I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight). The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly out
of line. There weren't any screws supplied but it looks like it needs
a screw with a narrow shank for the first 5mm from the head. It
should be simple, in principle, to stroke the threads from a spare
screw using a file but it needs to be held tight while filing and
clamping it in a vice will just wreck the working part of the thread.
If it was any other size, I would put a couple of nuts on it, but
electrical screws are 'special' and nobody sells that size nut (M3 and
M4, ok, but not M3.5).
So....How would you resourceful people do it? I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to end
up with a screw that won't go into the box because I've cream-
crackered the thread.

"GMM" wrote in message
...
I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight). The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly out
of line. There weren't any screws supplied but it looks like it needs
a screw with a narrow shank for the first 5mm from the head. It
should be simple, in principle, to stroke the threads from a spare
screw using a file but it needs to be held tight while filing and
clamping it in a vice will just wreck the working part of the thread.
If it was any other size, I would put a couple of nuts on it, but
electrical screws are 'special' and nobody sells that size nut (M3 and
M4, ok, but not M3.5).
So....How would you resourceful people do it? I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to end
up with a screw that won't go into the box because I've cream-
crackered the thread.

Could you screw it into a wallplug and hold the plug in the vice?
Unscrew or cut the plug off when filing completed.

I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight). The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly out
of line. There weren't any screws supplied but it looks like it needs
a screw with a narrow shank for the first 5mm from the head. It
should be simple, in principle, to stroke the threads from a spare
screw using a file but it needs to be held tight while filing and
clamping it in a vice will just wreck the working part of the thread.
If it was any other size, I would put a couple of nuts on it, but
electrical screws are 'special' and nobody sells that size nut (M3 and
M4, ok, but not M3.5).
So....How would you resourceful people do it? I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to end
up with a screw that won't go into the box because I've cream-
crackered the thread.

At the size mentioned the actual thread pitch won't be that different from
the next size up (M4)
Cut an M4 nut in half using a junior hacksaw and use the two halves as a
support in the vice wit the original screw between them.

GMM expressed precisely :
I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight). The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly out
of line. There weren't any screws supplied but it looks like it needs
a screw with a narrow shank for the first 5mm from the head. It
should be simple, in principle, to stroke the threads from a spare
screw using a file but it needs to be held tight while filing and
clamping it in a vice will just wreck the working part of the thread.
If it was any other size, I would put a couple of nuts on it, but
electrical screws are 'special' and nobody sells that size nut (M3 and
M4, ok, but not M3.5).
So....How would you resourceful people do it? I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to end
up with a screw that won't go into the box because I've cream-
crackered the thread.

Put the screw thread end into the chuck of a drill, tighten then start
the drill. Use a file against the thread to turn the thread down a
little. It will not damage the threads unless it slips in the chuck.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

"GMM" wrote in message
...
I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight). The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly out
of line. There weren't any screws supplied but it looks like it needs
a screw with a narrow shank for the first 5mm from the head. It
should be simple, in principle, to stroke the threads from a spare
screw using a file but it needs to be held tight while filing and
clamping it in a vice will just wreck the working part of the thread.
If it was any other size, I would put a couple of nuts on it, but
electrical screws are 'special' and nobody sells that size nut (M3 and
M4, ok, but not M3.5).
So....How would you resourceful people do it? I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to end
up with a screw that won't go into the box because I've cream-
crackered the thread.

Buy a couple of screw longer than you need, clamp the end in a vice, file
down what you need to and then cut off the threads knackered by the vice to
leave you with the correct length screw.

Adam

On Wed, 29 Oct 2008 10:05:52 -0700 (PDT), GMM wrote:

I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight). The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly out
of line. There weren't any screws supplied but it looks like it needs
a screw with a narrow shank for the first 5mm from the head.

Was this a new purchase, or something you've acquired? Very surprised there
weren't any screws enclosed.

Have you tried a 'phone call to the manufacturer or electrical wholesaler?
If it came from a shed, take it back and ask for a replacement with screws.
Sadly, it's a fact of life that stuff gets opened in the sheds so that all
the novices can take a gander to see what it's all about, and bits go
missing or get damaged. Oh, FWIW, I always open stuff like that when I'm
buying from a shed, but that's only to make sure everything's there that
should be there.


