Diamonds will cut just about anything. The trick is matching the matrix holding the diamond bits to the material being cut. I have dealt with diamond drilling quite a bit in my profession (mining of industrial minerals). The harder the materials to be cut, often the better the diamonds like it provided the matrix wears out slightly faster than the diamonds to prevent faceting of the exposed bits. Always want to prevent polishing of the diamonds. Saw this in upstate New York gneiss where a crew drilled 300 feet in 12 hours with an NQ bit (75.7mm dia with a 10.5mm thick annulus). Normal rates are 100-175ft in a 12 hour shift. This included punching through several seams of magnetite. I would be more worried about trying to cut aluminum where it would likely cold weld the bit with or without water.
In drilling rock, water is key. While I have not seen it, I have heard the drillers talk of welding the drillbit to the end of the hole several hundred to thousands of feet downhole when they lost water circulation. When that happens the pull out whatver part of the drilling head they can, send a new bit downhole and drill through the parts stuck in the hole and keep on trucking. On Tue, May 10, 2016 at 6:02 PM, Dave Cole <[email protected]> wrote: > On 5/10/2016 2:56 PM, Gene Heskett wrote: > > On Tuesday 10 May 2016 11:47:13 Dave Cole wrote: > > > >> I've been doing the controls for a manufacturer of large core drill > >> machines for about 10 years. The machines are made to drill holes in > >> concrete structures that make up sewer systems. > >> The machines can drill up to 60" holes using diamond segmented tipped > >> bits. > >> > >> Diamond bits work great for concrete and stone and they do ok when > >> sawing through the wire reinforcement in the concrete as well (up to > >> about 1/2" rebar reinforcement). > >> Water is always used with those bits for maximum life. However they > >> don't need a lot of water. Just enough to wash away the grindings. > >> With smaller bits (12-24") in diameter, the machines can achieve feed > >> rates of 4-5 inches per minute even when chewing through wire > >> reinforcement. Diamond tipped saw blade "teeth" are really tiny > >> diamonds in an alloy matrix which rubs against the material to be cut. > >> Its really more of a grinding process than a cutting process. A good > >> diamond tipped concrete core drill can drill through 100+ feet of > >> concrete before needing to be re-tipped if the core drill is treated > >> properly. > >> > >> I've never heard of diamond bits being used to solely cut cast iron. > >> I would think that Carbide or HSS would be preferable. > > Both would need large amounts of torque I don't have. My mill spindle is > > 1 HP, and not enough backgear to pull that off. So slow, dry, no sparks > > allowed, has now done the job with a $45 10 continuous edge Dewalt > > blade. And it seems to be taking less power to deepen its kerf now than > > when I started. Piece is now chucked in the lathe's 4 jaw, and I'm > > trying to make it round, but my backs stand up time has been exceeded > > for a couple hours. So I'm fielding email and may even see if I can get > > some afternoon nap in since I was up, in pain, about 1/2 the night last > > night. > > > > Cheers, Gene Heskett > > And you probably don't want to use a water hose to wet down the blade > even if it makes the blade last longer .. ;-) > > I've had good luck using 7 1/4" circular saw blades designed to cut > steel. They have come down in price quite a bit. I used them to cut > 1/2" and 3/4" plate steel. > I used it with a worm drive circular saw. The sparks were pretty > spectacular. I think that first blade I bought cost $60 or so probably > 15 years ago. I think they are about half that now. > They also work well cutting steel angle and bar if you don't have a > bandsaw. Just need to feed the blade into the steel carefully so it > doesn't grab and wear a face mask and gloves. > > Dave > > > ------------------------------------------------------------------------------ > Mobile security can be enabling, not merely restricting. Employees who > bring their own devices (BYOD) to work are irked by the imposition of MDM > restrictions. Mobile Device Manager Plus allows you to control only the > apps on BYO-devices by containerizing them, leaving personal data > untouched! > https://ad.doubleclick.net/ddm/clk/304595813;131938128;j > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Mobile security can be enabling, not merely restricting. Employees who bring their own devices (BYOD) to work are irked by the imposition of MDM restrictions. Mobile Device Manager Plus allows you to control only the apps on BYO-devices by containerizing them, leaving personal data untouched! https://ad.doubleclick.net/ddm/clk/304595813;131938128;j _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
