So much to say. When I feel I need negative feedback, I ask myself if the seller deserves it. I have no intention of reducing sales, but then I think how much worse it could be for people using this exercise. This is the second exercise, the third I returned without trying. There's so much routine in these beats it's not even funny. You are literally chewing the material, not cutting it. Received the part in the mail, looked good. Put it in the press to test it and all I feel is a crazy vibe. I'm assuming it's my chuck or base plate. He did all sorts of tricks. No help. However, I decided to drill a test hole. The 18mm bit ended up with a nearly 19mm hole. WTF! You think this guy has a bad cartridge and blames the bat. Well I had an old professional racquet (I guess Amazon won't let me name it) that was too small but still 17mm. I'll go and guess what. No chatter, no vibration and the 17.98mm drill bit drilled a 18.01mm hole, I swear I'm not exaggerating. Both times the drills were lubricated during cutting. Of course, this is a cheap drill, but it's still too much. If you are tapping to tap later, you lose half the surface area. I share two photos. Once with this beat and once with the second brand. You don't have to be creative to see what's what. PS Boring the aluminum piston to check. Nice and soft.