Drilling INTO carbide

[runnoahrun]

I need to drill several 3/8" to 3/4" inch holes through tungsten carbide up to 3/8" thick. Does anyone know of any options besides EDM? I'd like to keep this in house if I can.

[HuFlungDung]

I've heard that you can do it with a bowstring drill and some diamond dust, but I've never actually tried it

[RotarySMP]

Haven't done it but you might want to search the web for gemstone working groups.

Diamond dust, a copper tube, some oil, a drill press and lots of patience?

Please report back your successes and failures.

Regards,
Mark

[lerman]

First ;you have to pry the ring off your wife's hand. Bang on it with a hammer to break the diamond into dust. If you can survive that part, the rest is easy.

:-)

Ken

[ViperTX]

I'm not sure that the jewelery industry has core drills that are that large, you may end up making your own. You'll also need to create a border around the hole to keep the diamond slury in place...you'll probably need the coarsest you can find.

[runnoahrun]

I ordered some powder, when it gets here I'll try it with a copper tube on the drill press with a weight on the quill so I can leave it for a while. Spin it really slowly? I'll rig up something around to hold the diamond slurry in the area. Will 6" of copper tube last through 3/8 carbide? Is there anything else I should consider?

[ViperTX]

The diamond slury may be an oil or water based...so you'll need to continually brush the stuff down towards the cutting are...copper, not sure how long that will last...I would use steel tube.

[HuFlungDung]

Originally Posted by runnoahrun I ordered some powder, when it gets here I'll try it with a copper tube on the drill press with a weight on the quill so I can leave it for a while. Spin it really slowly? I'll rig up something around to hold the diamond slurry in the area. Will 6" of copper tube last through 3/8 carbide? Is there anything else I should consider?

Ya, post a message as soon as you get the first one done, if they still have internet then

[Zoff]

Oh! come on, just send it to EDM.

[runnoahrun]

First test run completed. I used 600 grit powder, a little oil and a drill press, 3/8 piece of brass, into RC96 WC. I didn't drill clear through but based on the surface area of the brass and the depth it went to after a certain amount of time I figured it is removing material at a rate of .000118 cu. in/min. Based on that it would take about 4 hours to drill 3/8" through a 1/4" piece. However, I figured that if I use a copper tube I would be coring it and not have to remonve as much volume I figure it would come out to just over 2 hours to drill a half inch hole. And I could fully automate the process too (put a pipe and some weight on the quill). I'm sure there will be different results over longer periods of time given that there will be carbide powder to deal with.
I read somewhere why they use brass and copper instead of something harder. Brass is more gummy than hard so it becomes embedded with the diamonds instead of being worn off. (kind of like the new guy filling the grinding wheel full of aluminum only reversed and resulting in what you want) There was less wear on the brass than the carbide.

Just a little FYI if anyone ever wants to try some abrasive drilling. I may not be dropping the EDM just yet bet I may rig up the unused drill press and try it for a few holes.

[keithorr]

Have you tried a diamond core drill? Come in sizes from subfractional to beyond 4 inch dia. Fix a water feed spindle to the chuck or arbor in a drill press. If you want to ask questions, try Starlite. I don't know if it is an appropriate solution to your problem. I do know the copper tube/diamond dust method is outdated.

http://www.starliteindustries.com/catlist.htm

[KiwiOS]

A diamond core drill probably won't last the distance. If you have a high speed spindle and TSC you can use a diamond end mill, like a core drill but solid on the bottom except for an off-centre hole down thru it for your "Thru Spindle Coolant". Hope this is making sence to you if you haven't seen them before. They are easy to get at any diamond tooling place. Let me know if you'd like more details. I have used this method everything from Silicon Nitride to Alumina to Zirconia.