The Straight Dope

Go Back   Straight Dope Message Board > Main > General Questions

Reply
 
Thread Tools Display Modes
  #1  
Old 09-11-2010, 02:06 PM
bardos bardos is offline
Guest
 
Join Date: Feb 2003
What exactly are "diamond-tipped" drill bits?

For drilling brick or stone, these are the bits I use, often called diamond tipped bits. Do they have anything to do with diamonds?
Reply With Quote
Advertisements  
  #2  
Old 09-11-2010, 02:12 PM
lazybratsche lazybratsche is offline
Guest
 
Join Date: Feb 2006
Well, they're probably actually tipped with little diamonds. Industrial diamond isn't very expensive, and it's the hardest abrasive available, so it's used for all sorts of tools. Diamond cutting tools are especially good for masonry.
Reply With Quote
  #3  
Old 09-11-2010, 02:14 PM
Sage Rat Sage Rat is offline
Member
 
Join Date: Mar 2004
Location: Howdy
Posts: 17,730
Yes, small diamonds are embedded or coated on to aid in cutting through very hard materials.

http://en.wikipedia.org/wiki/Drill_bit#Materials
Reply With Quote
  #4  
Old 09-11-2010, 02:18 PM
Broomstick Broomstick is online now
Charter Member
 
Join Date: Mar 2001
Location: NW Indiana
Posts: 24,442
Yes, diamond tipped drill bits really do have itty-bitty diamonds on them. Look closely at one. See the teeny-weeny black gritty bits? Those are real diamonds. They're industrial grade diamonds, which don't look like the gem quality ones, but they're still diamonds and still hard.

There also diamond grit sanders.

(Standard alumina oxide sandpaper could be said to be "ruby" or "sapphire" grit - again, it's the same stuff, but industrial rather than gem quality.)
Reply With Quote
  #5  
Old 09-11-2010, 04:06 PM
Chronos Chronos is online now
Charter Member
Moderator
 
Join Date: Jan 2000
Location: The Land of Cleves
Posts: 68,155
While we're at it, carbide tools are made of silicon carbide, a material very similar to diamond (basically, diamond with half the carbon atoms replaced by silicon). It's not quite as hard as diamond, but it's still pretty hard, and much cheaper and easier to make tools out of.
__________________
Time travels in divers paces with divers persons.
--As You Like It, III:ii:328
Check out my dice in the Marketplace
Reply With Quote
  #6  
Old 09-11-2010, 04:10 PM
bardos bardos is offline
Guest
 
Join Date: Feb 2003
You folks are fantastic with all this information. Thanks.
Reply With Quote
  #7  
Old 09-11-2010, 04:23 PM
Magiver Magiver is offline
Guest
 
Join Date: Apr 2003
Quote:
Originally Posted by Chronos View Post
While we're at it, carbide tools are made of silicon carbide, a material very similar to diamond (basically, diamond with half the carbon atoms replaced by silicon). It's not quite as hard as diamond, but it's still pretty hard, and much cheaper and easier to make tools out of.
And when drilling masonry it is more useful to use a hammer drill than to have a diamond tipped drill. If diamond tipped drills are expensive then the money should be invested in the drill for any serious work.

Last edited by Magiver; 09-11-2010 at 04:24 PM..
Reply With Quote
  #8  
Old 09-11-2010, 04:52 PM
beowulff beowulff is offline
Member
 
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 14,297
Quote:
Originally Posted by Chronos View Post
While we're at it, carbide tools are made of silicon carbide, a material very similar to diamond (basically, diamond with half the carbon atoms replaced by silicon). It's not quite as hard as diamond, but it's still pretty hard, and much cheaper and easier to make tools out of.
I don't think so.
Most drills are actually tipped with Tungsten Carbide. Silicon Carbide is much too brittle, and can't be brazed like WC can.
Reply With Quote
  #9  
Old 09-11-2010, 05:30 PM
Chronos Chronos is online now
Charter Member
Moderator
 
