Four prints but only one hit !

i made four prints yesterday evening on two printers.

but only one part made it to the end, the other part was printed three times and failed at 27%, 35% and 72% of the printing time.

this was not what i expected...
only one hand piece was a success!

pic will follow

the source for these issues: the adjustments for the first printer weren´t as precise as those for printer two. and the bed of printer number one was old and slippery. so i will change the print using a big raft under the to be printed part.