[Station X]

Turn or file some metal discs to the correct diameter. Alternatively you may be able to find coins or washers of the correct size.

Clamp paxolin betwen the discs and file to the correct size.

Achieving alignment of the discs might be a problem. You could try glung then to the "jaws" of a 'G' clamp. The paxolin might be transparent enough to see through with a bright light behind it, then you'll be able to see both discs to align them.

Have a go with a couple of washers or coins first to see if the idea works for you.