Ive seen several different ways, you can use your chainsaw file that you used on your string knocks. I've seen a couple hacksaw blades tape together used. As well as a dremel tool and a band saw. I use a ceramic tile blade in my hack saw for the inital cut followed by my chainsaw file. All you have to do is get a notch cut in the end.
I've also seen where people make the "Clip on" arrow nock. Mark the bottom of you nock, drill an 1/8 th inch hole through the side. Then cut the top of the nock a bit smaller than the hole so that the arrow clips on the string. If done correctly it works good. But I've also seen these crack with some use. I guess its from spreading open the end as it clips on the string.
Hope this helps.
Patrick
