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

[Wendelspanswick]

Heller or Guhring both make decent drills with the added benefit that Toolstation stock Heller.
Drills over 12mm I tend to buy used Dormer or similar and resharpen, unless you really balls it up they will last you a lifetime.

 

[pedrobedro]

A friend of mine was drilling some 4mm wall box through both sides with a 12mm TiN coated bit on his pillar drill and was making heavy weather of it. The bit looked fine but it was not doing the job and he asked me to sharpen it. I didn't want to as it would remove the coating but he was adamant so I touched it up freehand on the bench grinder and handed it back. I was guessing the angle and didn't have my glasses with me so anything could have happened but he put it back in the drill and pressed on it flew through firing spirals up off the flutes. He used it for about another 20 holes to finish the job and put it back in the box. I've told him to invest in some decent drills but he's like, how often do I need them ?

 

[ukracer]

A friend of mine was drilling some 4mm wall box through both sides with a 12mm TiN coated bit on his pillar drill and was making heavy weather of it. The bit looked fine but it was not doing the job and he asked me to sharpen it. I didn't want to as it would remove the coating but he was adamant so I touched it up freehand on the bench grinder and handed it back. I was guessing the angle and didn't have my glasses with me so anything could have happened but he put it back in the drill and pressed on it flew through firing spirals up off the flutes. He used it for about another 20 holes to finish the job and put it back in the box. I've told him to invest in some decent drills but he's like, how often do I need them ?

Sounds like he does not need new drills just you round his place occasionally. Lol

 

[ukracer]

http://www.toolstation.com/m/part.html?p=40442

This seems like good value to test.....

 

[roofman]

Cancel the Ford Mustang Scott and buy decent drills

 

[brightspark]

decent quality hss drills pilot holes fairly fast speed a bit of cutting paste makes them cut faster and prolongs life.then the larger drill at slow speed and just sufficient pressure to get a good cut without it biting in

 

[tflnemesis]

Another vote for cobalt bits.... i use them all the time and they fly through everything, including stainless (why i bought em). Have to be extra careful using em in a pistol drill as they don't flex very much and have a tendency to snap.

Also the bigger ones 8mm+ have a tendency to chip the cutting edges when they go through thin stuff, especially if they snag, but as they aren't coated they can be resharpened easily enough.

 

[sparkysy]

I just got a tiny 3"bench grinder for re sharpening drill bits! I usually go for good quality bits but most Recently I have a new apprentice and I don't know how he manages it but he can blunt one in the blink of an eye, despite being shown several times how to drill a hole!

 

[roofman]

Another vote for cobalt bits.... i use them all the time and they fly through everything, including stainless (why i bought em). Have to be extra careful using em in a pistol drill as they don't flex very much and have a tendency to snap.

Also the bigger ones 8mm+ have a tendency to chip the cutting edges when they go through thin stuff, especially if they snag, but as they aren't coated they can be resharpened easily enough.

i cant seem to live with them myself as they chip to easy...get your self decent HSS drills...learn how to sharpen them on a bench grinder and theres no reason why you cant have them for years with them ending up half there length and still drilling holes

 

[T0rnado69]

i cheat for sharping my bits, as i use a Electric Drill Bit Sharpener
does from 3mm to 10mm. for any others i use the bench grinder.

surely when drilling thin stuff, it would be easier to put it on top of a piece of wood etc
as a backing, should stop the thin sheet from bending down when your apply pressure on the drill.

 

[skotl]

...surely when drilling thin stuff, it would be easier to put it on top of a piece of wood etc
as a backing, should stop the thin sheet from bending down when your apply pressure on the drill.

That's a good point- I always use wood backing with the pillar drill; in hindsight, I'm sure your suggestion would have helped.

 

[tflnemesis]

surely when drilling thin stuff, it would be easier to put it on top of a piece of wood etc
as a backing, should stop the thin sheet from bending down when your apply pressure on the drill.

That would be really nice, but most of the stuff i drill is stainless/ aluminium door frames and doors. I fit access control in factories and offices and 99% of the time the doors are in situ, so pistol drill all the way...

 

[mechman]

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...

I was on the rigs years ago and spotted a guy struggling to drill holes for pop rivets in sheet metal, I had to inform him that his drill was in reverse

 

[Ed.]

Only time I had trouble with drilling into a bit of plate was when I made a light pole base, turned out that the plate I thought was mild steel, was actually wear plate, I started using a standard HSS drill bit, then when that failed I switched to a new cobolt drill which dulled after 1 hole, ended up getting them cut with an Oxy/acet. Stainless can also be a pain, if you don't apply enough pressure, slower speed and lubricant, it will just sit there work hardening till the drill bit end melts into a red blob.

 

[T0rnado69]

That would be really nice, but most of the stuff i drill is stainless/ aluminium door frames and doors. I fit access control in factories and offices and 99% of the time the doors are in situ, so pistol drill all the way...

well that idea sure aint no good for your application.

I had to inform him that his drill was in reverse

LOL, bet he didn't know where to put his face.

 

[Turbo]

If you are going by the ebay route try to buy from a seller that one of the members here has used before, fakes have always existed on that site but this year has seen a massive increase and brand name tooling is the latest category to suffer.

In another post I asked board members to recommend a seller of decent quality genuine drill bits but got no replies!

Now don't laugh but if you want to try out cobalt drill bits Silverline do quite a decent drill bit and they are proper cobalt, not just coated. The guy in a local engineering supplies place recommended them & tbh I was skeptical but they are actually quite a decent bit.

 

[penfold]

Only time I had trouble with drilling into a bit of plate was when I made a light pole base, turned out that the plate I thought was mild steel, was actually wear plate, I started using a standard HSS drill bit, then when that failed I switched to a new cobolt drill which dulled after 1 hole, ended up getting them cut with an Oxy/acet. Stainless can also be a pain, if you don't apply enough pressure, slower speed and lubricant, it will just sit there work hardening till the drill bit end melts into a red blob.

You can get away with all sorts when drilling mild, but when it's stainless or tool steel or something more exotic, you need the right speed+feed, cutting lubricant and a sharp drill or you just end up generating heat.

 

[pedrobedro]

You can get away with all sorts when drilling mild, but when it's stainless or tool steel or something more exotic, you need the right speed+feed, cutting lubricant and a sharp drill or you just end up generating heat.

They were trying to enlarge a hole in a stainless exhaust bracket round at the bike shop and it was defeating everything they had. I read somewhere that you could use a masonry bit at high speed as long as you didn't want to use it again and it actually worked. You have to sacrifice the drill bit though.

 

[mantakev]

I used to use cheap hss drill bits and had them unwind to look like a reamer too.
Then bought a full set of new Presto and the difference was a amazing, only ever bought Presto or Dormer since.
( apart from the set in lidl I got for a laugh and did a good job on cast steel hubs, shhhhhhhhhhhhhh)

 

[julianthegypsy]

I was on the rigs years ago and spotted a guy struggling to drill holes for pop rivets in sheet metal, I had to inform him that his drill was in reverse

I've had to point out to someone that their drill was going backwards before too...after a lenghty discussion of all the reasons it wasn't working of course!