Friday, April 22, 2016

And It Looks Like This

Rather than prattle on about Earth Day, here's a picture of how that piece turned out.  I found a way to code the circle cutting routine in G-Code that created a semicircle.  I need to program in the start and end points of the arc (doesn't have to be a 180 degree arc), and the radius.  No need to go to the center or anything.  When I cut that, it was a 180 degree arc, and I cut off the longer "bat ears" on the left and right ends with a cutoff saw. 
It's a bit off center, but it seems to do what it's supposed to do. Here it is in place. 
There's a pair of 10-32 screws going through the ballnut (big piece with slanted edges) into the mounting piece in the front.  There's a bit of a question of what goes in those holes in the mount.  The drawings I'm working to say to put a pin in there that's 0.216 diameter.  The hole in ballnut, though, is .208, so that ain't happening.  I suppose I just turn it down to a smaller diameter, but I'm not sure. 

Remember, in honor of earth day, you should go burn some coal (hey, it comes from the earth, right?).  Better yet, burn some artisanal firewood.  Just be sure it's enough to be visible from Alpha Centauri.


  1. Looks good. Since you are going to fix it in place, the off center has no impact. And besides, you only off center cut it to compensate for the Coriolis Effect.

    But if we want the artisanal fire to be see from Alpha Centauri today, I think we would have had to light it 4.367 years ago.

    Another thought on the mounting plate. Does it have to have the angles on the smaller plate?

    1. You mean that big piece in the previous post?

      The triangle isn't important, the mounting holes are (the three around the central hole). It's most critical dimensions are that large hole - diameters, and depth of the counterbores. That hole holds a stack of ball bearings and shims that compress a desired amount to remove backlash from the end of the ballscrew. The triangular shape is where the stepper motor mount goes, and it's triangular instead of square because the new design tilts the stepper motor 45 degrees and replaces the turned standoffs I previously made with some 2 1/2" angle aluminum. The angle stock protects the stepper face and connection to the ballscrew from flying chips and coolant. Keeping it all square, like the original, and using a plastic shroud over the motor would work just as well.

  2. Nice job, workmanlike appearance. I like that.
    In honor of earth day, I dropped a couple trees for firewood.

    1. Thanks. I'm actually thinking about running them through a sanding/shining operation of some sort and then powder coating them. At least some of the parts, because they're eventually going to get splashed with coolant and metal chips. Probably get pretty rotten looking.

      Burn 'em bright!

  3. Whattaya mean, you can't put a .216 pin through a .208 hole? If you heat the hole and chill the pin, OF COURSE you can make it fit!

  4. Nice piece of work. And thanks for not bothering us with the Earth day prattle.