Cutting Graphite
08-14-2003, 05:37 AM
#2
graphite is extremely abrasive. i like to use cutoff wheels whenever possible. i have also used router or milling bits, but they are expensive, and get fairly torn up in the process.
as far as the holes go, you obviously have to use a drill bit. get good ones wth a carbide coating and don't go too fast. heat will soften the bit and it will wear faster.
counter sinking can be done with a countersink bit, but again, it wears quickly. i prefer some type of stone that can be resurfaced as it will get a groove worn into it from plunging the same depth over and over again.
there was a great thread on this only a few weeks back. may have been started by davioh. i don't remember what it was called, but it was many posts long, and covered the gammut of things you'll be concerned about.
as far as the holes go, you obviously have to use a drill bit. get good ones wth a carbide coating and don't go too fast. heat will soften the bit and it will wear faster.
counter sinking can be done with a countersink bit, but again, it wears quickly. i prefer some type of stone that can be resurfaced as it will get a groove worn into it from plunging the same depth over and over again.
there was a great thread on this only a few weeks back. may have been started by davioh. i don't remember what it was called, but it was many posts long, and covered the gammut of things you'll be concerned about.
08-14-2003, 07:34 AM
#3
Tech Master
Dont forget to wear a mask while doing cutting graphite and stuff.
08-14-2003, 07:57 AM
#4
For doing countersink work in graphite I use a Dremel bit I think the number is 382... it's redish in color.
E
E
08-14-2003, 09:32 AM
#5
Tech Apprentice
First and foremost, carbon graphite is very, very dangerous stuff! Be very careful.
Fibers will be released during machining, drilling, sawing, sanding, etc. of the carbon graphite composites. These fibers, if inhaled, may lead to very serious respiratory problems.
You must use a respirator when working carbon graphite composites! Keep in mind that the carbon graphite fibers can have a diameter of < 1 µm, so make sure you get a very high quality respirator. (The common white dust masks are not sufficient)
Is addition to a respirator, working the carbon graphite composites under running water will prevent a lot of the carbon graphite fibers to become airborne. When possible, this is always how I work my carbon graphite composites.
Dremel tungsten carbide cutters do a great job of cutting the carbon graphite. For finishing, use a good file. Keep in mind that a file will dull quickly and be good for the garbage before you know it when working carbon graphite. Drilling holes, I have a preference for screw machine length drill bits, Cobalt steel, 135° self-centering point, great stuff, good clean holes. For counter sinking, use the Dremel 640 routing bit does a great job. It will dull, but you'll be able to get a good number of cuts before it needs replacing. In general, hand saws do not work all that well on carbon graphite. If you are cutting battery slots, remember to seal them with CA to prevent short circuits. Also, sealing the edges of a chassis will also reduce the risk of splintering the chassis.
Good Luck!
PS: An other option is just to draw you design in CAD and have a reputable machine shop cut it for you. This will cost more, but it may be a batter alternative.
Fibers will be released during machining, drilling, sawing, sanding, etc. of the carbon graphite composites. These fibers, if inhaled, may lead to very serious respiratory problems.
You must use a respirator when working carbon graphite composites! Keep in mind that the carbon graphite fibers can have a diameter of < 1 µm, so make sure you get a very high quality respirator. (The common white dust masks are not sufficient)
Is addition to a respirator, working the carbon graphite composites under running water will prevent a lot of the carbon graphite fibers to become airborne. When possible, this is always how I work my carbon graphite composites.
Dremel tungsten carbide cutters do a great job of cutting the carbon graphite. For finishing, use a good file. Keep in mind that a file will dull quickly and be good for the garbage before you know it when working carbon graphite. Drilling holes, I have a preference for screw machine length drill bits, Cobalt steel, 135° self-centering point, great stuff, good clean holes. For counter sinking, use the Dremel 640 routing bit does a great job. It will dull, but you'll be able to get a good number of cuts before it needs replacing. In general, hand saws do not work all that well on carbon graphite. If you are cutting battery slots, remember to seal them with CA to prevent short circuits. Also, sealing the edges of a chassis will also reduce the risk of splintering the chassis.
Good Luck!
PS: An other option is just to draw you design in CAD and have a reputable machine shop cut it for you. This will cost more, but it may be a batter alternative.
