I just picked up 2 bobber lights at Bass Pro. Went home pulled them out the package. Did exactly as shown in the youtube video except drill all the way through the nock-I've had solid nocks split, I don't think weakening the nock at the point where it needs strength as being the best idea. Anyway, super glued put a cut nock on the light battery to act as a stop to engage the push/pull switch and then the SOB wouldn't light consistently. I screwed with it for a 1/2 hour and it only got worse. I spent almost $5 per light and then spent 45 mins trying to make my own.... the outcome= I will buy 2 tracer nocks for $10 more and feel confident they will perform the way they should. the idea of making your own is neat though I will say that, just not worth it to me for something even at best has a 7 hour battery and does not blink like the tracer.