I bought a USB charging jack designed for a car's dashboard, and
designed to fit in the same size hole as a cigarette lighter.

Many versions for sale. This one, no more expensive than the others,
came with a hole saw for 1 1/16", a size I don't have**. The hole saw
has the shank, the center drill bit, an allen wrench, the hole saw
itself, and a spring!!!

A tapered coil spring whose small diameter just fits the bit. Is that a
coincidence? What is the point of the spring? I've used a hole saw
before and didnt' feel a need for a spring. Is it to force out the hole
after it's been cut? Have you seen this before?




**Last time, I think I used a 1" hole saw and a reamer to make the hole
bigger. Now I can't find my reamer and NO ONE sells a reamer that big.
How can that be? I don't remember where I bougth the one I have, but I
think it was a yard sale or hamfest, not retail. It's metal with a
yellowish top and an unevenly applied vinyl overlay for the top. Where
can I get another one?