The Great Dane interchangeable topper I did I used M8 thread inserts similar to the ones CV3 posted, only diff being metho of insertion
I used Allen Key type.
I also used a collar as this added a lot more support to the joint, I adde the collar to the toppet, could have added it to the shank to save buying a collar for each topper ( Being a Yorkshireman) but thought when topper not attached it would be more pleasing with a collar, could then be housed in a decorative block using the protruding threaded bar and used on display .
The screw thread inserts were got from ebay and I believe they can be purchased in differing lengths
The one I used I fitted using a 10mm dia drilled hole-this was a tight fit screwing it in and didn't need glue, on reflection I would in future use 11.5 or 12 mm drill and bond in with epoxy to prevent any chance of the shank splitting on insertion.
Edited by Gloops, 13 February 2017 - 09:21 AM.