My Nitecore D10 SP was been a bit of a disappointment out of the box. It stopped working for no apparent reason on two occasions when I first got it and the piston drive was SUPER stiff. The piston drive was very slow to return (due to the super tight o-ring), and I believe this could be a factor in the unreliability of my light. This also made it hard to get to the strobe and SOS modes since the piston moved so slow.
I searched on how to alleviate the stiffness of the piston drive and read (here on CPF) that people sand the o-ring with fine grit sandpaper. I decided to try this myself and lo and behold, this light has become much much more pleasurable to operate! My thumb no longer gets a sore from operating the piston drive and there is no flickering or malfunctions of any kind like I used to get as that piston oozed back into position. Pressing the PD now results in a very positive click that is very satisfying and confidence inspiring compared to the way it was. I can now easily access all the modes quickly and flawlessly. If anyone was wondering about doing this as a fix to a stiff piston, I highly recommend it. I can now say I love this light.
I searched on how to alleviate the stiffness of the piston drive and read (here on CPF) that people sand the o-ring with fine grit sandpaper. I decided to try this myself and lo and behold, this light has become much much more pleasurable to operate! My thumb no longer gets a sore from operating the piston drive and there is no flickering or malfunctions of any kind like I used to get as that piston oozed back into position. Pressing the PD now results in a very positive click that is very satisfying and confidence inspiring compared to the way it was. I can now easily access all the modes quickly and flawlessly. If anyone was wondering about doing this as a fix to a stiff piston, I highly recommend it. I can now say I love this light.