--
Si Hoc Legere Scis Nimium Eruditionis Habes

the dot wanderer at tesco dot net

On Wed, 29 Oct 2008 10:05:52 -0700, GMM wrote:

I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight). The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly out
of line. There weren't any screws supplied but it looks like it needs
a screw with a narrow shank for the first 5mm from the head. It
should be simple, in principle, to stroke the threads from a spare
screw using a file but it needs to be held tight while filing and
clamping it in a vice will just wreck the working part of the thread.
If it was any other size, I would put a couple of nuts on it, but
electrical screws are 'special' and nobody sells that size nut (M3 and
M4, ok, but not M3.5).
So....How would you resourceful people do it? I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to end
up with a screw that won't go into the box because I've cream-
crackered the thread.

==========================================
If you have enough length to work with clamp the screw at 45 degrees in
one side of the vice jaws so that the screw is held mid way between head
and working end. Use a small 'rat tail' file or a riffler to do the filing.

Cic.

--
==========================================
Using Ubuntu Linux
Windows shown the door
==========================================

RW wrote:

I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight). The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly out
of line. There weren't any screws supplied but it looks like it needs
a screw with a narrow shank for the first 5mm from the head. It
should be simple, in principle, to stroke the threads from a spare
screw using a file but it needs to be held tight while filing and
clamping it in a vice will just wreck the working part of the thread.
If it was any other size, I would put a couple of nuts on it, but
electrical screws are 'special' and nobody sells that size nut (M3 and
M4, ok, but not M3.5).
So....How would you resourceful people do it? I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to end
up with a screw that won't go into the box because I've cream-
crackered the thread.


At the size mentioned the actual thread pitch won't be that different from
the next size up (M4)
Cut an M4 nut in half using a junior hacksaw and use the two halves as a
support in the vice wit the original screw between them.

Or use a piece of wood and drill the right size hole in it to allow the
screw to be pushed in with a bit of force. Now, using as fine a saw as
you can find, make a saw cut down the wood so that it cuts the hole into
two sides. Put the screw in and clamp in a vice to file the screw.

Dave

In message
, GMM
writes

So....How would you resourceful people do it? I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to end
up with a screw that won't go into the box because I've cream-
crackered the thread.

Use a bit of soft aluminium between the vice jaws and the screw thread.

regards

--
Tim Lamb

"GMM" wrote in message
...
I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through
for
each screw, it has a curved 'keyhole' shaped slot (presumably to
allow
a bit of rotation to get it nice and straight). The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly
out
of line. There weren't any screws supplied but it looks like it
needs
a screw with a narrow shank for the first 5mm from the head. It
should be simple, in principle, to stroke the threads from a spare
screw using a file but it needs to be held tight while filing and
clamping it in a vice will just wreck the working part of the
thread.
If it was any other size, I would put a couple of nuts on it, but
electrical screws are 'special' and nobody sells that size nut (M3
and
M4, ok, but not M3.5).
So....How would you resourceful people do it? I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to
end
up with a screw that won't go into the box because I've cream-
crackered the thread.

Grip in vice using 'soft jaws'. Two bits of aluminium angle, or a bit
of bent lead.

AWEM

On Oct 29, 5:05*pm, GMM wrote:
I have this heating controller to wire up and screw onto a standard
electrical back box. *Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight). *The wide end of the
slot take a standard 3.5mm screw no problem, but the curved slot is
too narrow, so tightening it up puts the whole thing significantly out
of line. *There weren't any screws supplied but it looks like it needs
a screw with a narrow shank for the first 5mm from the head. *It
should be simple, in principle, to stroke the threads from a spare
screw using a file but it needs to be held tight while filing and
clamping it in a vice will just wreck the working part of the thread.
If it was any other size, I would put a couple of nuts on it, but
electrical screws are 'special' and nobody sells that size nut (M3 and
M4, ok, but not M3.5).
So....How would you resourceful people do it? *I have thought of
drilling the slot it goes through to widen it, but I'm reluctant to
start carving up a 70-quid controller - screws are, at least, cheap
enough to wreck one or two! *Clearly, there's no point in spending
ages (well relatively, I know they're pretty soft) filing away to end
up with a screw that won't go into the box because I've cream-
crackered the thread.

Wrap some 0.5mm iron wire round the screw thread, many turns, so it
sits in the screw thead. then you can put it in the drill chuck and
the wire takes the force. Still need to go easy on it force wise, but
it should work.


NT

On Wed, 29 Oct 2008 10:05:52 -0700, GMM wrote:

I have this heating controller to wire up and screw onto a standard
electrical back box. Instead of a standard hole straight through for
each screw, it has a curved 'keyhole' shaped slot (presumably to allow
a bit of rotation to get it nice and straight).

