Here's a quick and dirty write up of what I was going to do. The reason I say was is because the circumference of the worktable on the drill press was a bit larger than I had anticipated for doing this. Hopefully by showing the method of approach you'll understand why.
I first got a piece of paper about the width of the rim of the table. Wrapped it around so the paper folded over itself.
Then using a square I made sure I cut a square corner on the paper.
Now the careful layout begins. I'm only going to use a portion of the paper to demonstrate the process. Draw two lines perpendicular to the strip of paper, both are end lines. Using a metric ruler I divide the horizontal line (paper) into 8 divisions. I used 320 at the left end and 0 at the right end. If you divide 8 into 320 you get 40. So every 40 centimeters I made a mark for a vertical line.
This is what you'll wind up with.
Next fasten the paper to your table.
Then make up a pointer such as shown to line up the lines on your paper. Now you can drill your holes.
I have not gone into great detail on this method as it would take a large amount of time to explain. Hopefully those with some insight can figure out what is being done.
The reason this wouldn't work for me is the fact that my drill table is over 42" in circumference. Trying to divide a piece of paper that long called for one long angle to come up with a number divisible by 24.
So it looks like I will be using the DRO on the Bridgeport after all.
Perhaps someday I will give this method a try on a smaller part,
For those who would like to read further on this method you will need either the old copies of "The Home Shop Machinist" Nov/Dec 1988 where he wrote the series on a Model Makers Dividing Head or his Shop Wisdom of Philip Duclos. He gives a full description of how it's done.
If there are any questions I'll try to answer them as best I can.
One other method of originating an index plate is written up in Guy Lautard's Second Bedside Reader. You will need a lathe for that project.
Bernd
