To prevent me going bankrupt I had to buy seized ones on eBay and rebuild them with new bearings and seals. But mine are an oddball size - VDI40 Beaver ones with a drive end that is the REVERSE of a Baruffaldi one and slightly shorter.
I ended up 3D printing a new drive dog for the lathe to take standard Baruffaldi ones and had it lost wax cast in bronze, then rebuilt the three seized ones
As an aside, an ABS printed drive dog worked fine for lightish milling in the lathe before the bronze one arrived !