GiantScale

I needa M4 prop screw instead of the M3 screw for my project. Does the norvel .061 R/C crank have enough material for me to drill and retap the prop screw larger to M4?

Would the crank still be strong enough to withstand high rpm abuse?

Thanks

Toad

I was contemplating doing the 4mm screw myself, after measuring, there is not enough material left past the thread depth to be safe, and this is if you could tap the hardened crank in the first place, the crank is incredibly hard. a carbide tap would be needed and I bet you would break that in the effort. I would not even attempt it.

GiantScale

Thanks for the heads up Toad. I was afraid of that. Chucking up the crank in a lathe could damage the bearing surface also.

My problem lies with the M3 shouldered screws I can buy. They all have .118 (3MM) shoulders. I need a .125 shoulder to mount a octura .125 x .098 flexhex just like the screw that is supplied, but longer. I tried to thread a .125 steel rod only to wear out the die and break the .125 rod in less than 2" of work. I think I needed to turn the threaded area down to .118 before threading, but I dont see that happening with such small material.

Any Ideas anyone?