One of the biggest complaint's I've heard about the Tsprof knife sharpener's is the little ball they use on the handle and how small it is and uncomfortable it get's after a while into a long sharpening session. I just ordered a few thing's from ebay that I'm waiting on to show up I can not provide links because this site will delete links to websites that sell stuff and does not support this site but I will include picture's and the sellers name. Try using this in the search bar at ebay to find the threaded insert's,M6 M8 Furniture Unhead Nut In/Out Threaded For Wood Insert Grade 4.8 You need to order threaded insert's from a seller called superiorsell2014 and you need to order M8 threaded insert's from him and ask him to send them by epacket I find it's a much faster method of shipping. The you just need to find a wooden ball around 1 1/4 and 1 1/2 and drill a 10mm hole the same length as the insert into the wooden ball and screw the insert in,I don't think these insert's come with any kind of slot of hex to drive them you just need to use a M8x1.25 bolt as the drive. I ordered the 15mm threaded insert's and in Canada I was able to get wooden balls from Lee Valley Tools,you can use a bit of epoxy or crazy glue on the outside of the threaded insert to hold it in place. I will post picture's of my stuff when I get it in and put together,also epacket shipping to Canada for me is between 7 and 13 days most times and doesn't cost more.