Drill bits for metal

[sickasapike]

Looks like I need to buy an 8mm bit for drilling 2mm thick steel, I have nice new wood bits but nothing I'd like to use on metal.

I might as well buy a set, this one looks great, nice re-useable metal box.

https://www.screwfix.com/p/dewalt-hss-d ... eces/4191f

..but not available for click and collect, or delivery.

What brand would folk suggest ? - does any make shine above others for use on metal ?

I'm after a small set that has an 8mm bit, and one or maybe two bigger ideally, exclusively to use on metal, 30 quid tops perhaps.

 

[ColeyS1]

I'd say using cutting paste or fluid is as important as a decent drill bit.

Sent from my SM-G900F using Tapatalk

 

[Beau]

Dormer are pretty good IME. If you are going to Screwfix these are pretty good as well but not great for re sharpening. https://www.screwfix.com/p/dewalt-extre ... 3pcs/66597

 

[Bod]

For a one-off job, Dormer in the sizes needed.
Some of those less expensive sets are not well made, ok if you can resharpen......have seen a right hand drill sharpened left handed.

Bod

 

[sickasapike]

I'd say using cutting paste or fluid is as important as a decent drill bit.

Check, thanks.

 

[sickasapike]

Thanks for tips re bits, no Dormer on screwfix site unfortunately - not that they're the bees knees necessarily but I have a few items to get from there anyway, and as of recently they text an hour's delivery slot at start of the day !

I decided to just get the 8mm and a 9 and 10mm sizes I'll need right away, the natty dewalt set mentioned doesn't have an 8mm, or I'd have gone for it so will get the single dewalt bits and if I get the up-to-8mm set in future I'll have a matching set up to 10.

 

[MikeJhn]

The biggest mistake I made as a rookie was trying to drill a 8mm hole in the first place, instead of a 4mm, then a 6mm and lastly the 8mm and trying to drill too fast, I found that it did not matter if the bits where in the medium price rage they would work, I ended up buying a couple of those multi multi bit sets from 1mm too 10mm in a metal case, didn't pay much over £25.00 for them, but they have lasted well only had to replace those I have snapped in half in the small range, over enthusiasm and loss of feeling in the hands.

Mike

Phil found the set on a post lower down: https://www.amazon.co.uk/170-piece-Tita ... +drill+set

 

[sickasapike]

4mm, then a 6mm and lastly the 8mm

Thanks for the tip, happily I already have a 6mm hole and just need to expand it to 8mm.

I actually have an 8mm bit but it's one of those with the sharp point, and two blade edges rather than the normal ridged top type, so it'd be hard to centre and I think it'd make a bit of a mess - and I'm trying to keep those for wood anyway.

 

[MikeK]

Keep the speed at about 800 RPM for the 8mm drill and use some light motor oil as a lubricant. If you take your time, the drill will center in the 6mm hole and make a clean hole.

 

[MikeJhn]

4mm, then a 6mm and lastly the 8mm

Thanks for the tip, happily I already have a 6mm hole and just need to expand it to 8mm.

I actually have an 8mm bit but it's one of those with the sharp point, and two blade edges rather than the normal ridged top type, so it'd be hard to centre and I think it'd make a bit of a mess - and I'm trying to keep those for wood anyway.

From you description that's a brad point bit for timber, not a metal drilling bit, keep that for you timber work, if you are having trouble centring onto a metal piece of work, drill a piece of wood first and clamp it to the metal workpiece in the position you require than use as a guide for your bit.

For opening up a 6mm hole to 8mm a rat tail file turned in the hole will do it as well.

Mike

 

[Robbo3]

What a funny sized set!
Any HSS jobber drill set will do the job. What you don't say is what you are going to use ie battery or electric drill or a pillar drill.
A centre punch is helpful to stop the bit skating & drilling the hole in two or three steps tends to lead to a better finish.
Probably the most important is to secure small work so that it doesn't spin.

