Originally Posted by
spaceworm
I guess I need to ask what the diameter of the engine's prop shaft is? If it is 10mm, why is the safety nut 13mm? Could your safety nut be I/2 of the locking prop nut used on Saito engines. My engines have a special nut that tightens against the prop washer. Then a special tapered split cone type nut is tightened against the first nut. The split taper and nut act as a collet to lock the nuts together. But, I could be way off base here, 13mm is not a standard prop reamer size. A final step to 12mm (0.472 inch) is available from several sources. 13mm is 0.511inches. Maybe a 1/2 inch (0.500 inch) would work, but then you need a reamer with a 10mm pilot with a 0.500 inch final step. Not likely to be found. If you really need to ream to 13mm from a 10mm pilot hole, then a 13mm end mill with a 10mm pilot is probably available from a machine shop tool supply. This is not likely to be a hand tool but to be used in a drill press or milling machine. Good luck.
Sincerely, Richard
AMA 861960
Club Saito #635; Saito 56, 100, 120abc, 130T, 180
edit: add prop nut image: Is this the prop nut you are using?
Spaceworm, Blw and Fnqflyer
Thanks, the engine is not a Saito but a Laser 300v. Hence my remark that this may not be Saito related but more on how to enlarge a prop hole if you do not have access to good quality drill press.
The "safety nut" is actually a 13mm sleeve nut on 10mm cranckshaft. The sleeve nut is secured by a 10mm bolt that is center drilled and tapped to accept a Tru-Turn spinner bolt.
A friend of mine had a very nice tapered reamer that he used to help me to enlarge the APC prop. I tried to figure out what make it was buy there was no name on it. It seemed to have at least 8 cutting edges that were very sharp.
We then tried the same tool on a Menz-S 20X6 prop but the grain of pine material did interfere a bit. I hope I got the thing done "good enough". At least both props feel very tight when I slide the sleeve nut into the prop hole. I will anyways balance the wooden prop although I'm a bit unsure if the balancing can be doen properly if the reamer has wandered a bit on prop surface.
Btw Spaceworm: The safety nut in the emage is the same I use on my Saito FA-125a with great success!