Funny . I was digging in the garden and found 8 all thread pieces with fasteners machined pretty much identical to what you're making . I remember making them but for the life of me can't remember what they were for . I have to stop burying stuff in the yard .I am going to make 9 adapters that are 7/8-14 on the outside and threaded .643/30 on the inside. I can do it all just need a tap made.