Wednesday, June 8, 2016

I've Got The Angles Down

No, wait... I spelled that wrong.  I've got the angles done.  As in two pieces of 2 1/2 inch angle aluminum that just get cut to length and then some holes drilled and tapped on both ends.  One end gets 8-32 and the other gets 10-32; they're both 3/4" deep.
My scrawled writing of "8" in broad tipped marker and "10" in fine tipped marker was to remind myself not to space out and drill the wrong-sized holes.  Yeah, BTDT a couple of times.

This, as you can see, was pretty simple work.  I cut the pieces to length a few weeks ago and was puzzling over the best way to hold them for the drilling, finally deciding to use the G0704 as a precise drill press.  I found that if I clamped one edge in my vise, and left the perpendicular edge just hanging there in space, that the angle wasn't close enough to 90 degrees to dial in a position to drill.  Over the 2 1/2", the angle diverged from 90 enough to put the far end (far from the vise) about .012" out of place.  So I was able to hold the pieces in the vise with the two edges on one jaw and the corner on the other jaw.   I marked them "old school": I colored the areas where I needed to work with the black marker, then scratched out the location of the hole centers.  Setup was a bit more manual, but no big deal.

The bigger, more important piece is the Y-axis extension.  This is a replacement for the one I wrote back in March; that one got obsoleted by my change over to ballscrews.  Which negates all my concern about the other one being made slightly wrong.  This time, instead of cutting a big hole which gets a diameter step (counterbore) using my ultra light duty CNC mill, I bored this one out on the G0704 itself.
There's somewhat of a jigsaw puzzle of how all this goes together, which I probably shouldn't get into too much, but this part goes on the end of the Y-axis, and those two, big, counterbored holes on the ends get hardware to press it onto the cast iron body of the mill.  A motor mount that I'll make next goes on top of this, compressing a set of bearings that get mounted in the big counterbore; the bearing mounting helps take out backlash.   I'm down to three pieces of aluminum to cut: two identical pieces (motor mounts) which are fairly simple and small, and the big X-axis end cap I wrote about back in April which will take some time to machine.  Then it will be time to take apart the mill, which obviously means I won't be able to do any more work with it.  So I'd like to be pretty sure everything is in good shape and working before then.

All of the parts in this post will be visible when the upgrade is done (unlike the ballnut mounts I did previously) so I think I'm going to paint them.


  1. Looking good. And using a blend of manual skills and CNC and electronic skills proves again that the more tools in your toolchest, the less likely you are to reach for the big hammer.

    Paint versus;
    Fabric dyes?
    Powder coat? (my wife has determined that using the kitchen oven to cure powder coatings will result is me having stress, still looking for used, inexpensive, toaster oven)
    Engine turnings? (depending on the size of the piece, the CNC mill could probably apply a beautiful pattern of engine turning)
    Electroplated finish? (I do not know if aluminum is a candidate for electroplating)

    Hmmm, move time to the future. CNC conversion completed and tested. Add in a dovetail router bit (end mill by another name). Might we see an old school wooden machinist tool chest, but the dovetails on the drawers, and the drawer slides would all be made by the CNC process on the big mill.

    Writing "the G0704" seems a tad cumbersome, but naming the G0704 "Millie" could be seen as tacky. (grin)

    Perhaps a naming contest?

    1. I got the inexpensive toaster oven and one of those low-end Sears powder coat guns around when I first started making things on the lathe and mill. '06 or '07. I've powder coated a few pieces, but not a lot. What's cool about that is you get much less overspray because the process is electrostatic. You clip a ground wire to the part you're painting, spray, and overspray is literally attracted to it. There's a kind of powder paint I use for painting fishing lures. No spray; just heat the lure, plunge it into the dry powder and swirl it around a few seconds. Still need the oven, though.

      I still spray outdoors, though. What overspray that gets away is a powder that can be swept up.

      One of these days, I want to take on anodizing, but that requires acid baths, and a lot of potentially messy things.

    2. After I finished the final twenty percent of machining on a project, I looked at the Calguns thread on anodizing. Lots of good information, but I don't have the comfort level to try it.
      That is where the suggestion on fabric dyeing is from.

  2. I've messed around with anodizing aluminum a bit.

    It can also be done purely by chemicals, not electricity involved.

    The Radio Amateur's Handbook had a section on painting/anodizing parts in some of the old issues, but I haven't seen anything yet.

    IIRC, you can anodize aluminum parts in a sodium hydroxide (lye) bath. After sitting in the lye bath for a while, you dunk the parts into a distilled water bath. If you want them colored, you can then dunk them into another bath containing "RIT" fabric dye, which will enter the pores of the aluminum oxide layer. Then you dunk the parts into boiling water for a while, which seals the pores, and the color.

    It sounds screwy, but it actually works.

    1. I've read quite a bit about anodizing at home and have gotten close to taking the plunge a few times. One thing struck me in that Wikihow article, though: "For best results, do this when the indoor temperature is between 70 and 72 degrees Fahrenheit (21 to 22 degrees Celsius)." I get a handful of days in a year that I can do that without running the air conditioner full tilt. This time of year, if I tried to do that during the day, the A/C couldn't get there. Plus, my electric bill would go over $500. Maybe $1000. I could probably get the temp in the house to stay at that if I ran it from midnight to dawn.