I have done this technique for the past 40 yrs with good success. It’s fast and easy…
I simply boil some water as others have stated and insert the nock of the arrow into the water for approx 2 seconds. Immediately – I nock the arrow onto my bowstring and push and pull the arrow on and off the string to ‘stretch’ the nock open more if need. After doing this approx 8-10 times I allow the nocks to cool or run them under cold water for 30 secs to ‘set them up’ – and then later retest again for fit.
I once read that if a nock fits properly – it should stay ON the string unless the string is ‘slapped’ pretty hard by your hand – and then – should simply pop off. If they don’t – then simply repeat the procedure until they fit as desired.
This has always worked for me. Just be careful NOT to overheat the plastic by leaving the nocks IN the boiling water for to long of a time.
