Having a problem on one of my bows,the arrownocks are loose.Tried wraping dentalfloss works for a while but doesn,t hold up.What do you do for the problem???

Try sticking the nocks in very hot water (not boiling though) for a second or too and see if you can't mold them to the bow string.

I have never had trouble with dental floss  

Put a bit of water in a coffee cup deep enough to cover 1/8" or so past the throat of the nock. Put it into the microwave long enough to get it boiling, usually sixty to ninety seconds. Remove and put your nock into the hot water for 3 seconds then pinch it down at the throat between your thumb/index finger then put the arrow on your braced string a couple of times. I have done 6 arrows then brought the water back to a boil to finish a dozen.

Did you put super glue on the floss after you got the proper fit?  If not, try that.  Other than that, serve the strings to fit properly.

Waxed dental floss with a little heat to bind it together.

Why not reserve the string with a heavier serving.

I have found that 15# artificial sinew makes a fine nock serving. It's waxed and flat. Serve about 3/8" area below the nocking point. I like it better than dental floss.

put a few strands under the serving. and serve as normal.  Dick

I also go under the serving. Floss always failed after time

Dental floss dont last long time,I use braided fishing line" power pro brand " in 30 lbs.
I have this on my bow for at least one year long now and nothing move.
Dont forget tu glue it with super glue to.

Dental floss holds up for me.
I may tie it on differently though.

I do the "overhand knot, flip, overhand knot, flip..etc."
Finish off with a square not.

This method does add more diameter than just wrapping it around of course.

So it may or may not give you the right fit.

I dont have any string making stuff yet but reserved the area with a dacron strand from an old string i had around. Works great.
I tried dental floss but it must not have been tight enough and onlylasted 100 shots or so

I switched my nocks to Bjorn Snap on and never looked back.

Trying to reshape a bunch of nocks to be all alike is a lot of work and difficult to do right in my experience.  Reserving the string is quick, simple and consistant.  Takes less than 5 minutes once you get the hang of it.

Tend to agree with reserving the string. If I have to adjust nocks, I'd rather have them too tight.

DITO, WHAT SWAMP YANKEE said

For safety reasons I'd avoid the boiling water approach...a dry fire (broken nock) may eventually happen and those aren't fun.  As others suggested, a better long-term fix is to re-serve the string with a larger diameter serving material.

Piratkey I do the same thing. Braided fishing line. Never starts fraying out. rat'

Dental floss does it for me and it lasts long