Air Bearing Plans

[bgmnn]

I am interested in building an air bearing fixture for the resharpening of end mills. I understand there have been articles published pertaining to this type of project.

Any of this information available online or is it only available in print?

Thanks for your help,

bgmnn

[mixdenny]

I've worked with a few different air bearings, from large load movers to precision turntables. What advantage would it have for sharpening an end mill, don't you just grind one flute then rotate to the next one? The air cushion thickness depends on the load, wouldn't it allow deflection while grinding?

Dennis

[toastydeath]

My company makes air bearings, so I can't give you any design information.

Air bearings are very rigid. The gap does change, but the forces required to do so substantially are high enough so they bend the surrounding material as well. If you are substantially changing the air gap, your underlying frame is bending as well, and far more than the bearing itself. The bearing is not the weak point. We make a bearing system with no clearance, and when the bearing is turned on, it creates its own preload by bending the frame it is housed in. Turn it off, and the spindle is clamped.

They work for grinding fixtures because an air bearing bushing (what you would use in a grinding assembly) has not only rotation, but will slide freely as well. You can rotate the endmill for alignment and sharpen the length of the edge with one fixture.

Air bearings also leave the best possible surface finish for your given cutting parameters. You get a sharper, more constant edge when you use air bearings.

Insofar as design, read Alexander Slocum's Precision Machine Design. It has a whole section on the design and construction of aerostatic and hydrostatic bearings.

[mixdenny]

Ah, I hadn't thought about the sliding part as the air bearing, that makes sense.