Join Date: Jan 2000
Location: The Land of Cleves
Posts: 68,155
I stand corrected.
Reply With Quote
  #10  
Old 09-11-2010, 05:44 PM
BrotherCadfael BrotherCadfael is offline
Guest
 
Join Date: Feb 2003
So, basically, a diamond-tipped drill bit is a diamond-tipped drill bit.
Reply With Quote
  #11  
Old 09-11-2010, 06:21 PM
Chefguy Chefguy is offline
Charter Member
 
Join Date: Jun 2003
Location: Portlandia
Posts: 37,188
Quote:
Originally Posted by BrotherCadfael View Post
So, basically, a diamond-tipped drill bit is a diamond-tipped drill bit.
That's all you took away from this?
Reply With Quote
  #12  
Old 09-16-2010, 10:29 AM
Bongmaster Bongmaster is offline
Guest
 
Join Date: Oct 2002
SO how do they secure the diamonds to the tip? Some kind of diamond glue? Wouldn't it need to be just as hard?
Reply With Quote
  #13  
Old 09-16-2010, 10:51 AM
beowulff beowulff is offline
Member
 
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 14,297
Quote:
Originally Posted by Bongmaster View Post
SO how do they secure the diamonds to the tip? Some kind of diamond glue? Wouldn't it need to be just as hard?
Usually, the diamonds are embedded in a metal matrix. The metal wears away, exposing the diamonds. I'm not sure how they actually make the diamond-metal matrix (I don't know if the diamonds and powered metal are applied to the drill as a paste, and then baked on, for example), and I'm sure that many process are trade secrets.
Reply With Quote
  #14  
Old 09-16-2010, 11:10 AM
pravnik pravnik is offline
Member
 
Join Date: Apr 2002
Location: TX
Posts: 13,386
Note that while the drill bits are actually encrusted with diamonds, giving your wife a set for your anniversary does not produce the desired effect.
Reply With Quote
  #15  
Old 09-16-2010, 01:10 PM
TriPolar TriPolar is offline
Guest
 
Join Date: Oct 2007
Various bonding techniques are used. Sodium silicate bonding is one technique. Cobalt-carbide combinations are often combined in powdered form (sintering), and then bonded to the drill bit. Sometimes diamond dust is bonded using conventional high temperature adhesives, and the drill bits must be kept cool during drilling operations.

I also recommend against diamond tipped tools as anniversary presents for your wife. Gifts to me of that kind are appreciated though.
Reply With Quote
  #16  
Old 09-16-2010, 01:26 PM
Hari Seldon Hari Seldon is offline
Guest
 
Join Date: Mar 2002
I believe that there is a sintering process whereby a mixture of diamond and a metal is fused onto a blank. There was an earlier process (that my father helped develop in the US, see below) of electroplating onto the blank. Basically, you surrounded the blank drill or disk with a basket of diamond dust, immersed the whole into a solution of nickel sulfate, put one electrode on a hunk of nickel and the other on the drills or disk and turned on the current. Obviously, there are a lot of details I've omitted (one thing I do recall is that you needed three times the current density needed for ordinary nickel plating because the diamonds interfered with the plating. Anyway, you did this for a while (a day or so, IIRC) and, voila, the blank was covered with an incrustation of a diamond/nickel matrix. The same process was used later for Revlon's "diamond coated nail files" but I believe the percentage of diamond was low and some other grit was used mainly.

My father was working for a company that made dental equipment (picks, mirrors, that sort of thing) in the late 30s. Diamond dental drills all came from Germany. With war imminent, it looked as though the supply would be cut off--as indeed it was--and the owner of the company decided they could make a fortune if they could work out a process--he was right. At any rate, my father was one of the people who developed this electroplating process. They kept it as an industrial secret--no patent--and later branched out into industrial tools, grinding wheels and "core drills", in which the blank was punched out after the shell was guilt. Corning Glass bought zillions of them.

