I am going to attempt to make a prop hub for this Mculloch weedeater engine. I am not sure of the cc's but this engine is smaller than a 25cc so I am guessing that it is around 18 to 21 cc. I know that the shaft is 5/16 but I am not sure if the threads are 24 or 28. Does anyone know offhand? Thanks. I know I could just order a prop hub from Dave Carr or Ralph C. , but I have a neighbor that has a huge lathe and I would like to give it a try. He has tons of bar stock laying around.