They do make hand taps that can be used to cut threads into various materials to adapt to a spindle thread. I have turned a number of aluminum and a few steel face plates and hand tapped the threads into the piece. Standard practice is to mount the face plate after cutting the threads and true up the face of the plate so it is perfectly square to spindle shaft. Cutting larger threads by hand takes a little patience and a few additional tools to hold the work piece and the use of additional hand wrenches to turn the tap or billet while keeping the tap centered on the work piece. This can be done by mounting the work piece on a lathe chuck and keeping the tap centered on a tail stock while advancing the tap into the work piece. Anyone that owns a lathe should also own a tap the same size as the spindle thread this allows you to fabricate various accessories for your lathe when they are hard to come by. A tap will pay for itself many times over by making your own Jamb Chucks, Longworth Chucks, Face Plates, Pen Mandrels, Mill Mandrels, Stopper Mandrels etc. The time it takes most people to research and shop for that new lathe accessory or tool I can usually have one built and in use on my lathe the same day.