Surface Moulded Boxes

[Distorted Vision]

I'm in the process of replacing some of the switches and surface moulded boxes in our house for cosmetic reasons. Some of the switches are really dirty, scratched etc and some the moulded surface boxes are cracked etc.

Anyway I have a question and I know its going to sound really stupid to alot of you. But what is the best of breaking the knockouts on the moulded boxes to ensure clean straight edges. The first one I tried I used a pair of plier but it was a bit of a mess - good job they are so cheap. Am I missing something here. Is there a recommended way.

Many thanks!

[Tim S]

Distorted Vision coughed up some electrons that declared:

Not stupid at all...

My amateur trick is to slice with sides with a junior hacksaw, snap out with pliers, punch the inner skin with a screwdriver (if applicable) and finish with a few strokes of a 1/4" full size coarse square file through the lot. Dead neat and nice square smooth edges - not the fastest way though. If doing a lot, I pre-prep them in one go on the bench with a big cup of coffee.

Wonder what the pro's do?

Cheers

Tim

[meow2222]

Sounds like you could save yourself a lot of work here. Take all the accessories off, temporarily making the wires safe, and run em all through the dishwasher. Give them all a full week in a warm dry room to dry out, and they'll all be ready to refit, as clean as new. You might want to insulation check them for peace of mind - the success record is extremely good.

NT

[Dave Plowman (News)]

Use decent metal clad units for surface mount. Much stronger. And in the scheme of things not really much more expensive.

[John]

As the plastic is not porous why should they need such extensive drying?

[ARWadsworth]

Usually the knockouts do not need to look perfect as they are covered by trunking. I use my wirecutters to break the knockouts. If the knockout needs to look good then it is hacksaw time.

Adam

[Rod]

Have also used a Dremel cutting disc for this. Maybe someone with experience can manage by applying judicious wallops. Not me!

[Bob Eager]

Dremel.

[John]

[Bob Eager]

Mine usually end up with trunking on them if they are surface knockouts. Even just the trunking 'terminator' is a bit like a grommet and could be used...

[meow2222]

They also contain semi-closed cavities, making evaporation slow, and you really dont want to fit anything with moisture still in it. A week is overkill, but its meant to be.

NT

[Distorted Vision]

Putting the fittings in the dishwasher isn't really an option since they are in use every day so a week is impossible. Besides some of them are scratched or cracked. White moulded switches and sockets are so cheap so I want to replace them.

I realised just after posting that a hacksaw or a Dremel is whats needed. I haven't used my Dremel for ages so I'll have to check I've got some cutting discs. Tim I was trying to get hold a square file. I assume a full size file means its 8" long? I also can't find a coarse one most of the ones I've found are second cut. Does it make much difference? I found this:

this be suitable?

Cheers!

[Dave Plowman (News)]

Complete waste of time for a job this small - a junior hacksaw will do just fine.

A set of needle files is ideal for this sort of thing.

[Tim S]

Dave Plowman (News) wibbled:

Yes - that hacksaw takes just a few strokes so it's not really an effort.

Needles work too. I happened to have a big (prob 8" long) to hand and being just a little less wide than the hole also required only a few strokes to clean up - and it squares everything off without really trying.

Cheers

Tim

[ARWadsworth]

If your dishwasher fixes cracked plastic surface mount boxes please give me the name and model no of your dishwasher. I could do with some easy money.

Adam

[Distorted Vision]

Mine still don't come out too neat. The problem is when I use the pliers after cutting with a hacksaw it makes a mess of it instead of leaving a clean straight edge. Maybe a tile scribe and nipper might do the trick?

[Tim S]

Distorted Vision coughed up some electrons that declared:

Unless you're really unlucky, the pliers should break it off "short", then you can clean up with a file. I've only found that it over-breaks (chips the box well beyond the hole area) if you don't use a hacksaw first to slice the side.

As I mentioned previously, I've found a big (8" ish) square file to be particulalry quick and effective.

Cheers

Tim

[Distorted Vision]

Hi Tim,

Yes thats exactly whats happening it chips it beyond the hole. I might try with different pliers but thats why I was thinking of using a tile nipper instead.

Cheers!

[Tim S]

Distorted Vision coughed up some electrons that declared:

Try deliberately breaking it short - don't present the end of the pliers right upto the back edge of the snap line.

[Dave Plowman (News)]

Given you'll be seeing the cable if you can see the knockout, does it really matter? Most would use trunking to avoid seeing the cable and this would also cover up the knockout.