drills question

[johnakay]

which is better for drill mild steel and some times s/steel?.
hss ground
hss titanium
cabolt.

 

[langy]

Any of them, I favour Dormer A002 split points for S/S

 

[piman]

Hello Johnakay,

it's not what drill but how you drill, not too fast and plenty of pressure, if the drill stops drilling it will work harden and it's then very difficult to complete the hole.

Alec

 

[brightspark]

dont forget use cutting compound

 

[mart]

Also, a drill press (if you don`t already have one) makes a massive difference compared to a an electric hand drill.
Bits-I prefer multi-construction drill bits (available at T Station).

 

[Paul G]

which is better for drill mild steel and some times s/steel?.
hss ground
hss titanium
cabolt.

Cobalt is better than all of those.

 

[Ed.]

x2 for cobalt drills

 

[langy]

Cobalt is better than all of those.

Indeed but not actually needed.

 

[Kent]

Std HSS will do just fine for most jobs, don't waste money on stuff you don't need pay more for. Learning to sharpen properly is way more important than buying expensive drills that keep their edge better. Leave the fancy stuff to drilling fancy metals imo.

Was on a job with a mate (a spark) and he kept chucking drills as they blunted, seriously he thought they couldn't easily be sharpened! I sharpened them and gave them back, he now has a serious surplus of just one size

One thing worth bearing in mind there are some very poor drill bits being sold at present with reverse rakes ground in from new and even bent from the box so go for good respected brands

 

[gordon stephenson]

This question crops up now and again, Good advice above, big thing is do not let the drill just rub without cutting, Good steady pressure and keep watching to make sure the drill is actually drilling,

 

[johnakay]

the only drills that find difficult to sharpen correctly are those that are less than 3 mm.
the reason why I ask above was the cobalt drill I've never used them or seen them well not to my knowledge anyway.
not trying to be a clever b*gger I do know how use drills etc.
what I should have ask is what the difference is cobalt compared to others ,I was in a rush so I just typed in with out any though coming off the PC.
thanks for the replies.

 

[Hitch]

Std HSS will do just fine for most jobs, don't waste money on stuff you don't need pay more for. Learning to sharpen properly is way more important than buying expensive drills that keep their edge better. Leave the fancy stuff to drilling fancy metals imo.

Was on a job with a mate (a spark) and he kept chucking drills as they blunted, seriously he thought they couldn't easily be sharpened! I sharpened them and gave them back, he now has a serious surplus of just one size

One thing worth bearing in mind there are some very poor drill bits being sold at present with reverse rakes ground in from new and even bent from the box so go for good respected brands

Spot on.

People are so tempted to pull the trigger a bit further in if its not cutting...just makes matters worse.
Some of the cheap ones available are absolute rubbish. We had a case floating around at work, i got through most of the 5mm bits drilling aluminium
Had some that the flutes untwisted on, some that bent 45 degrees...probably just about okay for drilling softwood, thats about it.

Cobalt bits, not a massive fan to be honest, they hold an edge well, but trying to drill out half holes that dont line up, with the drill jammed in a corner, they just seem to snap off.
Same with the A002s, nice bits to use, but only if used properly.

 

[Rig Pig]

Cobalt bits are good for hard material but as Hitch says they are brittle, a decent set of Presto or Dormer HSS bits will do most workshop jobs, if you're doing sheet work reduce the angle when you regrind to stop it snatching.

 

[Kent]

the only drills that find difficult to sharpen correctly are those that are less than 3 mm.
the reason why I ask above was the cobalt drill I've never used them or seen them well not to my knowledge anyway.
not trying to be a clever b*gger I do know how use drills etc.
what I should have ask is what the difference is cobalt compared to others ,I was in a rush so I just typed in with out any though coming off the PC.
thanks for the replies.

I got a lot of fancy drill bits given me from a good mate who worked for a big Aerospace company (say no more about that one) found no improvement on normal drilling normal steel. Less than 3mm will normally break before they need a sharpen as they are basically like a rich tea biscuit dunked in a steaming hot brew, slightest excuse and they just give up

 

[brightspark]

nothing fancy just good make hss drills and cutting compound and a decent firm pressure and u can drill loads of holes in stainless before they go blunt

 

[hotrodder]

what I should have ask is what the difference is cobalt compared to others ,I was in a rush so I just typed in with out any though coming off the PC.
thanks for the replies.

Cobalt is one of many, many flavours of HSS and there are various flavours of HSS-Co aka HSS-E... M35 (5% Co) and M42 (8% Co) are the two common ones. Cobalt raises the hot hardness and improves abrasion resistance but the trade off is that they're generally more brittle as said

FWIW i countersunk 440 holes laser cut holes in 304L last week (yes it was very boring) using an 8.3mm Alpen-Maykestag 'regular' HSS uncoated countersink. I actually used two but both still have plenty of life left in them before they'd need sharpening binning. They were 1/5 the price (and 1/3 the list price) of Dormer g136 HSS and cheaper than many mystery brands or tat with silverline/faithfull written on the box. Dunno how competively priced their drills are

 

[Paul G]

I often drill holes for 3.2 stainless pop rivets with a 3.3 cobalt drill in a small electric hand drill.
Been making this particular stainless item on and off for quite a few years now and have settled
on cobalt after using other sorts of drill bits.
I wouldn't go to the expense of cobalt for all drilling jobs but they definitely have their uses. (IMHO)

Paul G