Originally Posted by
cnctechguru
Have not worked with a vmc 906, but have extensive work completed on vmc 4020 and vmc 6030 machines. From the spindles that I have changed (10K rpm, posi drive belt system) it is important to make sure that you line up the timing marks on the pulley to the mark on the spindle shaft. I believe the are three marks on the pulley. This alignment is dependant on which tool changer you have. And, when you have the spindle back in and ready for the pulley, you have to make sure that you have the pulley set to the proper height. I have a piece of flat bar that is machined to a height of 1.668". (Not sure if this is the same for the six belt vs. pozi belt)Set that on the casting of the z-axis, and then heat up the pulley. Slide pulley onto shaft, and let it rest on the flat bar until it is cool. I recommend locking the spindle so it cannot rotate. This makes it easier to get you marks to align properly, before the puley cools, and you cannot rotate the pulley. Good Luck, Eric