There are several sources for US made cutters. They all have in common their being horrendously expensive. I acquired a set of 16DP 14.5PA a while back from eBay. Actually acquired several sizes, some from China, some from Eastern Europe, some from Russia. I don't remember which source was for the 16DP set, they were all "second grade" stock that will work for plastic and aluminium. I did acquire several sets for small gears, but those were for model building. I don't expect to work iron or steel so saw no need for the high end cutters. Nor do I expect to do commercial grade or "job shop" work.
I did check several US sources, MSC, McMaster Carr, and a few others. They all stocked the cutters but were all beyond my means. I am not a "poor man", but I am unwilling to spend money where it is not needed. Making gears for my own use falls into that catagory.
As an aside on a related subject, I was interested that the general shape of a 14.5 degree gear is similar to ACME threads.(29 Deg) I experimented for a while using a 10TPI ACME tap to hob worm wheels. I still haven't got it right yet, but the problems I am seeing are from my fixturing, not the cutting.
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