On Thu, 2008-06-12 at 03:45 -0400, W. Jacobs wrote: > I do not know much about CNC operation but need to ask a question about > the operation similar to this gear cutting. > > Machinery's handbook (20th) describes how to construct an involute on > page 288. I read this as the involute is the length of a line tangent > to the circle, equal to the cord of the circle part. > > Why do we not just calculate this in a spread sheet and plug it into G code?
This would be handy, but having a way to automated the g-code would be good. The more g-code way-points you can create the smoother the curves will be. But getting enough by hand would be difficult. > R = radius of gear > angle goes from 0 to 90 degrees > Angle /rad is angle in radians ... snip > 1.18 0.73 1177.92 729.55 > 90 1.57 0 0.75 1.18 > 1.18 0.75 1178.1 750 > > This seems so simple to me. I know that I need to adjust for cutter > size and also for root, pitch and outside diameter of the gear. And, I > have not run a formal analyze of my math. What am I missing? The more I learn about gears the more I don't know. It seems that some people have built careers on studying gear shapes. > I may have to turn the spread sheet into a text doc and then add the "x > mil" and "y mil" column's to a G0 column but that seems trivial to me. > As I say, What am I missing? Fortunately, I found that my CAD/CAM (Synergy) software has a gear utility that makes the creation of gear forms and tool paths fairly easy. > Thanks, My problem is I can't get the computer to wiggle the parallel > port. I'm working on it, and I will get it sometime. > bill Jacobs If you want to share your machine configuration and problem symptoms, someone here may be able to help. For the interested student, here are some links I have collected so far: http://en.wikipedia.org/wiki/Involute http://mathworld.wolfram.com/Involute.html http://www.metalwebnews.com/howto/gear/gear1.html http://www.engineersedge.com/gear_pitch_chart.htm http://www.roymech.co.uk/Useful_Tables/Drive/Gears.html http://en.wikipedia.org/wiki/Involute_gear http://en.wikipedia.org/wiki/Gear http://en.wikipedia.org/wiki/Image:Gear_words.png http://en.wikipedia.org/wiki/Leonhard_Euler http://www.smallparts.com/products/descriptions/gss.cfm http://www.csparks.com/watchmaking/WheelCutting.html OT: http://www.hobartwelders.com/weldtalk/showthread.php?t=30595 -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC/EMC CNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending Craftsman AA 109 restoration Shizuoka ST-N/EMC CNC) ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
