By which, she means our cat. But bored engineers are dangerous, too. I'm waiting, perhaps not sufficiently patiently, for the resin coat on the inside of the Sonotube to harden, before I suspend it by a rod through the interior, and do the exterior. In the meantime, my wife had fallen asleep on the couch, so I couldn't turn on the TV. What to do?
I had realized a couple of days back that there was some room to reduce weight on various accessories on the telescope. For example, the mounting bracket for the finderscope was something that I put together myself, but it was a flat piece of aluminum 3/8" thick. Lots of extra weight, and while it was not under any stress, a flat base against a round tube is less than optimal for stability.
So, I took that base and decided to mill it out to be a channel. The legs on either side would, like the rods in my previous example, provide a very stable base against the tube. (Yes, I should have used lower density acetal, either white to match the tube, or black to match the rest of the hardware on the tube, but I didn't have any pieces that were thin enough and long enough for this purpose.)
I don't use the vertical mill often enough to machine aluminum to remember: use a roughing mill for this. Instead, I somewhat botched the first attempt, and barely saved the piece from becoming scrap. You aren't going to see the bottom side of the channel -- it's functional but the milling marks and irregularities caused by my save are are way too apparent. In addition, because the plate is now much thinner than before, the 8-32 screws that mount this plate to the rings that hold the finderscope were now too long for the holes, so I had to deepen the holes in the rings and re-tap the holes with more threads. But I did knock two ounces off the weight!
Trying again:
ReplyDeleteWD-40 makes a great cutting fluid for aluminum, gives you a mirror finish.
I have never tried that before. Perhaps I am spoiled by machining acetal, which is self-lubricating. I will give this a try.
ReplyDeleteJust plain kerosene works pretty well, too. That was the cutting fluid of choice way back in the dark ages (when I worked summers in a machine shop.)
ReplyDeleteA bored engineer. . .
ReplyDeleteIs this perhaps how Bugatti autos came to be so @#$%^&* complicated compared to other luxury cars of their era?
;)