Oh, those! groan

Take it back and get a different make ;-)

--
YAPH http://yaph.co.uk

I'm more non-competitive than you

The message
from "ARWadsworth" contains these words:


Buy a couple of screw longer than you need, clamp the end in a vice, file
down what you need to and then cut off the threads knackered by the vice to
leave you with the correct length screw.

At least one person has a sane answer.

One additional point -- since presumaby no die is readily available to
clean up the thread and since no M3.5 nuts are likely to be readily
available, take a metal backbox and remove one or more of the tapped
lugs -- if you've a four-lug box it will still be usable afterwards --
and run the removed lugs up the thread before cutting off the surplus
length below them. Then when you unthread them they'll clean up the
thread nicely for you.

On Wed, 5 Nov 2008 21:52:48 GMT, Appin wrote:

The message
from "ARWadsworth" contains these words:


Buy a couple of screw longer than you need, clamp the end in a vice, file
down what you need to and then cut off the threads knackered by the vice to
leave you with the correct length screw.

At least one person has a sane answer.

No, mine was the sane answer 6 days ago.

I'm truly amazed that everyone else came up with all sorts of weird and
wonderful ways to cut back the thread, when the logical thing to do is ask
the supplier or manufacturer if screws should be supplied with the fitting.
If not, then and only then is it time to prat about.



--
The Wanderer

All wighy, rho sriyched yhe ket pads on my ketboawd?

"Appin" wrote in message
...
The message
from "ARWadsworth" contains these words:


Buy a couple of screw longer than you need, clamp the end in a vice, file
down what you need to and then cut off the threads knackered by the vice
to
leave you with the correct length screw.

At least one person has a sane answer.

One additional point -- since presumaby no die is readily available to
clean up the thread and since no M3.5 nuts are likely to be readily
available, take a metal backbox and remove one or more of the tapped
lugs -- if you've a four-lug box it will still be usable afterwards --
and run the removed lugs up the thread before cutting off the surplus
length below them. Then when you unthread them they'll clean up the
thread nicely for you.

The cheap crimp tools have threaded holes for you to cut bolts, you screw
through one of these first and then you chop the end off, Unscrewing it
reforms the thread if needed. You could leave it dangling from the vice
while you file the end and then chop it off.

The message
from "dennis@home" contains these words:

The cheap crimp tools have threaded holes for you to cut bolts, you screw
through one of these first and then you chop the end off, Unscrewing it
reforms the thread if needed. You could leave it dangling from the vice
while you file the end and then chop it off.

The question is whether the said cheap crimp tools have a M3.5 threaded
hole. It is rather a specialised size.

"Appin" wrote in message
...
The message
from "dennis@home" contains these words:

The cheap crimp tools have threaded holes for you to cut bolts, you screw
through one of these first and then you chop the end off, Unscrewing it
reforms the thread if needed. You could leave it dangling from the vice
while you file the end and then chop it off.

The question is whether the said cheap crimp tools have a M3.5 threaded
hole. It is rather a specialised size.

They screw into the one I have quite well but the numbers have rubbed off so
I don't know what size it says.

The message
from "dennis@home" contains these words:



"Appin" wrote in message
...
The message
from "dennis@home" contains these words:

The cheap crimp tools have threaded holes for you to cut bolts, you screw
through one of these first and then you chop the end off, Unscrewing it
reforms the thread if needed. You could leave it dangling from the vice
while you file the end and then chop it off.

The question is whether the said cheap crimp tools have a M3.5 threaded
hole. It is rather a specialised size.

They screw into the one I have quite well but the numbers have rubbed
off so
I don't know what size it says.

Well, you have a nice simple answer to the problem, then :-)

On Thu, 6 Nov 2008 20:59:18 -0000, "dennis@home"
wrote:



"Appin" wrote in message
...
The message
from "dennis@home" contains these words:

The cheap crimp tools have threaded holes for you to cut bolts, you screw
through one of these first and then you chop the end off, Unscrewing it
reforms the thread if needed. You could leave it dangling from the vice
while you file the end and then chop it off.

The question is whether the said cheap crimp tools have a M3.5 threaded
hole. It is rather a specialised size.

They screw into the one I have quite well but the numbers have rubbed off so
I don't know what size it says.

It will be 3.5mm or 4ba depending on the age. I have one somewhere
from 1980s. Difference in thread is so minor they are interchangeable.