Incidentally, for esthetic reasons, they used white diamond dust for the dental drills. Also for Revlon, I think. White dust may have cost more than black, but there aren't any uses for it in jewelry, so it probably wasn't that much more.
Reply With Quote
  #17  
Old 09-16-2010, 02:18 PM
Broomstick Broomstick is online now
Charter Member
 
Join Date: Mar 2001
Location: NW Indiana
Posts: 24,442
I think white diamond dust is a byproduct of gem production (when you grind diamonds you use diamond dust and wind up with even more diamond dust) so it may not be that expensive, though probably more than the darker varieties.
Reply With Quote
  #18  
Old 09-16-2010, 03:01 PM
Keeve Keeve is offline
Guest
 
Join Date: Aug 2000
What I still don't understand is this: If the material they use for attaching the dust is so strong, why not just use that for the drill bit? Why bother with the diamond dust at all? Is it just marketing?
Reply With Quote
  #19  
Old 09-16-2010, 03:40 PM
purplehorseshoe purplehorseshoe is offline
Guest
 
Join Date: Jun 2009
'Cuz it's not as abrasive. Just a strong bond-er. (That'd be the technical term.)
Reply With Quote
  #20  
Old 09-16-2010, 04:00 PM
Broomstick Broomstick is online now
Charter Member
 
Join Date: Mar 2001
Location: NW Indiana
Posts: 24,442
It's like asking why, if sandpaper is grit glued to paper, they don't just sell you glue-covered paper. It's the grit that does the job. Likewise for diamond-tipped bits - it's the diamond grit that does the job, not the stuff holding the grit on no matter how strong it is.
Reply With Quote
  #21  
Old 09-16-2010, 04:04 PM
YamatoTwinkie YamatoTwinkie is online now
Guest
 
Join Date: Apr 2008
Quote:
Originally Posted by Keeve View Post
What I still don't understand is this: If the material they use for attaching the dust is so strong, why not just use that for the drill bit? Why bother with the diamond dust at all? Is it just marketing?
If the plastic handle they use to attach a steel knife blade to is so strong, why not just use that for the knife blade? Why bother with steel at all? Is it just marketing?
Reply With Quote
  #22  
Old 09-16-2010, 04:14 PM
Keeve Keeve is offline
Guest
 
Join Date: Aug 2000
I had been wondering about that for years, and suddenly, I can't even figure out what I was thinking!

Ignorance has been fought. Thanks!
Reply With Quote
  #23  
Old 09-16-2010, 04:14 PM
TriPolar TriPolar is offline
Guest
 
Join Date: Oct 2007
Quote:
Originally Posted by YamatoTwinkie View Post
Quote:
Originally Posted by Keeve View Post
What I still don't understand is this: If the material they use for attaching the dust is so strong, why not just use that for the drill bit? Why bother with the diamond dust at all? Is it just marketing?
If the plastic handle they use to attach a steel knife blade to is so strong, why not just use that for the knife blade? Why bother with steel at all? Is it just marketing?

Why don't they make the whole plane out of the stuff the 'black box' is made of?
Reply With Quote
  #24  
Old 09-16-2010, 05:41 PM
Broomstick Broomstick is online now
Charter Member
 
Join Date: Mar 2001
Location: NW Indiana
Posts: 24,442
The roads aren't wide enough - Cecil covered it in a column some time ago.
Reply With Quote
  #25  
Old 09-16-2010, 08:19 PM
TriPolar TriPolar is offline
Guest
 
Join Date: Oct 2007
Quote:
Originally Posted by Broomstick View Post
The roads aren't wide enough - Cecil covered it in a column some time ago.
Ignorance fought. Now I have to cancel all that black box material I ordered.
Reply With Quote
  #26  
Old 09-17-2010, 08:14 AM
muldoonthief muldoonthief is online now
Member
 
