Inserted threading boring bars

Just looking for recommendation as to which of these actually work well, I've not been having great experiences with our solid carbide from sct, not more then 20 threads in mild steel before it dulls, plus I wouldn't mind coolant through.

I'm talking just normal us/metric threads, no Acme or anything unusual.

But here's the catch, I want one that I can fit into a 3/8 hole without issue, heh seems like a long shot after going through catalogs.

Thanks, John.