chainplates: round holes vs square holes

[billknny]

Some of the chainplates on my boat are mounted with what are essentailly flat head machine screws in a countersink. What makes them unusual is that the head has an undercut on the taper, making for a very large head, looks good, has held up without a prolem for 30 years.

You can have great fun flipping through a McMaster-Carr catalog for just the right bolt to meet your needs...