Well, three arc minutes is a 20th of a degree. There are 20 * 360 = 7200 of them in a circle. A circle with a diameter of 10 inches has a circumference of 10 * pi or 31.4 inches. Divide that by 7200 -> .004.
So, you can probably answer the question. Imagine a flat piece of ground steel 10 inches square by 1/2 inch thick. Indicate it in to be perfectly horizontal. Then flip if over to the other side. Now run your indicator over that piece of steel. Is four thousandths too large an error? (The edge to edge difference will be twice that.) I think the answer is that is not precise enough, but your answer will depend on your application. Ken On Sun, Nov 4, 2018 at 3:57 PM jeremy youngs <[email protected]> wrote: > Hello all ,I just purchased several hd brand gear heads . I have a question > about the backlash call out of 3 arc minutes. One of these is fairly large > and I would like to use it as an engine block rollover . I have a 10*50 > comet and I want to attach my van Norman boring bar to it . This will > eliminate having to lift that 250 lbs and allow measurement of bore without > disturbing the bar. > My question is , is 3arc minutes too much for this process ? And could > backlash be effectively reduced by putting a brake at the opposite end of > the rollover fixture and preloadi g the gear head ? Obviously attention to > that detail would be required. Thanks fellas > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
