Going crazy here...trying to widen the nocks on my carbons. Tried giving them a dip in boiling water (from 6 seconds to up to 20 seconds) and then fitting them at the narrowest part of the groove, to the string. Nothing...doesn't seem to be the slightest change. Any suggestions???

I find it better to file or sand them to fit for the nocks that fit alitle tight.But the nocks I use in 5/16" carbons and uni-bushings is Easton 3D Super nocks,they fit great on 12 strand D97 with .024 Halo without doing anything to them.

IMO, plastic nocks are pretty thin to start with.  I don't like to sand or file them.  What about removing the serving and reserving with thinner thread?

Try the boiling water thing again (I count to 10 one thousand) and then rather than putting the nock on your string, jam in a nail or something about the same size as your string and leave it there for 5-10 seconds.

I usually do that to all of my arrows (just did a bunch tonight) and then when I'm done I go back and check each one on my string.  If one is still too tight, I do it again.  If it's too loose, then 3-4 seconds back in the boiling water and I pinch the ends of the nock a bit with my fingers.   I think it took me about 10-15 minutes to do two dozen arrows (give or take) and they all fit juuuuust right now.

I'll go along with the GingivitisKhan. Nocks are made of thermo plastic, so it should work.

I usually opt to shave mine out with a sharp utility knife, but it's easy to take one-swipe-too-many and end up with a loose-fitting nock so you have to take it slow!  It thins them out a little, but I use Bohnings and have never broken one during the shot (some odd-brand unmodified florescent orange nocks I HAVE had break - not cool!)
Your lack of success with boiling might be due to the nocks themselves - maybe it's a different brand and type than others have worked with?  I would imagine that the type of plastic would make a difference...  maybe others can throw in their 2 cents on that aspect.

Im with Orion on this. Why spend a bunch of time messing with nocks when you can weaken them and risk breaking one on a shot.

I serve my strings to fit the nocks.

3rivers sells inserts that lets you glue on any nock that you like.    Nock adapters

The description states that these adapters fit GT and CE carbon shafts. Are we aluminum shooters still out of luck?

 

Quote Are we aluminum shooters still out of luck?    

You'll have to get some JB weld and a blowtorch  

I build a string that fits the nocks.I have used boiling water to size them in the past and it worked fine.I thinned down a piece of wood slightly bigger than the serving on the string and just popped the hot nocks on it while they cooled to keep them spread.

BEST SOLUTION I'VE FOUND IS TO USE TWO NAIL FILES HELD TOGETHER TO DOUBLE UP THE THICKNESS. YOU CAN BUY A TEN PACK AT ANY DRUGSTORE FOR ABOUT 1.50.  SQUEEZE THE FILES DOWN INTO THE NOCK AND RUN IT BACK AND FORTH 2 OR 3 TIMES UNTIL IT FEELS LOOSER.  THE THICKNESS OF TWO FILES FITS MY STRING PERFECTLY.  PLUS IT'S ALMOST IMPOSSIBLE TO TAKE OFF TOO MUCH MATERIAL.  I SHOOT CE 350'S

I also reserve my strings to fit my nocks, it's much easier in the long run and you don't have to worry so much about one of those sanded or heated nocks blowing up! I have found reseving with fast flight material fits them well and gives me a real nice slick release!

Better to reserve the string to fit the nocks.

get the ultra beefy nirk nocks.  These guys can handle a little sanding and still hold up

With all the various size nocks available for carbon, aluminum and even wood.  Why risk modifing your nocks.  Some people may get away with it, but sooner or later you may get bit.

I have always used the boiling water system, both to widen and narrow the gap to a proper fit. The water has to be boiling and as already been stated, a ten second hold with nock only in water and kept in motion ( as in a figure-of-eight, or circle, etc. ), fit lightly to string keeping nock straight, and set aside to cool. I have never had one fail.

Like others here, I have been very happy with the boiling water method. 10-15 seconds covering the nock, then very quickly, I insert the back of my hunting knife, which fits the nock almost perfect, then gently and evenly, roll the knife back and forth to open the nock. Use even pressure as you roll the knife so the nock opens up symetrically. It doesn't take much pressure. Open too much? Back in the water and then pinch the nocks back together. You can tune your nock fit perfectly this way. Serving the string to match your nocks is also very good, but I find I always have to fine tune with hot water. Nock fit is very important!. Good luck. Dave

as long as it is a snap action nock there is no harm in sanding away some of each side of the "snap" as this does not weaken the throat which is I would say, the weakest point

only sand the areas right next to the opening