Citizenschallenge.pm Post #4
I really wanted to take it home. The setup was in a big wooden box. I know its wrong, but I did think about it. I would have had pictures, but this was before we had cell phones like today. It was before I even had a cell phone, but like other classified project, cameras and cell phones are not allowed in the buildings.
Today we just broach square holes.
This method required tooling setup. You’d have to be a better machinist than me to do it on a drill press. So a mill would have been required.
1. Step one would be to attach the drill block.
2. Place the round drill bushing attachment for round hole.
3. Insert the proper drill bushing for your bit size.
4. Do steps 2 & 3 until you got the size of hole needed.
5. Remove round drill bushing attachment.
6. Place drill bushing attachment for square hole. This attachment turned in a off center movement.
7. Insert the size of drill bushing for the special square hole drill bit.
8. Note; this was a one flute bit.
9. Turn slowly with small bite.
The basic method.
The box contained about fifty round and fifty square drill bushing sizes, one drill block, two drill block bushing inserts (one round, one square), fifty one flute drill bits. It did not contain any round drill bits.
Note; the square drill bushing inserts turned off center and on roller bearings.
TromboneAndrew Post #5
At the time I was General Dynamics Air Force Plant #19 as a Jig & Fixture Builder. They had no machine shop there. I was trying to figure out a reason to have them send me to the machine shop at the main plant so I could try it out, didn’t happen.
My guess is that the hole would have been ruff and any good machinist would have cleaned up the hole with a file.
But yes, it would have been a square hole with square corners. I came to that conclusion by turning the off center square bushing attachment. It seemed to have a cam like movement, but without dissembling the unit I’m not sure. I forget to add the drill chuck to the list in the box, the chuck turned off center and the drill bushing attachment moved with the chuck. So you would put the Chuck in the mill after you drilled the round holes.