Yes, super easy to thread the bobbins. With the kit comes a piece you place onto a drill. You place your thread spool on a pencil (I'm not sure what I used), and press the button and watch how fast the thread moves onto the bobbins. It takes about 2 minutes.
If you do purchase the entire set, I would recommend picking up an extra bobbin. I have 3 right now, and they are IMHO the best thing to happen to fly tying.
Wish I could say more about this fine product. It sure is a pleasure to use. I thought for sure that I wouldn't be able to tie such small flies with it being that the jaws don't really like like they could handle a midge type pattern, but believe me, they work great.