I am attempting to restore a 1935 Marshall and Wendell and have some trouble tracking down the right size agraffe replacements. They seem to be larger than the standard 1/4 inch size.. Measuring approx 9/32 or 7mm with the same thread pattern as the 1/4 inch standards. I have sent emails to various vendors and the usual response is they have never heard of that size before. Has anyone else come across this before or heard of this size agraffe?