I’ve finally finished machining the slots in the end of the knurling tool arms. It’s been a slow process as each pass of the milling cutter only took of 0.5mm and I had to machine both sides of the slots giving 8 operations in total. It took me a few attempts to shim the metal to the right height so the first couple of slots required some additional filing to fit them to the knurling wheels and body of the tool.
The next steps will be to drill and machine the slot for the threaded bar and to machine a half round out of each side of the arms. However I would like to do some calculations as to the correct location of these before I start cutting metal.