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Recommend Me Quality Drill Bits
BigDawgV8 - 6/12/20 at 12:34 PM

Hi All,

I need to drill a couple of 1.5 mm holes through some hard alloy.

Can anyone recommend me a suitable make and type of drill bit for this please?

Hopefully, I won’t have to buy a whole set just for a couple of holes!

Thanks in advance for the help.

Theshed - 6/12/20 at 01:01 PM

You could try PCB drills - usually carbide so hard but very brittle.

https://www.ebay.co.uk/i/184304256331?chn=ps&var=691996373957&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&itemid=691996 373957_184304256331&targetid=1065995239437&device=c&mktype=pla&googleloc=9044965&campaignid=10204071591&mkgroupid=104953044434 &rlsatarget=aud-629407027825:pla-1065995239437&abcId=1145987&merchantid=114950642&gclid=EAIaIQobChMI9YWJr7O57QIVmLPtCh3TiwdGEAQYBSABEg IK3PD_BwE

Or buy cobalt bits


£14 for 10


https://www.ebay.co.uk/itm/INDUSTRTIAL-QUALITY-1-5mm-HSCO-COBALT-DRILL-X-10/324246739135?epid=646225784&hash=item4b7e9c98bf:g:pS8AAOSw22pfJGtF />
As a single for £2.30

https://www.ebay.co.uk/itm/Presto-HSCo-8-Cobalt-Jobber-Drills-Imperial-Sizes-1-16-1-2-x-1-64/153787180853?hash=item23ce6e2735:g:4e4AAOSw9KBeDhfN

ReMan - 6/12/20 at 04:57 PM

Invest in a set of cobalt drills, I just got some and wished I'd had them years ago
Either way halfords do 2 for @£2.50

perksy - 6/12/20 at 09:57 PM

Buy the best quality drills you can

Safety glasses have saved me on a few occasions from cheap ones

indykid - 6/12/20 at 10:09 PM

What alloy and how hard is 'hard'? How deep is the hole?

As above, carbide would be my go to assuming it's some sort of hardened alloy steel, but you'll be lucky to finish a hole with a hand drill. I'd want to be using a pillar drill as a minimum, fast as it'll go, but really a milling machine would be best.

Presto, Dormer and Osborn all make very good HSS/HSSCo drills IME. Even cheap carbide is typically reasonable, even the Chinese stuff from BangGood, but as said, PCB drills get knocked out like shelling peas so they're very reasonably priced.

I presume you'll be drilling perpendicular to a face with an uninterrupted cut? If not, I'd expect the life of any drill, regardless of quality, to be VERY short unless you're VERY careful.

coyoteboy - 7/12/20 at 12:27 AM

Skip carbide and cobalt and go right for TCT (tungsten carbide tipped) - they have the hardness at the tip to get through stainless like butter but have a hss shaft to prevent brittle failure.

coyoteboy - 7/12/20 at 12:34 AM

Duplicate

[Edited on 7/12/20 by coyoteboy]

indykid - 7/12/20 at 09:02 AM

quote:
Originally posted by coyoteboy
Skip carbide and cobalt and go right for TCT (tungsten carbide tipped) - they have the hardness at the tip to get through stainless like butter but have a hss shaft to prevent brittle failure.


Do you have a link for these 1.5mm TCT drills?

pigeondave - 7/12/20 at 10:26 AM

quote:
Originally posted by indykid
What alloy and how hard is 'hard'? How deep is the hole?

As above, carbide would be my go to assuming it's some sort of hardened alloy steel, but you'll be lucky to finish a hole with a hand drill. I'd want to be using a pillar drill as a minimum, fast as it'll go, but really a milling machine would be best.


Is this correct advice?

I thought it was all about the pressure with metal drilling? Yes definitely use a pillar drill so you can get good pressure on the bit.
But as fast as it'll go?
I'm not sure that's correct.

Ah a quick look on the web and the bigger you go on the bit size the slower the rpm. As this is tiny, let 'er rip.

[Edited on 7/12/20 by pigeondave]

[Edited on 7/12/20 by pigeondave]

nick205 - 7/12/20 at 10:30 AM

It's mentioned above, but I'll say it again - always wear safety glasses!

Metal fragments is a really bad thing.

indykid - 7/12/20 at 01:00 PM

quote:
Originally posted by pigeondave
quote:
Originally posted by indykid
What alloy and how hard is 'hard'? How deep is the hole?

As above, carbide would be my go to assuming it's some sort of hardened alloy steel, but you'll be lucky to finish a hole with a hand drill. I'd want to be using a pillar drill as a minimum, fast as it'll go, but really a milling machine would be best.


Is this correct advice?

I thought it was all about the pressure with metal drilling? Yes definitely use a pillar drill so you can get good pressure on the bit.
But as fast as it'll go?
I'm not sure that's correct.

Ah a quick look on the web and the bigger you go on the bit size the slower the rpm. As this is tiny, let 'er rip.

[Edited on 7/12/20 by pigeondave]

[Edited on 7/12/20 by pigeondave]


Even at the tips of a 1.5mm drill bit running at 3000rpm you'll only be achieving ~45sfm. I appreciate the OP's not looking for production speeds and feeds, but the easiest way to break a small drill, apart from bending it, is to run it too slow with too much feed.

nick205 - 8/12/20 at 02:55 PM

quote:
Originally posted by pigeondave
quote:
Originally posted by indykid
What alloy and how hard is 'hard'? How deep is the hole?

As above, carbide would be my go to assuming it's some sort of hardened alloy steel, but you'll be lucky to finish a hole with a hand drill. I'd want to be using a pillar drill as a minimum, fast as it'll go, but really a milling machine would be best.


Is this correct advice?

I thought it was all about the pressure with metal drilling? Yes definitely use a pillar drill so you can get good pressure on the bit.
But as fast as it'll go?
I'm not sure that's correct.

Ah a quick look on the web and the bigger you go on the bit size the slower the rpm. As this is tiny, let 'er rip.

[Edited on 7/12/20 by pigeondave]

[Edited on 7/12/20 by pigeondave]



Definitely correct on the speed.

I'd also second the advice on using a pillar drill over a hand drill whenever possible. Pillar drills avoid andy undue hand/arm wobble , which ultimately puts stress on the drill bit. Pillar drills also give a much more perpendicular hole as well (no matter how good you think you are with a hand drill).