 

[MikeJhn]

What a funny sized set!
Any HSS jobber drill set will do the job. What you don't say is what you are going to use ie battery or electric drill or a pillar drill.
A centre punch is helpful to stop the bit skating & drilling the hole in two or three steps tends to lead to a better finish.
Probably the most important is to secure small work so that it doesn't spin.

Rather difficult to centre punch in the middle of a hole. :wink:

Mike

 

[Phil Pascoe]

Have a look at https://www.ukdrills.com/hss-drills

Or something like - https://www.amazon.co.uk/170-piece-Tita ... +drill+set

Get one with the DIN number. One like this is the best thing I ever bought - once in a while I sit with a micrometer and put all the loose ones back, and it's lasted me fifteen years - I've replaced some 3mms and 6mms, but that's it. It's surprising when doing repairs how useful the half sizes are.

 

[MikeJhn]

phil, up late or early?

That's the set I have from Amazon, just as a pointer each diameter has a specific length, so you can sort the diameter by the length of the bit, much easier than using a micrometer.

Mike

 

[DTR]

As the material is only 2mm thick, I suspect a step drill would be better. Jobber bits tend to bite or catch when going through thin sheet.

https://www.screwfix.com/p/erbauer-spir ... 20mm/8528d

The biggest mistake I made as a rookie was trying to drill a 8mm hole in the first place, instead of a 4mm, then a 6mm and lastly the 8mm and trying to drill too fast

It's not necessary to go up in that many steps. The chisel point of a jobber drill bit doesn't do any cutting so it needs to be relieved. The bigger the bit, the bigger the chisel point. The pilot hole only needs to be big enough to allow the chisel point of the following drill through. Your 4mm pilot will have been big enough for the 8mm to follow, without needing the 6.

I absolutely agree with you on the slow speed though. I rarely, if ever, take my pillar drill out of the slowest speed.

 

[marcros]

Have a look at https://www.ukdrills.com/hss-drills

Or something like - https://www.amazon.co.uk/170-piece-Tita ... +drill+set

Get one with the DIN number. One like this is the best thing I ever bought - once in a while I sit with a micrometer and put all the loose ones back, and it's lasted me fifteen years - I've replaced some 3mms and 6mms, but that's it. It's surprising when doing repairs how useful the half sizes are.

I use UK drills quite often for odd sizes required for drilling pen blanks. I have used the jobber drills on metal too, but i don't do that much metal drilling.

They tend to sell them in 5's in some sizes. If you only want a single, look at their ebay store.

 

[Lons]

Like Marcros I use UK drills and buy what I need and find them decent quality. Nice to have sets, I have several but most just sit in the box unused.

 

[Phil Pascoe]

phil, up late or early?

That's the set I have from Amazon, just as a pointer each diameter has a specific length, so you can sort the diameter by the length of the bit, much easier than using a micrometer.
Mike

Up early. At least it's only insomnia and no longer extreme pain and morphine addiction. :lol:
Yes, they're all different lengths, but as so many strays have crept in to the set that aren't I invariably measure them anyway. I think there are more in it now than when it was new.

 

[sickasapike]

Phew, lots of great advice, yep, I'll be using a drill press so the piece will be firmly held, I'll use 800 or closest speed I have thanks. I'm picking up some cutting oil today, bits arriving tomorrow.

The DeWalt ones have a flat edge on the blunt end, one ofd the reasons I chose them. I do find however hard I clamp a bit, with gloves and grunting, that it can still spin when drilling deep into hard wood - that's one for another thread though !

The only round file I have is slightly too big, only about 1cm goes in, I tried to get a rythm going but hard to keep the pressure on/the file in and I need it to line up exactly with the slot below so I gave up doing it that way, it didn't strike me to buy a smaller file but I can see myself doing a bit of metal drilling here and there so want to get a few bits to keep for just that.

Such a big thread to drill one little hole ! - I really appreciate all the advice guys; while I've a little bit of experience with wood, I've almost never worked with metals so appreciate the hand-holding

 

[Phil Pascoe]

Go to garden machinery or agricultural supplier and get some chainsaw files - they're probably the cheapest half decent files on the market as they're made and sold in huge numbers.