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Best way to make a 20mm hole in case with good finish?

Discussion in 'Case Central' started by AlphaMale1, May 3, 2018.

  1. AlphaMale1


    Joined: Apr 27, 2018

    Posts: 108

    Hey all,

    I require 2 20mm holes for some watercooling fittings through the roof of my case. What is the best way to achieve this with a clean hole?

    Is it centre tap + hole saw?

  2. clone


    Joined: Jul 11, 2003

    Posts: 5,678

    Location: Telford//west mids

    have a look for a step drill bit think that should work.
  3. Finners

    Wise Guy

    Joined: Mar 27, 2009

    Posts: 2,162

    Think with a hole saw or a step drill bit you are going to need a sacrificial bit of material underneath to help support the flimsy case material. I have no experience using either on sheet metal though.

    What case is it? Think higher quality would be better in this situation compared to a £20 thin gauge steel case. Aluminium would be even better.

    I have used one of these sheet metal hole punches once and it gave reasonable results but did warp a cheap steel case slightly but i was putting edging round the hole afterwards so it looked ok.


    Just for the record that was just the first one that popped up on google. I've never used that brand or shop before but its just an example
  4. HoneyBadger

    Wise Guy

    Joined: Aug 2, 2016

    Posts: 2,074

    Location: Hoo, Kent

    Masking tape it up, hole saw and maybe a small rubber grommet to save you painting it.
  5. stephenmarr


    Joined: Nov 25, 2009

    Posts: 145

    Step Drill

    Nothing else will be as good

    Water jet LOL
  6. Mel_P

    Wise Guy

    Joined: Feb 27, 2004

    Posts: 1,856

    Location: Kent

  7. Habakkuk

    Wise Guy

    Joined: Feb 7, 2017

    Posts: 1,004

    Are you going to be removing all your components first, or will they have to deal with the vibration/being showered in metal shards?
  8. LePhuronn

    Wise Guy

    Joined: Sep 26, 2010

    Posts: 2,013

    Location: Stoke-on-Trent

    Step drill bit is better than a 20mm hole saw in my experience. Or you could go all-in with a 20mm blacksmith's bit.

    You'll need to tightly clamp something underneath where you're drilling to support the panel you're drilling and to stop the hole from burring up and getting messy underneath. Then masking tape your top surface, center punch and do a pilot hole 1.5mm to 2mm. That should give you a nice start point to keep the bigger drill bit on point.

    I doubt you'd need any lube just to punch through a case; steel cases are only 0.6mm thick and aluminium cases cut like butter.