"One Perfect Part at a Time"

Sine of 45

I know most of my readers like action shots. Here are a few to keep the juices flowing. It’s just one very tiny step in the making of parts, but there is a bit of interesting machine set up going on here.

I had to cut a 3/32″ wide x 45 deg. chamfer on the one end of both of the two brackets I made for the tender steps. That doesn’t sound like much of a job, does it?

I priced 45 degree end mills and after I got back off the floor, I decided that wasn’t the least expensive way to run this job. At least for the two tiny cuts I needed to make. A file might work but it would look like… well you know, the smelly stuff.

I dusted off the sine vise and although it seemed like massive overkill, it wasn’t all that hard to set up. The fun part was I was able to do a little math and I actually like math. The reason it is called a sine vice is the height of the spacers (called sine blocks) is the sine of the angle desired times the distance away from the hinge.

Here I wanted 45 degrees, and the sine of 45 is sin(degrees(45)) = 0.70710678. I used o.707 as close enough. I have a 4 inch sine vice so the stack of blocks needs to be 0.707 x 4 = 2.828 inches. You can see that number on the top of the pink notepad in one picture. I rounded to 2.830 just to make it easier to build the stack and still be plenty (over) accurate for this task.

Two 1.000 inch, one .700 inch, and one .130 inch block does the job. The actual machining seemed trivial as it usually does. 🙂

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