HSS-G drill bits
Discussion
I just ordered a box of Bosch HSS-G drill bits because they are marketed as being good for cutting metal.
But my woodturning chisels are also HSS - because the steel is soft but makes a sharp edge for a short while. If the drill bits are anything like them they'll go blunt at the first contact with metal. How can HSS do both?
But my woodturning chisels are also HSS - because the steel is soft but makes a sharp edge for a short while. If the drill bits are anything like them they'll go blunt at the first contact with metal. How can HSS do both?
Simpo Two said:
I just ordered a box of Bosch HSS-G drill bits because they are marketed as being good for cutting metal.
But my woodturning chisels are also HSS - because the steel is soft but makes a sharp edge for a short while. If the drill bits are anything like them they'll go blunt at the first contact with metal. How can HSS do both?
There are many types/grades of HSS dependant on their alloy contents and amounts. I your case the "G" only refers to how it's ground.But my woodturning chisels are also HSS - because the steel is soft but makes a sharp edge for a short while. If the drill bits are anything like them they'll go blunt at the first contact with metal. How can HSS do both?
I've said this till I'm blue in face - just buy these, use them at the right speed and feed and learn how to sharpen drills..........
https://ttp-hard-drills.com/?srsltid=AfmBOoofKeicq...
Simpo Two said:
dickymint said:
[I your case the "G" only refers to how it's ground
Yes, ground as opposed to rolled I believe.Good to know they're not made of cheese. They'll mainly be used on wood so should last ages.
Decent metal drills contain Cobalt - as in 'contain' Cobalt not just Cobalt coated. Pay the money, keep them sharp and unless you snap them they'll outlive you.
dickymint said:
They're ground at 135 degrees with a split point grind which is ideal for metals. Wood drills are better at 118 degrees. They will be 'ok' in wood but in my opinion quite cheesy in metal
So these Bosch HSS-G drills are not very good at either wood or metal? https://www.amazon.co.uk/dp/B008L099OEIt seems that 118 degree bits are called 'jobber' drills; should I get those instead? Links to a suitable set would be very helpful 'cos it's a jungle!
Simpo Two said:
dickymint said:
They're ground at 135 degrees with a split point grind which is ideal for metals. Wood drills are better at 118 degrees. They will be 'ok' in wood but in my opinion quite cheesy in metal
So these Bosch HSS-G drills are not very good at either wood or metal? https://www.amazon.co.uk/dp/B008L099OEIt seems that 118 degree bits are called 'jobber' drills; should I get those instead? Links to a suitable set would be very helpful 'cos it's a jungle!
For your needs I wouldn't get hung up on it all as those Bosch will be ok.
Caddyshack said:
mgtony said:
If you want drill bits for wood, why not buy a decent set of brad point bits?
I did think that myself.dickymint said:
No 'jobber' drills can be either angle. Personally I'd forget about the term 'jobber' as for some strange (to me) reason it's changed over time. As an apprentice we knew them as just general purpose drills. But now it seems to refer to longer drills
For your needs I wouldn't get hung up on it all as those Bosch will be ok.
OK, many thanks. My father had two sets of Dormer drills (letters and numbers) which I inherited and have used up until now, but they're really due for retirement now. Whilst I've tried sharpening drills, they never come out as good as they were. So I plan to use the new ones for most work, and just get the Dormers out for those 'in-between' sizes!For your needs I wouldn't get hung up on it all as those Bosch will be ok.
Any common or garden HSS bits are fine for mild steel and aluminium.
You start to need better drills for harder/tougher metals such as stainless steel.
Personally I use ordinary or coated HSS bits for ordinary drilling of most things.
I use cobalt bits for some stainless.
I don't use these 'best' drill bits for everyday stuff, because I want them kept sharp for the difficult work.
Stainless is a very variable thing, sometimes you can drill it really easily with ordinary bits, sometimes it laughs at cobalt bits.
If you've got to drill a really hard bit of stainless that's been work hardened, your options include carbide bits, annealing the work, grinding off the hard surface with a diamond burr...
Drill things in a drill press/pillar drill/milling machine if it's sensible, it gives the drill an easier life.
And use some lubricant/coolant for all but rough easy work, water is a lot better than nothing.
Ideally, get good at sharpening drill bits. (I'm working on that, still)
I buy packs of ten of the smaller sizes that I use a lot 2.5, 3, 4, 5, 6, so I've always got a sharp one.
I did buy a pack of 100 or so drills cheap on ebay, nice enough plastic box, drills mostly as blunt as a northern comedian.
You start to need better drills for harder/tougher metals such as stainless steel.
