Advice Needed Best drill bit for metal

[Captain Jack]

Hi,

Could someone suggest me the best drill bit to buy for drilling into metal? I keep buying "titanium" Bosch ones from B&Q as a set but after a few drills, they become blunt and unusable.

I don't mind spending a bit more on something that will last - generally use size 8 and 10 but a good set will be fine too.

Alternatively, does something exist to sharpen existing bits - and actually works?

Thanks
CJ

 

[Archived-1]

When I used to work with steel, I used to sharpen my own check the link CJ, also when drilling use a very low speed and it helps to use a little oil, as for a good bit now days I have know idea, I work with wood mainly now.

 

[hairybadger]

When I used to work with steel, I used to sharpen my own check the link CJ, also when drilling use a very low speed and it helps to use a little oil, as for a good bit now days I have know idea, I work with wood mainly now.

There is a (notional) ideal speed for each metal and bit diameter. You can look up "drill speed calculator" or something like that.

 

[PaulR]

Rather than buy sets why not buy individual ones? I buy mine at Tool Station. They're cheaper than Screwfix but there are less of them around. You may have to go to Screwfix (who are, incidentally, owned by the same company that owns B&Q).

But why are they wearing out so much? What are you drilling?

 

[Captain Jack]

But why are they wearing out so much? What are you drilling?

Just through metal - steel between 2 and 5mm thick. Maybe I am doing it wrong - too fast and certainly no oil.

 

[hairybadger]

Just through metal - steel between 2 and 5mm thick. Maybe I am doing it wrong - too fast and certainly no oil.

hmmm didn't know about the oil will bear it in mind next time....

 

[Channel Hopper]

Oil is less efficient than water in carrying away the heat from the centre of the bit. In lathe work the lubricant is a water soluble oil to offer clean cutting, cooling and fast debris removal

 

[sonic1]

Always used oil and a slow drill, common sense says pressing hard in to metal with a fast drill will create heat and melt the end of the drill.
Easily sharpened as shown in post 2 and a decent bit will last ages is looked after.

 

[purplemarina]

I use dormer drills very good quality and seem to last forever, they can be quiet expensive but ive had some bargains off eb*y.

 

[Piltdownpaul]

Reducing the drill speed should help,are the drill bit ends "blueing" after drilling, if so there's too much heat about too.

 

[Terryl]

This all depends on the type of steel being drilled, how thick, how hard, how big of a hole.

For thick steel a slow speed mounted in a drill press with a water base lube should be used, a big hole should be drilled in several steps, the harder the steel the harder the drill bit needs to be, some steels need a different bit then others.

Look here for some good choices, http://www.mcmaster.com/#standard-drill-bits/=qmyw20

 

[Vipersan]

Wherever possible ..
I use a lower speed in a stand/press drill ..
& Individually purchased drill bits..rather than those cheap kits..
And a high speed twist drill if I have to work with a hand drill.
Always start with a smaller pilot and work up size in 2mm steps until desired size achieved.
No specific brand comes to mind but Dormer are good.
My latest addition is a step drill (obviously plate only to depth of about 6mm)..which is superb for copper/Alluminium ..even mild steel if it's not too thick..
rgds
VS