I concur Paul. I have been using Precise Parts for custom adapters, collars etc for years now. Some of the parts I have had made have not been straight forward at all. Although I have some machining skills, making fine threads has never been my strong point for example. I'd estimate I have had well over 50 items made by them and all were to spec and service has been first rate.
There are plenty of great engineering shops out there that can do the same thing or much more and likely for less cost but I think Precise Parts have the edge because of their understanding of the needs of this crazy hobby (?) we have

. Other people no doubt have had similar experiences with other service providers out there.
g