Air bearing steady rests??

On another thread sombody mentioned air bearings for a steady rest, I didn't want to hijack his thread so here I am. How effective are they and what are their limitations? Are the capable of supporting heavy turning operations and how does one go about sealing the face of the bearings to the work piece. Cheers.

faces the same problem as any other shaft supported by fluid: compensation, the normalization of the pressures supporting the shaft.

a steady want to approach and retract the supports, preventing labyrinth style self-compensation. Porous carbon pads can retracted, but cost like 500USD for 1 block of 2x3", and would only fit one radius.

Ah thank you. It is not something I had heard about presumably this is why I have never seen one, with such prohibitive costs. Thank you for your response.

steady oil supply

smoking-swarf said:

On another thread sombody mentioned air bearings for a steady rest, I didn't want to hijack his thread so here I am. How effective are they and what are their limitations? Are the capable of supporting heavy turning operations and how does one go about sealing the face of the bearings to the work piece. Cheers.

Click to expand...

.
if you use brass tips on steady rest it will quickly wear to diameter of bar supported preferably at least 50% of circumference supported. if a way of a drop of oil on steady rest supported area is made i think it helps a lot. something as simple as a coffee can with pipe fitting on end and a needle valve should not cost much. you see pictures of old lathes with cutting oil applied like this or a can with a drop feed adjuster on a rod a couple feet above lathe ways usually attached to carriage but maybe attached to steady is better for supplying oil to steady
.
not air supported but oil supported. trouble is most machinist do not want to make something up to apply oil at 1 drop per second at steady rest.
.
and if machinist do not want to bother making up a oiler than who is going to make up or use a air bearing steady rest ???

Alternate steady rest is a bearing cat head. ThinK of a 4 jaw steady - chuck, with the jaws adjustable for centre but the spin with the work. IE work is clamped into the middle of a rotatable bearing, not cheap to do at larger diameters, but gets around all the failings of your typical steady rest. Whilst adding a few of its own!