I have made up many fittings from the parts casting tree , it is tedious & difficult & sometimes I still ruin one , very difficult to get them 100% (true) ,but it is a lot cheaper than buying already made up , & sometimes I use un-threaded fittings & soldered together. A vertical mill is a must imho.
I have access to several vertical milling machines and lathes....my primary reason for ordering the kit version is so I am not locked in to a particular steam pipe size or brand....I have learned many Wilesco engines run 3.5mm steam tube...2.5mm Internal diameter. I believe Wilesco steam pipe is mostly nickel plated brass and sometimes polished brass. My favorite color metal is Copper...the size used is common refrigeration size in copper. I can purchase in 10ft lengths for $10
Most Wilesco pre bent steam pipes are $30-$50 for 1 pipe. I can make that pipe for $1 material so I have $29 left to spend on pretty steam fittings....I never lack for argument to spend $ on toys