Can buy one of these, and make your own thread protector, if you like: https://www.mcmaster.com/nuts/thread-size~1-1-2-8/
Some minor modification to make it just what you want for popping the collet sleeve back out.
I've mentioned that I'm a cheap bastrich, right? You could make your own, if you can cut 1-1/2-8 internal threads yourself, too. I can't yet, Couple more lessons in class to learn that. Anyone care to guess what I'm going to be making when I'm supposed to be working on the class project? Also need one for my SB Heavy 10L, with the 2-1/4-8tpi spindle nose. I have already made stub spindles for both machines so I don't have to go to the machine to test fit stuff I make for it.
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)