Personally I use ordinary or coated HSS bits for ordinary drilling of most things.
I use cobalt bits for some stainless.
I don't use these 'best' drill bits for everyday stuff, because I want them kept sharp for the difficult work.
Stainless is a very variable thing, sometimes you can drill it really easily with ordinary bits, sometimes it laughs at cobalt bits.
If you've got to drill a really hard bit of stainless that's been work hardened, your options include carbide bits, annealing the work, grinding off the hard surface with a diamond burr...
Drill things in a drill press/pillar drill/milling machine if it's sensible, it gives the drill an easier life.
And use some lubricant/coolant for all but rough easy work, water is a lot better than nothing.
Ideally, get good at sharpening drill bits. (I'm working on that, still)
I buy packs of ten of the smaller sizes that I use a lot 2.5, 3, 4, 5, 6, so I've always got a sharp one.
I did buy a pack of 100 or so drills cheap on ebay, nice enough plastic box, drills mostly as blunt as a northern comedian.
Simpo Two said:
OK, many thanks. My father had two sets of Dormer drills (letters and numbers) which I inherited and have used up until now, but they're really due for retirement now. Whilst I've tried sharpening drills, they never come out as good as they were. So I plan to use the new ones for most work, and just get the Dormers out for those 'in-between' sizes!
They may well be very good drills as in my day they were generally used for the correct tapping size holes in metal.I love a challenge so if you want to keep hold of them post them to me and I'll do my best to sort them out
dickymint said:
Simpo Two said:
OK, many thanks. My father had two sets of Dormer drills (letters and numbers) which I inherited and have used up until now, but they're really due for retirement now. Whilst I've tried sharpening drills, they never come out as good as they were. So I plan to use the new ones for most work, and just get the Dormers out for those 'in-between' sizes!
They may well be very good drills as in my day they were generally used for the correct tapping size holes in metal.I love a challenge so if you want to keep hold of them post them to me and I'll do my best to sort them out
I can find the modern versions - at £200-£300 a box! But when you consider they've lasted for 60 years of fairly intensive DIY across two generations, that's not bad at all.
Does anyone remember the Frhei drill bits that were sold at the Model Engineering Exhibition and tool fairs?
They were sold as being good for drilling through metal cutting files and all manner of otherwise hard to drill materials. I believe they had a carbide tip. It would be good to know what they actually were and if there is a current equivalent, as the company folded about ten years ago.
They were sold as being good for drilling through metal cutting files and all manner of otherwise hard to drill materials. I believe they had a carbide tip. It would be good to know what they actually were and if there is a current equivalent, as the company folded about ten years ago.
GliderRider said:
Does anyone remember the Frhei drill bits that were sold at the Model Engineering Exhibition and tool fairs?
They were sold as being good for drilling through metal cutting files and all manner of otherwise hard to drill materials. I believe they had a carbide tip. It would be good to know what they actually were and if there is a current equivalent, as the company folded about ten years ago.
We use solid carbide drills with holes in the webs to pump high pressure coolant through. There's an exact fomula for working out the spindle speed vs how fast to feed into the job, after crunching the numbers we usually think 'no chance!' but they cut and cut very well.They were sold as being good for drilling through metal cutting files and all manner of otherwise hard to drill materials. I believe they had a carbide tip. It would be good to know what they actually were and if there is a current equivalent, as the company folded about ten years ago.
How does a 3.7mm dia drill @ 5,700rpm feeding into 304 stainless steel @ 222mm/min sound?
Tango13 said:
How does a 3.7mm dia drill @ 5,700rpm feeding into 304 stainless steel @ 222mm/min sound?
Depending on the exact application we'd be asking our setter why its running so slow!0.2m/min isn't right, a good HSE drill will do 18m/min, much lower rpm. You should be doing 60-80 m/min in a through coolant carbide drill easily so I'd hope you have a decimal place or unit wrong.
Just in case you didn’t know how the coolant holes find their way into drill bits, AvE’s guide to coolant holes.
MyM2006 said:
Tango13 said:
How does a 3.7mm dia drill @ 5,700rpm feeding into 304 stainless steel @ 222mm/min sound?
Depending on the exact application we'd be asking our setter why its running so slow!0.2m/min isn't right, a good HSE drill will do 18m/min, much lower rpm. You should be doing 60-80 m/min in a through coolant carbide drill easily so I'd hope you have a decimal place or unit wrong.
I could push the feed slightly faster but the fractions of a second I would gain on the cycle time would all be lost with the cost of a new drill and the time spent replacing it.
Are you sure you're not confusing feed rates with surface speeds?
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