I've had my share of crashes too...don't give up!! I've gone through two complete main frame rebuilds, who knows how many skids and rotor blades, over 6 main shafts, two canopies, a tail motor and a battery brace and now I've installed an aftermarket radio system...but I'm still at it and I'm better than ever. The more repairing you do now, the more confident you'll be with your heli later and the more you'll understand it. When I first started out I was so paranoid that I wouldn't let the heli get above 3 feet off the ground. I couldn't hover and I could just skid. Now I understand my heli and we're good buddies, I let him (his name is Jasper
) hover about 2 feet from me, I walk circles around him, take walks in the park with him, and I even take him to school with me and fly in the mornings before class starts. Let's hope you're not as crazy as I am, but the point is that the more you respect and care for your heli, the better the experience you'll get.
Oh, and about the sheer pin, I'm using a very small, thin nail that fits perfectly. I guess this isn't the best idea though, but I've positioned the nail so that the tip of it is poking out less than a milimeter out of the hole on the other side of the plastic hub that fits over the shaft, so it's relatively easy to remove and there's a little give.
And the way I overdischarged my LiPo was from bench running the heli! I checked my voltage at 10.6 volts before I did some more motor work and revolution mixing (this was after I converted my radio system to my JR 6102) and suddenly the motor speed really started going down. I checkd the voltage and it read under 8 volts! Waited 15 minutes and it went back up to 8.99 volts by just letting it sit outside to cool down, but after that I've never trusted that LiPo and it hasn't worked as well. If I was flying with it I would have notice batt performance drop well before it went ctirical. So if you're benching your heli, be extra careful because you won't notice that performance drop soon enough before it's too late!
Anyways, good luck!