Re: [CAD_CAM_EDM_DRO] shafting question

Rick Miller wrote:

> Hi,
> Could anyone point me to a resource telling me how much a certain material will bend if it is X long and has Y load applied to it? I'm trying to decide if I can get away with using 1/2" dia. end supported shafting on my mill or if I'm going to need continuously supported shafting.
> I'm concerned the end-supported may bow too much under load, causing innacuracy or leading to things binding up on me. The continuously supported shafting though is much more expensive.
> Also, has anyone had any experience using frelon bearings?

There's no need to do the calculation, 1/2" is WAY too flexible for machining.
I'm using 1/2" end-supported shafting in a laser photoplotter with a carriage weighing
less than 1 Lb. I had to put in a foam pad for damping, because the vibrations
from the stepper motor set it ringing. There's no way a couple of 1/2" shafts
could support even the lightest of milling operations with an extension of more than
6" or so. unless your spindle will be a Dremel tool, I think you should forget 1/2"
altogether, and go for at LEAST 3/4". You will still have a lot of play under light
load. But, then, maybe I'm spoiled by my Bridgeport.

Jon