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Diamond tip burs and twist drills


#1

I have never used twist drills or burs that have been diamond
tipped. What uses are appropriate (and inappropriate)? Special
coolants needed? How long do they last?

Thanks,
Jamie


#2

Turner Tooling in New Hampshire has a wide range of good products at
good prices. (owner is my cousin in law, David Hunter re full
discIosure). I use diamond tools on stones and organics, not metals.
I use plain water as a lubricant. I clean the tools in water and wipe
on cloth or paper towel frequently.

Marianne Hunter


#3

I haven’t found them particularly suitable for soft metals, gold
etc. I have used dia drills for removing broken burs or twist drills
though, takes a steady hand. For working stone they are terrific if
you keep them cool.

The difference between dia and steel tools is that diamond abrades
and steel shears. I think I get better feel with shearing than
abrading, but that might be because that’s what I’ve always done. For
example…they don’t make them but if they did, take setting burs, an
abrasive tool would require frequent stops to check progress and
alignment. With a steel tool you can feel when its right and when its
not. Most times you can cut a seat with a steel tool in about 3
seconds and know its right because you get feedback via vibrations
and pull. An abrasive tool could just wander and you wouldn’t feel
it.


#4

I thought I would wait this out and see what others have to say
first.

I am a practicing dentist and in the mouth I use both the diamond
and carbide burs, but keep in mind that I am sometimes running at
400,000 RPM and always using water as a coolant. I do not apply much
pressure: a very light touch is all that is needed. I am cutting
porcelain, gold, mercury-silver amalgam, and sometimes something that
feels like stainless steel, as well as tooth structure. Keep in mind
that I have spent a lot of practice time learning to control this
awesome drill.

Cutting metal with a carbide bur sometimes leads to the bur jumping
off of the metal and kicking back. When I cut off an old crown I
usually use a diamond for less vibration and better control. A
milling machine would be very rigid and probably never use a diamond
bur except for ceramic materials and perhaps some super hard metals.
The carbide would cut much faster. When I am the jeweler or metal
fabricator I like the carbides and I am prepared for the kickbacks.

Cleaning and carving soft gemstones such as opal can easily be done
with a slow handpiece: either a flexshaft machine or and electric
handpiece. Diamond burs give a good feel for removing sand and doing
the rough and fine shaping.

Removing stuck or broken taps or screws can be done with a high
speed handpiece and carbide burs and lots of patience, and lots of
burs. Sometimes a very small (less than.5mm diameter) bur is the only
one to get into a very tight spot so as not to damage the piece you
are trying to save.

Running the diamonds and carbides with coolant really shortens the
lifespan of the bur, sometime to only a few seconds!

Charles Friedman DDS
Ventura by the Sea


#5

I would use diamond only for stone and diamond tipped twist drills
would be useless.

Twist drills need to be more precise than diamond will allow. Always
use a coolant with diamond; water is adequate. Length of service
depends on the quality of user.

KPK


#6
Running the diamonds and carbides with coolant really shortens the
lifespan of the bur, sometime to only a few seconds! 

Did you mean without coolant?

Al Balmer
Sun City, AZ


#7
A milling machine would be very rigid and probably never use a
diamond bur except for ceramic materials and perhaps some super
hard metals. 

It is the nature of diamond abrasives that they work best on
materials of a certain hardness and above - can’t say what a number
would be, but it’s true. That’s the reason why you can get right up
on a diamond trim saw and not cut yourself - yes, the rotating disk
is bad for you, though. Your fingers are too soft for the diamond to
cut. It doesn’t mean that you ~can’t~ use them on gold or silver, but
they are intended for steels, stone and ceramics, where they
function best.


#8

Kevin,

Not all diamond tools use diamond dust as an abrasive. Some use a
polycrystalline diamond insert as a sharp cutting edge. Others use
vapor-deposired diamond coatings.

Polycrystalline diamond tipped twist drills are very widely and
successfully used in many industries. Here is one example of a
source:

http://tinyurl.com/ydgp62t

Vapor-deposited diamond films are also used for very wear-resistant
drill bits. See:

http://tinyurl.com/ygy6ssc

I agree that diamond dust twist drills would "miss the point"
somewhat.

Mark B
Fourth Axis
http://www.fourth-axis.com/tilt-motor-mount/