Thread bump!. I have all my hubs off/ new rear disks to fit so am looking to do a stud conversion. My thought was to use countersunk bolts, wound in from the back of the hubs (countersunk slightly) then welded in 4 places to stop them backing out (unlike with Red Locktite). What grade are the original wheel bolts?. I have 15/20mm hubcentric spacers so will have to take that into account. I want something with a positive stop on the back of the hub / disk. I did a gearbox conversion and used same idea to secure flush backed studs so it should work.
Why not use threaded rod instead of countersink and weld on back still? Would save removing any material by drilling it.
Why weld it? I've got the studs fitted with locktite and they haven't come loose ever. The car is used on track only and has seen quite some wheel changes over the years. (At home only on street tires, on track on semi's, changes due to weather etc, wheels off and on before/after every trackday etc etc)