Join Date: Jul 2003
Location: North of Boston
Posts: 9,435
Quote:
Originally Posted by beowulff View Post
Quote:
Originally Posted by Chronos View Post
While we're at it, carbide tools are made of silicon carbide, a material very similar to diamond (basically, diamond with half the carbon atoms replaced by silicon). It's not quite as hard as diamond, but it's still pretty hard, and much cheaper and easier to make tools out of.
I don't think so.
Most drills are actually tipped with Tungsten Carbide. Silicon Carbide is much too brittle, and can't be brazed like WC can.
Tungsten carbide drills? What the bloody hell are tungsten carbide drills?
Reply With Quote
  #27  
Old 09-17-2010, 08:39 AM
CutterJohn CutterJohn is offline
Guest
 
Join Date: Nov 2007
Quote:
Originally Posted by muldoonthief View Post
Quote:
Originally Posted by beowulff View Post

I don't think so.
Most drills are actually tipped with Tungsten Carbide. Silicon Carbide is much too brittle, and can't be brazed like WC can.
Tungsten carbide drills? What the bloody hell are tungsten carbide drills?
Drills where the cutting edge is made of a tungsten carbide. Very hard stuff, and keeps a great edge. Goes through plain old steel like butter. Most of the bit is tool steel.. Just the edge is tungsten carbide.
Reply With Quote
  #28  
Old 09-17-2010, 08:45 AM
muldoonthief muldoonthief is online now
Member
 
Join Date: Jul 2003
Location: North of Boston
Posts: 9,435
Quote:
Originally Posted by CutterJohn View Post
Quote:
Originally Posted by muldoonthief View Post

Tungsten carbide drills? What the bloody hell are tungsten carbide drills?
Drills where the cutting edge is made of a tungsten carbide. Very hard stuff, and keeps a great edge. Goes through plain old steel like butter. Most of the bit is tool steel.. Just the edge is tungsten carbide.
"Drills where the cutting edge is made of a tungsten carbide" ? You've bloody fancy talk since you left London.
Reply With Quote
  #29  
Old 09-17-2010, 08:46 AM
Hari Seldon Hari Seldon is offline
Guest
 
Join Date: Mar 2002
Quote:
Originally Posted by Keeve View Post
What I still don't understand is this: If the material they use for attaching the dust is so strong, why not just use that for the drill bit? Why bother with the diamond dust at all? Is it just marketing?
Aside from the other replies let me point out that the bonding agent in the electroplating process I described is pure nickel, not even a very strong material. They also occasionally used cobalt although I never knew why.

I don't know where the diamond dust came from, but back in the 60s, white dust cost about $5 a carat, $25 a gram, $750 an ounce. But it didn't take much.

There were other drills made without diamonds and I think they were tungsten carbide.
Reply With Quote
  #30  
Old 09-17-2010, 09:08 AM
Ale Ale is online now
Guest
 
Join Date: May 2003
Quote:
Originally Posted by CutterJohn View Post
Quote:
Originally Posted by muldoonthief View Post

Tungsten carbide drills? What the bloody hell are tungsten carbide drills?
Drills where the cutting edge is made of a tungsten carbide. Very hard stuff, and keeps a great edge. Goes through plain old steel like butter. Most of the bit is tool steel.. Just the edge is tungsten carbide.
I have many micro drill and miller bits made entirely out of tungsten carbide, they go through anything but you just drop them on the floor and they snap in pieces. That's why your normal drill bits are not made entirely out of that material. That and it's bloody expensive too.

Last edited by Ale; 09-17-2010 at 09:10 AM..
Reply With Quote
  #31  
Old 09-20-2010, 02:07 AM
Darth Nader Darth Nader is offline
Member
 
Join Date: Dec 2000
Location: Deep blue Tejas
Posts: 3,167
I'm very glad that my tungsten carbide wedding ring isn't diamond-tipped. Can you imagine the damage it would do when I move it up and then out of my nose?

Click here if you think I'm posting on acid.
Reply With Quote
Reply



Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 10:21 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright 2017 Sun-Times Media, LLC.