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. Dave On 5/9/2016 11:13 PM, Gene Heskett wrote: > On Monday 09 May 2016 22:40:45 andy pugh wrote: > >> I am not an expert in diamond sawing, so take that as a caveat. >> However, as far as I know diamond turning of iron-based materials is >> almost never done. For iron-based materials the abrasive of choice is >> CBN. >> The reason for this is, as I understand it, is because carbon is >> soluble in iron. In fact the whole marvellous thing that is ferrous >> metallurgy is just playing games with the various things that >> solutions of carbon dissolved in iron can do when you heat and cool >> them. >> >> Diamond turning of aluminium and copper alloy parts has been standard >> for 50 years or more. You won't find many references to >> diamond-turning of iron alloys. > Thanks Andy. I should point out that I am not turning it just yet, but > sawing off a slice, nominally 1.75" thick, that I can turn, eventually > into a block the same height as the compound carriage is, to add some > mass to the crossfeed, and to offset the QC holder to the rear and > right, thereby putting the typical cutting tool much closer to the > center of the Z carriage so the cutting forces are essentially straight > down on the center of the Z carriage. And that I am not achieving a > temperature where the carbon (in the diamond dust) can dissolve into the > iron. At no time has the blade or the workpiece been heated to the > point I can't rest my hand on either. Slow, but it seems to be a pretty > precise way to do it, so far. Got a huge pile of grey cast iron dust > though. > > Ignore that thumping sound, thats just me, knocking on wood. ;-) > > Cheers, Gene Heskett ------------------------------------------------------------------------------ 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
