A friend gave me a bag of billiard balls. I figured I’d make some coat racks out of them. However, holding them to drill holes for dowels was a challenge.
A quick check around the Net returned several good solutions. However, though several of the methods kept the ball from moving around on the drill table base, they didn't stop the ball from revolving, even if it couldn't move around the table.
Initially, I had elaborate designs in mind ,for the means of holding the balls, but items already setting on the drill press, from test holes, presented a quicker solution.
To make a simple sphere drilling jig, you'll need the following:
1) A drill bit the size of the hole you want to drill. A Forstner or spur bit will work fine for things like the billiard balls. So too would a spur bit, I suspect, as long as it's sharp.
2) A hand drill or a drill press. The drill press is the preferable tool, since holding a hand drill straight and making a, for example, 1/2" diameter hole will be a challenge.
3) A wood clamp, like the Jorgenson clamp in the photos.
If you don't have one and want to make one, consider my simple parts holding clamp making ible at https://www.instructables.com/id/SMALL-PARTS-HOLD...
You may also be able to use a small (e.g., 6") bar clamp. You'll just have to experiment.
1) An item to drill and which lends itself to such processes (had to mention that to keep things official).
2) A scrap piece of wood you can drill a hole in or which already has a hold drilled in it and the hole which is a little less in diameter than the item you are drilling.
Step 1: Drilling Balls
The piece of scrap plywood I use under material, when drilling, and for drilling test holes had a hole big enough for the ball to sit in. This gave me the stability I needed.
The size of the hole is not critical. Something in the ballpark of a 1-1/2" diameter hole will work fine.
You can use a spade bit, a hole saw, a Forster or a spur bit to get the job done. Of course, don't forget to place something under the material to protect the bit from the table, and to protect your table.
Now you need is another piece of scrap the same dimension as the one you just drilled. You will lay the clamp on it, which seems to make it a bit easier to accomplish the task of securing the pool ball.
Anything big (wide and long) enough to support the clamp will do. Too, because of how you are using the support pieces, it should not be damaged and can be used for this again, or another project.
Now, keeping them parallel to each other, open the clamp so the jaws are open just enough to drop a ball between them, then lay the clamp on your support with the open end just over the hold. Drop the ball into the hole and tight the clamp.
Using a bit appropriate to give you a snug fit for a dowel in it, or to produce the tapped hole you need for your 26 roadster shifter knob, drill away.
For larger holes, such as dowels for coat racks, I like Forstner bits and spur bits. They give clean holes and cut well.
The attached photo shows a few balls with dowels inserted and installed in a, as of yet, partially finished coat rack.