Anyone know why you can't buy diamond drills - I have a diamond saw but the
hardest drill I have is HSS Cobolt?

Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw but the
hardest drill I have is HSS Cobolt?



Because diamonds "grind" rather than "chisel".

For drilling stone, there would be no advantage to making a diamond
drill over a TCT drill and it would be a lot more expensive.

For drilling wood or steel, the grinding action of a diamond drill would
be inefficient compared with a tool that cuts ("chisels"). Now, if you
could make a solid diamond tip for a drill and put a cutting edge on it,
that would be awesome (assuming it wasn't too brittle to be of any use).

"Dave Osborne" wrote in message
...
Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw but
the hardest drill I have is HSS Cobolt?

Because diamonds "grind" rather than "chisel".

For drilling stone, there would be no advantage to making a diamond drill
over a TCT drill and it would be a lot more expensive.

You can buy diamond core drills, which, as Dave says, grind their way
through. Beneficial for large holes in stone but that's about all.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

Dave Osborne wrote:
Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw
but the hardest drill I have is HSS Cobolt?


Because diamonds "grind" rather than "chisel".


eh? I have diamond drills for tiles and stone..brilliant.

The Medway Handyman wrote:
"Dave Osborne" wrote in message
...
Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw but
the hardest drill I have is HSS Cobolt?
Because diamonds "grind" rather than "chisel".

For drilling stone, there would be no advantage to making a diamond drill
over a TCT drill and it would be a lot more expensive.

You can buy diamond core drills, which, as Dave says, grind their way
through. Beneficial for large holes in stone but that's about all.



Good point, well made. Although, just to be clear, I was rather thinking
of a solid drill rather than a core drill (which I was think of as a
saw, rather than a drill). :-)

"Dave Osborne" wrote in message
...
The Medway Handyman wrote:
"Dave Osborne" wrote in message
...
Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw but
the hardest drill I have is HSS Cobolt?
Because diamonds "grind" rather than "chisel".

For drilling stone, there would be no advantage to making a diamond
drill over a TCT drill and it would be a lot more expensive.

You can buy diamond core drills, which, as Dave says, grind their way
through. Beneficial for large holes in stone but that's about all.



Good point, well made. Although, just to be clear, I was rather thinking
of a solid drill rather than a core drill (which I was think of as a saw,
rather than a drill). :-)

Which it is if you think about it.

We have a local diamond drilling firm called Rajinda & Sons. The slogan on
their vans says "You've tried the cowboys, now try the Indians" :-)

--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

The Medway Handyman wrote:
"Dave Osborne" wrote in message
...
The Medway Handyman wrote:
"Dave Osborne" wrote in message
...
Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw but
the hardest drill I have is HSS Cobolt?
Because diamonds "grind" rather than "chisel".

For drilling stone, there would be no advantage to making a diamond
drill over a TCT drill and it would be a lot more expensive.
You can buy diamond core drills, which, as Dave says, grind their way
through. Beneficial for large holes in stone but that's about all.


Good point, well made. Although, just to be clear, I was rather thinking
of a solid drill rather than a core drill (which I was think of as a saw,
rather than a drill). :-)

Which it is if you think about it.

We have a local diamond drilling firm called Rajinda & Sons. The slogan on
their vans says "You've tried the cowboys, now try the Indians" :-)


lol :-P

On 10/10/2010 11:40, Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw but the
hardest drill I have is HSS Cobolt?

There are 3 drills harder than that, but you will have a hell a lot of
trouble tracking them down. Even Dormer do do not list them.

C1150 come next with
D200 following
Solid tungsten carbide was used for drilling carbon fibre.

Dave

On Oct 10, 12:05*pm, Dave Osborne wrote:
Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw but the
hardest drill I have is HSS Cobolt?

Because diamonds "grind" rather than "chisel".

For drilling stone, there would be no advantage to making a diamond
drill over a TCT drill and it would be a lot more expensive.

For drilling wood or steel, the grinding action of a diamond drill would
* be inefficient compared with a tool that cuts ("chisels"). Now, if you
could make a solid diamond tip for a drill and put a cutting edge on it,
that would be awesome (assuming it wasn't too brittle to be of any use).

It would be too brittle. The way to make practical hard material bits
is to embed little pieces of the stuff in a softer matrix. That gives
he hard cutting material plus the slight flex of the softer stuff,
thus eliminating the brittleness.

Diamond drills do exist, but for wood they're just not necessary. A
properly designed bit will do a fine job - unfortunately many are
still struggling along with ill suited bits like twist drills.


NT

Dave wrote:
On 10/10/2010 11:40, Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw
but the
hardest drill I have is HSS Cobolt?

There are 3 drills harder than that, but you will have a hell a lot of
trouble tracking them down. Even Dormer do do not list them.

C1150 come next with
D200 following
Solid tungsten carbide was used for drilling carbon fibre.

Dave


Good point. You can buy solid carbide drills for drilling printed
circuit boards.

http://www.megauk.com/carbide_drill_bits.php

"Dave Osborne" wrote in message
...
Dave wrote:
On 10/10/2010 11:40, Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw but
the
hardest drill I have is HSS Cobolt?

There are 3 drills harder than that, but you will have a hell a lot of
trouble tracking them down. Even Dormer do do not list them.

C1150 come next with
D200 following
Solid tungsten carbide was used for drilling carbon fibre.

Dave


Good point. You can buy solid carbide drills for drilling printed circuit
boards.

http://www.megauk.com/carbide_drill_bits.php

which always sounds odd because pcbs don't seem that hard - but I suppose
they are full of glass these days...

S

Spamlet wrote:
"Dave Osborne" wrote in message
...
Dave wrote:
On 10/10/2010 11:40, Will wrote:
Anyone know why you can't buy diamond drills - I have a diamond saw but
the
hardest drill I have is HSS Cobolt?
There are 3 drills harder than that, but you will have a hell a lot of
trouble tracking them down. Even Dormer do do not list them.

C1150 come next with
D200 following
Solid tungsten carbide was used for drilling carbon fibre.

Dave

Good point. You can buy solid carbide drills for drilling printed circuit
boards.

http://www.megauk.com/carbide_drill_bits.php

which always sounds odd because pcbs don't seem that hard - but I suppose
they are full of glass these days...

S



Yes, the common professional quality board is FR-4, which is made of
layers of glass fibre mat impregnated with epoxy resin.

http://en.wikipedia.org/wiki/Fr4

The thing about drilling circuit boards is that you need the hole to be
perfect every time. Commercially, boards are drilled clamped between
sacrificial substrates so that there is no surface spalling on entry or
exit. Also, they drill at very high speed, so as soon as the sharpness
of the drill goes off, it tends to burn its way through. PCB drills have
a limited life because of the glass content in the PCB, but solid
carbide drills lasts much longer than HSS.