Modification of flywheel?

Many of the project pages I’ve been reading talk about getting the flywheel machined to lighten and check balance. Is this highly recommended, or just an optional type thing?

It’s always a good idea to have your flywheel machined if you would like to improve efficiency. The energy lost by momentum shifts is unbelievable. An example is: when we have a part in a lathe that is slightly off center, the spindle load with no cutting is somewhere around 38% for a flywheel sized piece of Al. Once the part is concentric, the load goes down to 7%. Turning down a .150 depth of cut in 7075 at 20ipm only brings the load up to 25%… just food for thought. :smiley: