we have a new haas lathe and there has been a very big problem with the chuck holding. it keeps pushing parts. and or spinning it. has anyone else had any problems like this or is it just this lathe?

Have you checked the hydraulic pressure? You do not mention which lathe it is; we have SL10s with hydraulic chucks that run at 250 psi and a HL1 Big Bore machine that runds at just over 300psi. The adjuster on the SL10 is difficulty to see because it is up inside the covers; two black knurled knobs, one is the lock nut one is the adjustment. Screw it in a very small amount and watch the pressure, it is almost certain you will overshoot because the response is dleayed. Do a few chuck cycles and recheck.

Another source of poor grip is the chuck getting filled with small chips impeding the drawtube motion but on a new machine that does not seem likely.

same prob here we have SL20s parts chattering at 1700RPM losing hydraulic pressure

have you got this fixed ours a sl20 also. the chuck just dont hold the part can be pushed right down the spindle. Haas gave us different jaws that are sharp but they dig in not to good for a finished part!

if your part pushing..recut the jaw 0.3mm using boring bar or increase the hydraulic pressure to 300psi