Wooden Mitre Box, or Stanley 150 Type Thing?

[Curt Putnam]

If you are still interested in the wood miter box, Lee Valley sells a guide kit that should help tighten things up - at least a little. After that, I'd look at a Nobex.

[Kevin Adams]

Hard to get a good shot of the spring. Here's a few pictures and hopefully it will give you an idea of what it should look like installed. The ends of the spring goes against the clamp and the middle goes against the arm.
Attachment 439493Attachment 439494Attachment 439495Attachment 439496

Thanks much, Chris. So the bend is on the outside, ie away from the saw plate vs towards it.

Take care,
Kevin