Drilling a hole in mild steel - how hard should it be?

[skotl]

Following on from this post, and the two follow-ups, am I just doing something wrong in trying to drill holes in mild steel?

I've been using no-name generic HSS bits and trying to drill pilot holes into 1.5mm and 3mm steel and all I've achieved is making a neat little divot in each (using 2mm / 3mm bits).
I've tried going slow and going fast, with and without cutting compound, and no difference.

In desperation I have discovered that a quick pulse from the plasma makes a lovely 2mmish pilot that I can then drill out.

Is my technique wrong or am I never going to get anywhere with cheap generic drill bits? If the latter, what would you suggest?

Bit of an embarrassing / basic question that I can't drill a hole in a piece of metal...

 

[DanielW]

Stop buying cheap drill bits,money in the wind.

 

[Rocketman]

2/3mm into 1.3/3mm steel should fly in. I assume you are using a pistol drill, if so it will want to be pretty well max speed with that size drill.

It may be the drill bits are total poo and blunt straight away.

 

[Screwdriver]

Cheap bits.

Get some carbide bits and some (genuine) HSS.

 

[Wedg1e]

Drill spinning the wrong way?

Could be the tip geometry is carp... or maybe it's poor mild steel. Diffficult but not impossible to regrind the tips of drills that small, give it a shot, nothing to lose.

 

[skotl]

Good stuff so far - I don't mind being told that the bits are the problem.
I don't mind spending money on decent tools but I've always considered drill bits to be like sandpaper; buy cheap, use once (well, a few times) then throw away.

So what should I look for in a new set of bits? Screwdriver mentioned carbide tips...
Is manufacturer more important than component material or vice versa?

Oh - and are we concluding that HSS means high-speed for steel? At what point do you switch to lower speed?

 

[MattH]

Pressure.

Lots of pressure.

 

[Wallace]

Post a photo of the drill bit cutting edges if you can. Plasma dross isn't kind to cutting edges.

 

[Rocketman]

skotl

HSS = high speed steel. It's the steel it is made from.

You don't have to spend a fortune on drills but like wise don't buy cheap crap. Even black and decker piranha drill bits aren't the end of the world.

Some of the expensive drills bits made out of more exotic stuff don't take well to anything other than sturdy machines.

 

[Digger6135]

Buy some Dormer or Guhring drills you wont go far wrong, high speed steel or cobalt steel. keep the drilling pressure up (vital if you drill stainless steel), and use cutting fluid, Rocol works very well.

Digger6135

 

[DanielW]

Presto or dormer.

 

[DanielW]

http://www.ebay.co.uk/itm/PRESTO-DI...LLS-0951M19-/350993795873?hash=item51b8dc4b21

 

[skotl]

Post a photo of the drill bit cutting edges if you can. Plasma dross isn't kind to cutting edges.

I know my current bits are sh*t so that won't help.

I did get a bloody fright yesterday when I was expanding a plasma hole with a 4mm bit - I wasn't wearing safety specs (who does when drilling?) and the bit shattered (not broke, shattered as in around six bits) on the dross and a portion hit me on the cheek a couple of centimetres below my eye.
That was definitely several lessons;

...plasma dross isn't kind to cutting edges...

And I'll wear specs when enlarging irregular holes.

 

[skotl]

Pressure.
Lots of pressure.

With the cheap bits I've been using, pressure just snaps them. Looks like it's a combination of better bits and cutting compound.

...Some of the expensive drills bits made out of more exotic stuff don't take well to anything other than sturdy machines.

Yep - I have noticed the difference between even a basic mains drill and a battery drill.

...and use cutting fluid, Rocol works very well...

Been using Rocol so I think we're coming back to the bits.

http://www.ebay.co.uk/itm/PRESTO-DI...LLS-0951M19-/350993795873?hash=item51b8dc4b21

Aha - these are much more expensive than any drill bit I have ever bought in the past.
I think that's a positive - buying 50 HSS bits for a tenner clearly isn't (literally) going to cut it.


Thanks all. So to summarise;

1. Decent drill bits (I'm going to start with the Prestos)
2. Rocol fluid
3. Decent drill, at high speed

 

[DanielW]

I could have linked you to their £15 singular bits but i'm summizing you have short arms and deep pockets..

 

[skotl]

I could have linked you to their £15 singular bits but i'm summizing you have short arms and deep pockets..

Couldn't find a decent deal on singles on the prestos so have gone with dormers;

2 x each of 2mm, 3mm, 4mm, 5mm, 6mm, 7mm and 8mm delivered for £38. All from http://www.ebay.co.uk/itm/261820372442

 

[brokenbiker]

buy decent bits and cutting fluid, I got fed up of constantly sharpening bits after a few quick uses so spent a bit of money on some better bits, mostly carbide and some cobalt and they go through most things like a knife through butter.

 

[penfold]

Cheapo cheapese drill bits are a pain and can explode due to rubbish alloy control and/or poor hardening control; sport can be had by buying blunt brand name drills at boot sales for pennies and sharpening them.

 

[skotl]

Cheapo cheapese drill bits are a pain and can explode due to rubbish alloy control and/or poor hardening control; sport can be had by buying blunt brand name drills at boot sales for pennies and sharpening them.

I've now learned that life, and my eyesight, are too short for this kind of sport! I'll report back on how these dormers perform - I've got plenty spare stock left from the welding trolley that resisted all attempts at drilling.

 

[penfold]

I get it a lot at work as the drones in the office have no concept of anything other than price, so cheap = good and the drills I get sent to sea with may either shatter as though made of porcelain or bend like toffee. If nothing else it makes for workshop time being quite exciting. I don't bother trying to drill holes in steel with the portable drill unless the hole is the size of one of the few decent drills that lurk at the back of the edge tool drawer, life's too short and I don't get paid enough put up with a faceful of steel splinters.