Best way to drill out metal

Discussion in 'Engineers' Talk' started by Jay459, Sep 2, 2017.

  1. Jay459

    Jay459 Member

    i have been building a trailer and it's been quite frustrating drilling out the screw holes for my m6 stainless countersunk bolts.

    But I've got a lot of it done. I'm also fixing trailer hooks that came with screws. I tried drilling pilot holes as at first I tried to put the screw straight in with my impact driver but no joy. I got one trailer hook done then on the next my small drill bit broke

    Will this new bit set and lube oil help me do things a bit quicker

    https://www.amazon.co.uk/gp/aw/d/B0...rjXSL&ref=plSrch#immersive-view_1504326818154
     
  2. KIAB

    KIAB Super Member

    Use quailty HHS bits, lube & a slower speed, shouldn't need a pilot hole for M6.

    If you got a Cromwell store nearby have a nosey.

    https://www.cromwell.co.uk/
     
  3. KIAB

    KIAB Super Member

    You need a speed of around 1000 rpm for mild steel for 6mm hole & lower for a 7mm hole, any higher & you burn out (overheat/soften them) the drill bits, then you won't drill anything with them.
    Centre puch the metal will stop bit sliding, & plenty of lube, no idea what drill your using, I'm lucky enough to have 'Rachel' a large elderly 12 speed bench drill for any metalwork drilling.
     
  4. Bob Rathbone

    Bob Rathbone Screwfix Select

    Drills normally get hot when they are blunt. As others have said, get good quality drills. As a general rule a smaller drill bit requires a higher speed, look on the web for recommended drill bit speeds for the material you are drilling.
     
  5. malkie129

    malkie129 Screwfix Select

    Everything that Kiab has said is correct. Chinese drill bits are a waste of time. Dormer are the best,but otherwise a good quality drill bit with Supacut or similar as the lube.
     
  6. KIAB

    KIAB Super Member

    Poke you nose into a Cromwell Tools store, great bits Dormer, you can get then in jobber & stub versions.
     

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