The car I'm rebuilding, an old Skoda Estelle with rear mounted engine, have transmissions axles that uses a key to secure the wheel hub. Its tip is conical, as the hub whole. The problem is that it uses only one key, and it eventually gets loose quite often, obviously damaging both the key and the hub.
My idea is to make new hubs but use multiple splines instead of a key. So it will be the same axles, fill the key slot by welding, lathe the conical section again and add splines to it, V splines like those in CV joints. My question is: adding splines would make the axle tip weak and more prone to break?