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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
