I have done a TON of research on this.
I talked to many users and suppliers. I.e T & S machines, regis, goodson, silver-seal and also several machinists.
T&S machines claims to have developed the dead pilot ball drive form tool system. Commonly called 3-D or regis now.(when he worked for peterson as an engineer) he was by far the most knowlegeable and informative of anyone.
He (T&S) reccomends the best set up for this (besides a dedicated machine) was using a bridgeport or other vertical mill . He said you also have to be willing to tilt the head on your mill (to reduce set up valve to valve on some heads)
He mounts a winnona air float table from a ph2000 on the bridgeport. adds a variable speed inverter drive, a 3 inch spacer to the bridgeport tower, ball drive tool kit, and levels
He quoted me $3000 for everything to convert the bridgeport.
He said the system used on other machines, IE seat and guide machines "gave everyone a taste and then they bought serdis"
But he definately thinks you can get very good results on a bridgeport or other full size vertical mill.
Most users of the systems on seat and guide machines I talked to can only achieve about .002" runout.
Recently someone here announced ball head tooling with lower guide suport being availible, but T&S didn't feel that or carbide pilots was a solution for sloppy machines.
Many hit the seat angle with a stone when they are done, but as T&S say's
"you have the seat just where you want it, then change it when you grind"
Hope this helps. I encourage you to talk to T & S machines in texas if you are considering this conversion.
He also reminded me they take visa and mastercard
