The Bobber stop is just a nail knot, if you crafty you will figure out a simple way to tie it. Here is my way to mass produce these little things.

I use a 1/4 piece of "teflon®" tubing about 6" long. In one end I drill a tiny hole using a 1/32 drill in the side of the tubing about 1/2 from the end. Like below

Now I take a 8"-10" piece of size 1 thread, I use a Surgical thread that is nonabsorbent manufactured by Gudebrod. I hold one end to the tubing and warp back on itself with the other end, 6-8 wraps is good. I then take the end I wrap up with and stick it through the hole and slide it out the end like so.

Then it's just pulling the knot up the tubing past the hole, which creates the knot. Below you can see the finished knot.

I like to make the knots onto larger tubing because it does not cramp the hands as bad. So then I push the knots onto smaller tubing where then I can cut them up for individual use. You can buy the smaller tubing at a fly fishing store and the larger teflon at the hardware store. I have even used the tubing for a stop bead between the knot an the bobber .