Why is my Nitecore D10 piston sticking?

I have the Tribute edition Nitecore D10 and I wiped off all the factory grease. I also used some Flitz to polish up the piston. I then used the dialectric grease from Autozone, and wipe a small amount around the o ring with my finger. I seems that when I first try to turn it on and off it sticks a bit. Once I press it maybe 15 times it starts stops sticking.

Any recommendations?

Should I change the lube or use more/less?

get rid of the di electric grease. Its way too sticky for this application. Its not for this type of application at all. Its mostly meant to keep moisture out of connections to avoid shorting and corrosion.

Superlube is what I used for mine. Wipe all the grease off the piston and the inside of the tube.

There is a sticky somewhere that lists all the greases that work the best for lights.


The switch ring is what returns the piston and that is most likely what is sticking. Mine did it as well. I took the switch ring out and polished the outside of it with my dremel and then lightly lubed the outside of it with superlube. It is smooth as silk and never gives me trouble. My EX10 was a pain when I first got it but now its 100%.

Edit one more time: The reason its sticking is that Nitcore made a poor decision and turned the outside of the ring and the inside of the body with the same feed rate on the lathe. This creates tiny interlocking ridges that can grip and cause way more than mere friction for the spring to overcome. They need to run an odd ratio like 3 to 1 to avoid matching up the ridges. By polishing the outside of the brass ring it removes most of these ridges and allows very nice smooth action.

What batmanacw said, but pay special attention to cleaning lube off the inside of the outer tube. I use q-tips to remove lube from the shoulder around the hole where the piston button goes through. Lube left on that shoulder seems to me like it creates a vacuum.

I never had to go as far as polishing the brass contact ring in the head, but a small application of deoxit or the super lube will do wonders for helping the piston action.