I have not used wood arrows in years, so im kind of shooting in the dark here. First, Id like to know how lose they are. You dont want a tight knock on a trad bow. A good way to test to see if they are truly too lose is; nock an arrow on the string, point the bow down, if it doesnt fall off you are probably ok. I like to loosen my knocks to where they will hold onto the string, just enough to where they will fall off when I tap the string, with the bow facing down. You can also tighten your knocks by heating them and bending them in a bit. Ive done it with boiling water. Just dip the knock in boiling water for a bit, pull it out, and press the two ends together. Mind you, this doesnt alway work with all materials, but ive had success with most all nocks made from simple polymers.