I've got a couple of wall lights for use in the bedroom. They're actually
meant to be permanently wired but I need to add flex to them so that I can
plug them into a standard 13A socket. There's a picture here
http://www.thelightingsuperstore.co....roductid=44427 and,
although these are not the actual fittings I've got, this illustrates the
problem very well.

The bottom of the fitting is curved and I need to drill a hole to take a
rubber grommet that will then allow an entry for some black 3-core 0.5mm
flex. I've never tried to drill on a curve before - any particular
techniques to it?

TIA

"Pete Zahut" wrote in message
...
I've got a couple of wall lights for use in the bedroom. They're actually
meant to be permanently wired but I need to add flex to them so that I can
plug them into a standard 13A socket. There's a picture here
http://www.thelightingsuperstore.co....roductid=44427 and,
although these are not the actual fittings I've got, this illustrates the
problem very well.

The bottom of the fitting is curved and I need to drill a hole to take a
rubber grommet that will then allow an entry for some black 3-core 0.5mm
flex. I've never tried to drill on a curve before - any particular
techniques to it?

TIA


Not really in my experience - Assuming the material is metal, like the one
you linked to, to avoid the drill bit wandering, you would be best off using
a centre punch to mark where you want the hole first.

--
Toby...
Remove pants to reply

On 18/10/2010 12:11, Pete Zahut wrote:
I've got a couple of wall lights for use in the bedroom. They're actually
meant to be permanently wired but I need to add flex to them so that I can
plug them into a standard 13A socket. There's a picture here
http://www.thelightingsuperstore.co....roductid=44427 and,
although these are not the actual fittings I've got, this illustrates the
problem very well.

The bottom of the fitting is curved and I need to drill a hole to take a
rubber grommet that will then allow an entry for some black 3-core 0.5mm
flex. I've never tried to drill on a curve before - any particular
techniques to it?

TIA



Make sure the fitting is well held, ideally with something solid behind
the thin metal. Make a decent centre punch dent and start with a small
drill that is good and sharp. Then use larger drills. Better still use a
tapered reamer to open up the starter hole.
http://www.toolstation.com/shop/Hand...0/sd150/p11421
This won't leave ragged edges.

Can you drill from the inside? If you wander at first it won't show.

Peter Scott

You would need to place the metal over something to use as an anvil, and
then centre punch where you want to start drilling. Failing that, a U
shaped notch would probably do as well - couple of snips with string
side cutters, wiggle the tab created until it fatigues and falls off,
then file to final shape.
lamp to sit on, and have the cable exit throug that.


I was going to suggest a slot, but in my experience wiggling to fatigue
the tab is likely to distort the metal that its attached to.

Peter Scott

Peter Scott wrote:
You would need to place the metal over something to use as an anvil,
and then centre punch where you want to start drilling. Failing
that, a U shaped notch would probably do as well - couple of snips
with string side cutters, wiggle the tab created until it fatigues
and falls off, then file to final shape.
lamp to sit on, and have the cable exit throug that.


I was going to suggest a slot, but in my experience wiggling to
fatigue the tab is likely to distort the metal that its attached to.

Peter Scott

Angle Grinder.
--
Adam

On 18/10/2010 12:40, ARWadsworth wrote:
Peter wrote:
You would need to place the metal over something to use as an anvil,
and then centre punch where you want to start drilling. Failing
that, a U shaped notch would probably do as well - couple of snips
with string side cutters, wiggle the tab created until it fatigues
and falls off, then file to final shape.
lamp to sit on, and have the cable exit throug that.


I was going to suggest a slot, but in my experience wiggling to
fatigue the tab is likely to distort the metal that its attached to.

Peter Scott

Angle Grinder.

Thermit???

John Rumm wrote:
On 18/10/2010 12:40, ARWadsworth wrote:
Peter wrote:
You would need to place the metal over something to use as an
anvil, and then centre punch where you want to start drilling.
Failing that, a U shaped notch would probably do as well - couple
of snips with string side cutters, wiggle the tab created until it
fatigues and falls off, then file to final shape.
lamp to sit on, and have the cable exit throug that.


I was going to suggest a slot, but in my experience wiggling to
fatigue the tab is likely to distort the metal that its attached to.

Peter Scott

Angle Grinder.

For once the canonical uk.d-i-y answer is actually pretty good ;-)
Clamp firmly, and take little nibbles to avoid overheating the metal.

Thanks for all the quick answers guys, that's brilliant :-)

On Mon, 18 Oct 2010 12:24:45 +0100, Toby wrote:

"Pete Zahut" wrote in message
...
I've got a couple of wall lights for use in the bedroom. They're actually
meant to be permanently wired but I need to add flex to them so that I can
plug them into a standard 13A socket. There's a picture here
http://www.thelightingsuperstore.co....roductid=44427 and,
although these are not the actual fittings I've got, this illustrates the
problem very well.

The bottom of the fitting is curved and I need to drill a hole to take a
rubber grommet that will then allow an entry for some black 3-core 0.5mm
flex. I've never tried to drill on a curve before - any particular
techniques to it?

TIA


Not really in my experience - Assuming the material is metal, like the one
you linked to, to avoid the drill bit wandering, you would be best off using
a centre punch to mark where you want the hole first.

After marking with a punch, I've always started on a curve with a
wheel-brace (if it's possible to secure the part being drilled) and 'rocked'
the wheel. The bit won't wander as it does only about ½ - 1 turn.
--
Peter.
The gods will stay away
whilst religions hold sway

On 18/10/2010 13:05, John Rumm wrote:
On 18/10/2010 12:40, ARWadsworth wrote:
Peter wrote:
You would need to place the metal over something to use as an anvil,
and then centre punch where you want to start drilling. Failing
that, a U shaped notch would probably do as well - couple of snips
with string side cutters, wiggle the tab created until it fatigues
and falls off, then file to final shape.
lamp to sit on, and have the cable exit throug that.


I was going to suggest a slot, but in my experience wiggling to
fatigue the tab is likely to distort the metal that its attached to.

Peter Scott

Angle Grinder.

For once the canonical uk.d-i-y answer is actually pretty good ;-) Clamp
firmly, and take little nibbles to avoid overheating the metal.

For once I agree, but mark where you want the hole to be and very gently
use the angle grinder to make a small light cross on the curve. This
will act as a scribed mark for the drill to bite. Start off with the
smallest twist drill you have, to avoid wandering of the tip.

Good luck.

Dave

"Pete Zahut" wrote in message
...
I've got a couple of wall lights for use in the bedroom. They're actually
meant to be permanently wired but I need to add flex to them so that I can
plug them into a standard 13A socket. There's a picture here
http://www.thelightingsuperstore.co....roductid=44427 and,
although these are not the actual fittings I've got, this illustrates the
problem very well.

The bottom of the fitting is curved and I need to drill a hole to take a
rubber grommet that will then allow an entry for some black 3-core 0.5mm
flex. I've never tried to drill on a curve before - any particular
techniques to it?


I did very similar once. I found it easier to drill from the inside out.
It meant the drill going into the hole at a slight angle but I placed a bit
of scrap metal between the drill tip and inner face to prevent it moving
forward and started with a small drill. Once the hole was started this
piece of scrap was removed. The curve had no effect because the drill
would have had to climb up. Any imperfections in the shape of the hole were
hidden by the grommet. Of course you might have to remove the switch
temporarily to make space to work.
--
Tinkerer