I don't use any lube in mine, it is such a tight tolerence it may hinder the machine when its new. But ,later on when it's been used for a long time it would close the gap again. I tried the machine with several types of lube when I built the first ones and found that using them dry was best. The plastic the piston is made out of swells in the bore from friction to improve the performance, ike knurlizing your pistons to fit the bore in a blueprinted race engine. I have the first one and I have never put lube in mine and I use it every single day. I try to break all my machines to see how long they will last. My brothers shop 3 different artists use the second machine 7 days a week and no lube as well for indurance. You can check his site out www.joedrachekicksass.com very long sessions and no problems so far. He's the bull in the china shop so to speak when it comes to tattoo machines.