Hss,cnc,sds,titanium-coated,carbide?

[peter_m7uk]

Guys,

 

I've got a lot of metal drilling coming up and I want drill bits that won't go blunt after a couple of holes. There seems to be a lot of choice and a lot of acronyms like HSS-CNC, HSS-R and so on. What are they on about and what are the best drills that don't cost the Earth, like diamond or something?!

 

Ta,

 

Pete

[Guest TerryBarry]

On my all stainless 2B, I've used HSS Jobbers Drills from Screwfix

They are cheap and last reasonably well

I do have a set of Colbalt drills which I bring out when the metal seems to have been hardened close to welds and the odd bit of tube which seems from a different lot to the rest of the chassis.

When drilling stainless I've found that you need to keep the rotational speed down and apply firm steady pressure and a wee bit of lubrication.

With up to 3.5mm drill bits you tend to lose a few by snapping when drilling at awkward angles but at £2.09 for 10 (4mm) who cares

If you are drilling aluminium you might need a slightly better drill bit with good flute to carry away the swarf - I think these would be about £4 for 10 (4mm) - Irwin again from Screwfix ( and No I'm not on commission)

[Guest Battery Bill]

Pete

You should not have too many problems as you have "Aluminium (Or Steel)" to drill through. Stainless seems to be the difficult one for some people

Good Quality HSS ones should do fine Cobalt ones are the biz for Stainless.

[Guest Vic & Wendy]

Hi Pete, in my opinion the only way to go is colbalt and a good quality cutting fluid or paste. When drilling stainless keep the speed as slow as possible, if you are using a hand drill then just pulse it. Drill set plus cutting fluid £30.

 

Vic

[Guest elwe]

I started my all stainless 2B off usin cobalt drills but while they are hard they are too brittle and break a bit too easily. Now I use the cheap screwfix HSS jobber drills. Sometimes I even bother to resharpen them.

 

I found the 3.5mm drills too small for drilling pilot holes in stainless so now I use 4mm ones. Haivng said that I have recently started using an expensive 2.5mm bullet nosed drill for pilot holes. It goes through like a hot knif through butter and I haven't snapped it yet!

 

I did encounter a piece of 316 stainless angle (3mm thick) that required the use of cobalt drills. I did try using the screwfix HSS jobber ones but it was completely destroying one drill per hole.

[Guest Phil Slater]

In my experience when drilling stainless it is the Screwfix jobbers that are brittle and prone to breaking. With the smaller sizes twiglets seem more robust

[Guest Jaffer]

Hi Pete,

 

You are almost in danger of getting too much information !

 

There are loads of different types and styles of drills because there are loads of different conditions, materials and machines used to drill holes! Drilling is also as much to do with the speed and feed rate of the drill as the type of bit and material to be drilled. This is why 'we' can encounter problems, as most of the holes kit car builders drill, are done with various types of hand held power drills, which tend to be more difficult to hold square, set to the correct speed and apply the correct pressure/feed.

 

Cobalt drills [HSSCo] do tend to drill stainless more reliably than HSS, but like elwe says they can appear a bit brittle.... going for a Cobalt stub drill will help, there is less of it to flex!

 

There are quick helix drills that work very well in softer materials like Ally, Copper etc, [Although I am assuming that the material that you are looking to drill will not be that thick, so this is less important]. A light oil, parafin or WD40 is also a good idea for Ally as it helps prevent the ally sticking to the drill tip.

 

A good drill form is the A001 or A002 drills. These are a version of the regular 'jobber' drill that are much better at self centering and, as a rule, don't need pilot drilling. They are a good 'all round' drill for most regular materials. [Care needed when using these type to open up pre-drilled holes, they can tend to grab a bit ]

 

The other important thing to remember is that you are much more likely to break the last drill in any size, than one you have a spare for!!

 

Hope this helps!

 

Jaff

[Guest john]

I found the ones from work to be the best

 

I used 3.2mm cobalt . but i agree they are brittle, use them correctly. !

[Guest Phil Slater]

For info I reckon Warehouse Direct supply a good range of cobalt drills at a good price.

[harvs]

I just use Heller 19 pce Budget HSS Drill Bit Set - under £10 from machine mart. They've always seamed to work fine - just work up the drill sizes rather than going for pilot then big hole!

James

[peter_m7uk]

Thanks for all the info, guys

 

I think I'll just start with some cheap HSS ones, as mentioned, then maybe look to cobalt if I have any bother.

 

No one seems to have mentioned titanium coated bits. Any experience with them?

 

Pete

[Longboarder]

I wouldn't buy a set, just a dozen 3 or 4mm hss and a stepped drill like the ones below. They open up to whatever size you like and the originals I bought 5 years ago for my build are still going strong. Apart from broke the tip off one and the shank of the other. Still use em all the time.

 

Nigel

[Les Welsher]

No one seems to have mentioned titanium coated bits. Any experience with them?

I bought a set of titanium drills (1.5 - 8mm) just before I started building my car.

The two 3.2mm drills in the set lasted for quite a while (eventually snapped), I sharpened one so it was very short which was good for making pilot holes as you could apply lots of pressure without it breaking. I bought a further two more

3.2 mm titanium drills to finish off the kit. All the other size drills are still ok.

 

Les