First CA the snot out of the holes in your prop second but a dab of Blue locktite on the prop bolts if it is a new prop check the bolts tightness after the first couple of flights and retighten as needed, problem solved , the problem is that your props wood is compressing thus the bolts loosen, follow these very simple instructions and once the set up is broken in your problems will be over until you perhaps break the prop then it begins again , harden the prop holes with ca and then retighten the bolts after the first couple of flights and it will stop and become very much dependable, there is no need to convert to a single prop bolt when you tighten a metal mechanical fitting against a soft wood surface it will compress against the load unless it is hardened with CA to stop the woods compression against that load, if you harden the prop holes it will only compress to a certain point then stop just like how a motorcycle chain will stretch under load to working tolerance and then stop. just my .02 but it works 3 plus years on the same prop and no failures to date ya gotta look at it as if what kind of scrutiny would I give it if my ass was sitting in it.