Where can I find 18 mm indexing washers?

[thefurnacedude]

Hello everyone. I was hoping that someone on this cite would know where I can find 18mm indexing washers. I have had no trouble finding the 14mm. Please let me know.

Tim

 

[MustangSix]

It might be easier to use 18-to-14mm adapters and use the 14mm index washers. That would also give you a better choice of plugs.