Tue Jul 21 2020

Center arm rest lid

Doing some lathe work today. This is a start on the button for the latch. It'll be attached with a single rivet, so I'm getting ready to countersink it here.

The finished button. Why are the sides conical? Since the lid is quite shallow (about 7/8" high), and the latch is of a pivoting sort (see yesterday's update), when I press the button (not shown in yesterday's update, but it will just stick through the side of the lid), it will swing in an arc. Without conical sides to the button, the hole in the side of the lid would have to be quite large (i.e. ugly). However, this way, if I make the button conical and the hole in the lid conical, the conical surface will be a close match to the arc it follows. That should be about clear as mud. Don't worry, it'll make much more sense in a few days.

A U2 flew over while I was working in my garage shop.

After finishing the button, I got started on a little custom tapered reamer in order to ream the button hole in the side of the lid. Since it's going to be reamed from the inside of the lid outward, it needs to mount in my right angle drill, so a 1/4-28 thread is in order. In the past, when I've tried to use a die for cutting threads, I've had problems with cutting them at an angle rather than coaxial with the part. So, I decided to try threading on the lathe. Having never done this before, the result was predictably crap. In my own defense, there were a number of things going against me:

  1. The only way I have to grind cutting tools at this time is by hand on my bench grinder
  2. The only way I have to set angles on the lathe cross slide is by holding a protractor up
  3. I'm cutting steel, which is a bit of a challenge for this light-duty hobby lathe

I did manage to get the threads started on the lathe, so I thought that I might be able to pickup on those threads and finish them up with a threading die. I used the spindle to hold the die down to the work surface in an attempt to keep the die squared up.

Snatching victory from the jaws of defeat? Maybe...I'm sure I can scrap this part in another operation tomorrow, but for now at least the threads are OK.