Here at the LCM+L Skunkworks, some of the folks have been working on a Little Punched Card reader, so Visitors can see what they punched in their punched cards. Jeff and Hunter have been working on the electronics, while I have been building mechanical parts for them. Here is a picture of where it is today:
You can see it is made from clear plastic, so you can see EVERYTHING. This being a prototype, it has a few warts: like those extra holes in the sides. I had never actually used the boring head with my milling machine, so I had to figure out how to use it. Boring heads are used to make round holes, usually larger than you can get with drills. Yesterday, I made some new side plates, sans extra holes.
I started by drilling the holes for the 6-32 screws that hold the thing together:
Once I had the holes in, I had to put in the bearing holes, this is where the boring head comes in. I have drills up to 0.500″, and a 0.750″ one, but the bearings are 16mm in diameter, or about 0.630″. I start to drilling the bearing holes to half inch:
Then I have to bore out the holes to 0.630″ with the boring head:
The gray part moves to adjust the size of the hole, here is a picture of the business end, where I can adjust the size of the hole it makes by 0.001″:
After I added the holes to hold the motor mount, and a bunch of filing edges, here are the two sides, sitting on Jeff’s desk:
I mentioned that I was doing this on my milling machine. If you don’t know about milling machines, they are basically like a very rigid drill press, with a movable table to hold the part you are working on. I can move the table around very precisely to get the holes Exactly where I want them. You can also work on the sides of the parts with special cutters, which is how I got the plates to the basic shape. Here is a link to what my milling machine started out life as: http://www.grizzly.com/products/Mill-Drill/G0463. It was smallest machine that I felt could be called a real milling machine.