here's a tip I found works better then a square knot on my tied nocks. I also use the over hand knot method rotating side to side and I work my way UP away from the arrow to keep the arrow off my final knot. Nothing else is different till the end knot which is as follows.
Do a double or triple overhand at the end instead of the square and pull tight. (by this I mean instead of going through once on an overhand,go back around again a time or two, you can practice this on your shoes if you dont get it you'll see what I mean, it holds TIGHT!)
I'm using regular ole number 4 nylon for my tied on nocks. Now cut your tags oh 1/8 or so. I like to leave mine just about the length of the nock itself, no longer but no shorter then 1/8" +-. You'll see why when you try it.
Now burn the ends and get them melting which doesnt take much. Instead or leaving them as stubbs, wet your finger to keep from burning them and stroke them to the side of the nock while the tags are melting (BUT NOT BURNING!). You need to do it fairly quickly but it works like a champ. I do add a drop of duco very lightly to the outside but have omitted this step a time or three and havent seen any difference as to the things unraveling or otherwise. I do believe this drop of duco lightly applied helps keep the nock from fraying as number 4 nylon, though durable with start to frizzle a bit with a lot of shooting. You can burn this frizzle off or just coat it very very lightly and it wont happen! If they don't stick well to the nock, a little heat will soften things up enough that you can lay things down flat as long as you didnt get your fingers too wet. If you did you may have to retie a new nock and start over or cut your nock a little shorter by unraveling one overhand not and refinishing. Again it doesnt take much if you fray the tag ends first. They'll conform to the nock when you lay them down so it's a very thin layer with no sharp edges
And, prestola, the perfect nock. No lumps, no bumps, no tag ends or sharp edges to cut ya, nothing! Just a nice round smooth nock. Much better then dental floss, which I also used for a lot of years. It'll last as long as the string lasts with a ton of shooting!!!!
The dental floss is nice, and fairly permanent but mine would always start to fray overtime and you cannot adjust it like you can a tied on nock up or down the string. Meaning once it's on, it's on that spot for good atleast for me! What bothered me the most was the nock desintagrating with a lot of shooting regarldess of how much glue I applied to it though I never did try epoxy. I used to shoot daily year round. My strings, servings, and nocks (before anything other then b50 was used), would be destroyed in a summer of shooting. That is the main reason I learned to build my own strings early on. THey were pretty crude, but they worked. If ya ever saw a peddle biker, with a recurve on the front handle bars, riding down the sides of the road from phalen lake north to forest lake in Minnesota backquiver on, and a bike loaded down with stuff, that was me way back when LOL! What a site that must have been.
Just a note, I have not tried this method for tying on a nock with anything other then number 4 nylon serving material. I use this over a spectra serving and have a ton of it here so I have no plans on trying any of the new hybrid servings for a nocking point anytime soon.