# Drill Bit Advice



## Mikegtr (19 Feb 2022)

Drill bit advice on drilling metal. I occasionally will drill a hole in metal--anything--say from 1/8" plate to perhaps 1/2" solid bar. Sometimes brass to solid steel. There is as you know various metal bits to choose from. What coating drill bit would you use? Your knowledge welcome.


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## bourbon (19 Feb 2022)

If its only occasionally, HSS with plenty of cutting oil and a slow speed.


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## MARK.B. (19 Feb 2022)

+1 to the above and if you knacker the drill bit after a couple of holes they are cheap enough to replace


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## AES (19 Feb 2022)

+1 to both the above.


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## Inspector (19 Feb 2022)

I'll use whatever I have available but prefer Cobalt split point drill bits.

Pete


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## pgrbff (20 Feb 2022)

Bosch do a couple of types of HSS which can be found reasonably priced on Amazon. I think the brand/quality is important if you want them to last and work well.


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## clogs (20 Feb 2022)

If u buy the slightly dearer cobalt /Hss drills they last so much longer, can be resharpened....
and they dont need coolant for short uses.....
I'm gradually replacing all my norm HSS for the above.....
that's unless it says made in UK, USA, or Germany on the shank....


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## Gordon Tarling (20 Feb 2022)

Probaly best not to use 'normal' HSS drill bits on brass and plastics, as they will often catch, dig in and cause a problem. Here's one link to show you how to modify drills for use on those materials. People who have to do a lot of drilling on those materials often have a separate set of drills which have been modified specifically for that purpose.

G.


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## John Hall (20 Feb 2022)

Basically you get what you pay for…a lot of the cheap coated bits are just a gimmick..it wears off fairly quickly leaving chinesium underneath…then they’re useless….Four facet split point bits cope with most things depending on the quality


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## hlvd (20 Feb 2022)

You want HSS-G (ground from solid bar) or Cobalt.

Anything with HSS-R in the description is rolled and prone to breaking in the pilot hole sizes.


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## Bingy man (20 Feb 2022)

I had a problem recently drilling a hole in a knife blade. I was replacing the handle and needed to drill the steel to fit new rivets but nothing I had would touch it . Had to use plan b to complete the job . A week later I saw a set of drills for sale on a tv channel. The host was drilling break discs and concrete and tiles etc all at the same time with no cutting oil or coolant at all. Not wanting to be suckered by tv gimmicks I reluctantly ordered a set and tried them out as per the tv advert and for the price paid + a ten year guarantee I’m actually impressed. They seam to drill anything. Unfortunately the knife was completed before the drills arrived so I wasn’t able to put them to that particular task .


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## Dalboy (20 Feb 2022)

Gordon Tarling said:


> Probaly best not to use 'normal' HSS drill bits on brass and plastics, as they will often catch, dig in and cause a problem. Here's one link to show you how to modify drills for use on those materials. People who have to do a lot of drilling on those materials often have a separate set of drills which have been modified specifically for that purpose.
> 
> G.



+ 1 for modifying the cutting angle on a drill bit for certain materials and thicknesses. I am lucky in that I have at least two sets of drill bits in either metric or imperial one set of each modified for these occasions


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## AES (20 Feb 2022)

+1 for a couple of the posts above - if you're doing a lot of holes into plastics, and definitely into brass, it's well worth re-grinding the webs, or having 2 sets of every dia you need.

BUT the OP said, and I quote: ..... " I occasionally will drill a hole in metal--anything--say from 1/8" plate to perhaps 1/2" solid bar. Sometimes brass to solid steel. ". To me, the key words in the above quote are "occasionally" and "Sometimes".

Therefore, IME, just about any old HSS drill, coated or uncoated, will do that job/s. Including rolled HSS. Certainly good quality drills will last longer before needing re-sharpening than cheapos USUALLY will. But again, IME, there are quite a few unbranded cheapos about that are every bit as good as (or almost as good as) the name brands. As has been discussed here in a similar thread quite recently, the "trick" is to find out which cheapos are good, and there it seems that only buying and trying will answer that one.

But again, NOT a big deal for someone drilling only "occasionally" IMO. (Aldi/Lidl for example). 

So to repeat, I'd never recommend that someone who says he'll only do such jobs seldom/occasionally invests in good quality drill set/s, nor re-grind for the odd brass/plastic drilling job. Used sensibly, just about any old "jobbers" drill with no name brand WILL do those jobs perfectly adequately.


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## Mikegtr (20 Feb 2022)

Many thanks everybody for your knowledge--much appreciated.


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## Johnwa (21 Feb 2022)

If you dont want to pay Dormers prices (probably the best in Britain) try Heller. I've used them for drilling wood and metal and plastic. Its all down to how you use them, if you try to force them through, you'll get trouble. If you let the tool do the work you'll be fine with average jobber drill bits.


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