threaded all the way along its shank as it
>> has a plain portion.
>
>> A screw, however, is threaded fully to the head.
>
> That's bullshit with most wood screws.

Don't be silly.