nbk2000
January 25th, 2003, 05:32 AM
During further research into safe cracking, the use of diamond core drill bits came to my attention.
These are hollow tubes that have an arbor on one end, and are crusted with diamonds on the other.
In use, the coring bit grinds a circular hole through ANY material known to man, be it carbide ceramic...titanium hardplate...anything.
While grinding through the material, though, it generates a LOT of heat. This heat has to be carried away, otherwise the drill bit will "burn", destroying the diamonds and the binder that holds them onto the bit.
The usual means of cooling the bit is to maintain a continuous flow of water on the bit.
While this is easy enough to do while you're working on something in a legit business, it's a little harder to do when drilling into a jewlery store safe in the middle of the night, there not being many water taps (or drains) available for this purpose.
Also, during normal core drilling with water cooling, the water tends to get flung about by the centrifigual action of the spinning drill bit. This is not only messy, but dangerous, since standing in a puddle of water while holding an electric drill is not conducive to long life. <img border="0" title="" alt="[Wink]" src="wink.gif" />
So, to alleviate these problems, the idea of a self-contained recirculating cooling system, came to mind.
<img src="http://nbk2000.freeyellow.com/Drill_Shield.jpg" alt=" - " />
A bowl (like a mixing bowl) is affixed to the target, using any needed means, and the edges sealed in a watertight fashion. The bottom has been cut out of the bowl, leaving an open ended hemispherical chamber attached to the target.
The coring bit has a disc (green) attached to it that fits over the arbor, and is held in place by the drill chuck. This disc is just small enough to fit through the open hole of the bowl.
As the hole is drilled, the fluid flows along the coring bit, where it meets with the disc, and is thrown off to impact on the bowl, where it then flows down to be collected.
Two nipples have been attached to the bowl. The one at the top is a spray nozzle that directs the cooling fluid onto the coring bit. The nipple at the bottom, where the fluid collects, to be drained off.
The fluid used could be either straight water or, preferably, ethylene glycol or some other non-toxic/non-flammable/non-conductive fluid.
The fluid is drained off as it collects, pulled through a filter to remove debris, then recirculated back via electric pump, onto the coring bit, in a continuous cycle.
The way that the fluid is kept cool is through a heat exchanger attached to a liquid CO<sub>2</sub> tank, like that used to carbonate sodas. A small flow of CO<sub>2</sub> is continuously released which absorbs the heat from the coolant fluid as it evaporates.
The entire assembly would be fitted onto a small cart, like that used to tote around oxygen tanks, for easy transportation to the scene of the crime.
Because of the near-dry work enviroment that this setup provides for the person using it, the work would progress in a much neater, safer, and possibly faster, manner.
I'm sure someone more mechanically inclined could design a much more compact system that'd slide right over the bit itself.
<small>[ January 25, 2003, 04:33 AM: Message edited by: nbk2000 ]</small>
These are hollow tubes that have an arbor on one end, and are crusted with diamonds on the other.
In use, the coring bit grinds a circular hole through ANY material known to man, be it carbide ceramic...titanium hardplate...anything.
While grinding through the material, though, it generates a LOT of heat. This heat has to be carried away, otherwise the drill bit will "burn", destroying the diamonds and the binder that holds them onto the bit.
The usual means of cooling the bit is to maintain a continuous flow of water on the bit.
While this is easy enough to do while you're working on something in a legit business, it's a little harder to do when drilling into a jewlery store safe in the middle of the night, there not being many water taps (or drains) available for this purpose.
Also, during normal core drilling with water cooling, the water tends to get flung about by the centrifigual action of the spinning drill bit. This is not only messy, but dangerous, since standing in a puddle of water while holding an electric drill is not conducive to long life. <img border="0" title="" alt="[Wink]" src="wink.gif" />
So, to alleviate these problems, the idea of a self-contained recirculating cooling system, came to mind.
<img src="http://nbk2000.freeyellow.com/Drill_Shield.jpg" alt=" - " />
A bowl (like a mixing bowl) is affixed to the target, using any needed means, and the edges sealed in a watertight fashion. The bottom has been cut out of the bowl, leaving an open ended hemispherical chamber attached to the target.
The coring bit has a disc (green) attached to it that fits over the arbor, and is held in place by the drill chuck. This disc is just small enough to fit through the open hole of the bowl.
As the hole is drilled, the fluid flows along the coring bit, where it meets with the disc, and is thrown off to impact on the bowl, where it then flows down to be collected.
Two nipples have been attached to the bowl. The one at the top is a spray nozzle that directs the cooling fluid onto the coring bit. The nipple at the bottom, where the fluid collects, to be drained off.
The fluid used could be either straight water or, preferably, ethylene glycol or some other non-toxic/non-flammable/non-conductive fluid.
The fluid is drained off as it collects, pulled through a filter to remove debris, then recirculated back via electric pump, onto the coring bit, in a continuous cycle.
The way that the fluid is kept cool is through a heat exchanger attached to a liquid CO<sub>2</sub> tank, like that used to carbonate sodas. A small flow of CO<sub>2</sub> is continuously released which absorbs the heat from the coolant fluid as it evaporates.
The entire assembly would be fitted onto a small cart, like that used to tote around oxygen tanks, for easy transportation to the scene of the crime.
Because of the near-dry work enviroment that this setup provides for the person using it, the work would progress in a much neater, safer, and possibly faster, manner.
I'm sure someone more mechanically inclined could design a much more compact system that'd slide right over the bit itself.
<small>[ January 25, 2003, 04:33 AM: Message edited by: nbk2000 ]</small>