How to make holes in plastic boxes?

[OM2]

I need to make holes in plastic boxes.
The holes need to be clean and smooth ones.
I've drilled and it comes out looking like a big mess!
I need to be able to do many many times so need to figure out how to do in a quick and clean operation that only takes seconds.

See below for what I've done so far:

Thanks.

 

[JohnD]

What sort of drill did you use? It must be cold.

 

[Harry Bloomfield]

Take a piece of steel pipe, of the correct diameter, heat it up on a gas flame, then offer it to the plastic, where you need the hole.

 

[Stivino]

Why not put rubber grommets on the holes?

 

[Old Salt]

Piece of timber clamped inside the face of the box to drill into.

 

[Nozzle]

Use a stepped drill

http://www.tooled-up.com/artwork/prodzoom/B-S20506.jpg

 

[SFK]

Use a step or Cone drill.
Pre-drill a small 3mm hole first to mark where to use the Cone drill.
I would make a wood template with 3mm holes in it to mark where to put the 3mm drill holes.
And put tape on Cone drill or step drill to mark where to stop.

https://www.screwfix.com/p/erbauer-cone-drill-bits-3-14-8-20-16-30mm-3-piece-set/9031V?tc=MA2

 

[Harry Bloomfield]

Use a step or Cone drill.
Pre-drill a small 3mm hole first to mark where to use the Cone drill.

The plastic of those boxes, is quite brittle, trying to drill it, risks shattering it - which was why I suggested a hot piece of steel pipe.

 

[SimonH2]

Or use a Q-Max (or similar) cutter. Good, but expensive if you aren't using them a lot.

 

[big-all]

Piece of timber clamped inside the face of the box to drill into.

100% this

if you have loads make up 2 jigs
the face board needs to be deeper than the amount the drill point is protruding although once the wooden face discs have been cut out and removed from the face jig you dont need a auger/drill bit at all for holes sticking forward so can be cut short /retracted or removed dependent on design
this board can be cut to fit snugly between those ribs and the lip at the top
the inner one will be probably fitted to the width and base probably with shaped edges to locate accurately
you then with a solo clamp away from the drill area clamp them firmly together
the first 4 holes in situ will make the jigs complete as in the outer jig plate will now have a cut hole with a auger/drill hole on the inner plate
once set up you will only have to empty the hole saw off plastic discs every few boxes at the point the cutting teeth have less than 5mm behind them full off plastic

 

[Koolpc]

Plastic explosive

 

[robinbanks]

If you're using a dril like John pictured in #2, run it backwards, and make sure the plastic is warm

Prefer Mottie's suggestion. But looks like you could get away with smaller holes; try using a soldering iron?

 

[freddiemercurystwin]

Old Salt solution is the way to go.