08-14-2003, 12:27 PM
#6
I concur with ARC... i have had respiratory problems since Feb 03 from cutting graphite chassis. I wore the white masks... but still had it in my sinuses when i was finished. I have since been fighting a serious case of sinusitis with a recurring upper respiratory infection (3 times). Its my bodys way of trying to remove the dust i inhaled. The money you would spend on the safety equipment (and doctors visits and medications) would be more than enough to pay for having a shop cut your design for you. Its no fun... 
- Dave
- Dave
08-15-2003, 03:48 PM
#10
Tech Addict
Where do you guys get your Carbon Fibre sheet from? I am trying to get some at the moment.
cya
Mike
cya
Mike
09-24-2015, 11:40 PM
#12
Tech Rookie
I cut my graphite on a band saw. I use a shop vac mounted as close to the blade cutting area as possible to suck up the dust. It' messy but not particularly harmful. I checked the MDS material data sheet and it says just that. It never hurts to avoid dust of any kind however and so I wear a dust mask. And wash up soon after working. The graphite can be cut easily but as others have said is very brittle. it is easily sanded and shaped. The xrdcarbon.com guys tell me it can be glued with various epoxies but if it is subject to much heat you need to get a high temp formula. These can be hard to find. You might email them for brands and availability. I used a high temp gasket sealer to glue a piece to a mount on my torch for a torch marver. So far I've not had a problem in several months. Screws and bolts work well but can be tricky to drill and tap; alignment must be very close and taps tend to cut oversize if you are not extremely careful. Use some sort of pillar tool to keep the tap straight. Sheet metal screws are very difficult as they tend to break out the hole while threading in.
09-25-2015, 05:56 AM
#13
I cut CF with a hacksaw. It's very easy to cut, very difficult to cut straight. I keep the blade wet to avoid dust but also for lubrication which keeps heat down so it doesn't ruin the blade prematurely. I finish with wet sandpaper.
I use normal HSS drill bits again with water (usually just a drop on top of the plate before drilling is enough) in a power screwdriver (for very low rotating speed - I think mine does about 220 rpm or some such) with good torque. Bits last very well.
The same can not be said about countersink tools. I use them in the same driver for the same reasons. The worst problem is to make sure the countersink is perfectly centred on the hole. There are tools that drill and countersink in one go but a good quality one is more than a new chassis on its own. The countersink part of it wears just as quickly as a countersink tool, but the countersink is perfectly centred. I guess it would be cheaper to get a drill press if I had where to keep it.
Countersinking is by far the most boring job ever and takes forever. You can also use centering bits for countersinking, but they don't have the correct angle, so you still need to finish it with a c/s tool.
I use normal HSS drill bits again with water (usually just a drop on top of the plate before drilling is enough) in a power screwdriver (for very low rotating speed - I think mine does about 220 rpm or some such) with good torque. Bits last very well.
The same can not be said about countersink tools. I use them in the same driver for the same reasons. The worst problem is to make sure the countersink is perfectly centred on the hole. There are tools that drill and countersink in one go but a good quality one is more than a new chassis on its own. The countersink part of it wears just as quickly as a countersink tool, but the countersink is perfectly centred. I guess it would be cheaper to get a drill press if I had where to keep it.
Countersinking is by far the most boring job ever and takes forever. You can also use centering bits for countersinking, but they don't have the correct angle, so you still need to finish it with a c/s tool.
09-25-2015, 06:11 AM
#14
I cut it with a dremel and a metal cutting disc.
I drill it with cheap drill bits (3 pieces for 2 euro)
Also the countersink is done wit cheap bits from the local hardware store
I drill it with cheap drill bits (3 pieces for 2 euro)
Also the countersink is done wit cheap bits from the local hardware store
09-25-2015, 10:26 AM
#15
I concur with ARC... i have had respiratory problems since Feb 03 from cutting graphite chassis. I wore the white masks... but still had it in my sinuses when i was finished. I have since been fighting a serious case of sinusitis with a recurring upper respiratory infection (3 times). Its my bodys way of trying to remove the dust i inhaled. The money you would spend on the safety equipment (and doctors visits and medications) would be more than enough to pay for having a shop cut your design for you. Its no fun...