I was a little concerned that 20 teeth (80 quadrature) wouldn't be enough resolution. After cutting a couple of 0-80 and 00-90 screws on both the machines and testing with commercial nuts and examining the thread geometry under the microscope I no longer have any reservations about 80 quadrature not being good enough. If I can consistently cut 90 tpi in multiple passes and leave a thread that is perfect in form and pitch then I think it will do fine for the typical 40 tpi to 8 tpi that one normally is required to cut.
By the way the threads are cut in about 20 passes so the resolution and repeatability have been thoroughly tested. If you wonder why it takes so many passes you have probably never actually held a 00-90 screw in your hand. The diameter is .043 so the radius is .0215. How deep a cut do you think you can take on that little sucker even with a tool that's as sharp as it is humanly possible to make it. I know when the tool is dull because it just pushes the little fellow away and breaks it off as it climbs up on the tool. I am sure I could cut a 000-120 thread but I don't have a nut to test it with. If on the other hand I was using the spindle as a servo driven axis I would probably want more slots. By the way I am thinking seriously about repurposing my HF 7 x 10 lathe as a CNC tool and cutter grinder for the single lip engraving tools I use which are in the neighborhood of 20 degree included angle with a tip of 4 to 15 thousandths. I previously had it set up as a cnc lathe with a very large brushed servo driving the spindle and controlled as the A axis. It worked well enough but the top speed was limited by LCNC's ability to produce steps fast enough to use the motors top speed. The encoder on the servo was 500 lines so the resolution was far better than I ever needed and it would work happily at ridiculously slow speeds e.g. 1 to 10 RPM as would be used for a the work holder for a cutter grinder. With a grinding wheel on the cross slide I could produce the tool tip geometry and relief just like the big boys. I robbed the x and z servos from it to install on the Jet 9 x 20 and used the spindle servo as the z axis servo on the 10EE. I guess I'll have to go servo hunting again. Cecil ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
