[the4thseal]

I know I could buy air bearing. Though they are very expensive. I was curious how the man solved the problem. I would like to see how he solved it.

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PDFs was great by the way.

[mactec54]

I know I could buy air bearing. Though they are very expensive. I was curious how the man solved the problem. I would like to see how he solved it

He brought the Headstock Etc already made, he just epoxied some Granite parallels onto the Granite base, most of the parts where from the semiconductor industry, this is quite normal for that industry to have surplus used machines, that has all these cool parts on which can be had for very little money, especially if you work in that industry

[hanermo]

Japanese machine tool switches/sensors - accurate to 1 micron.
Glass scales, 1 - 0.1 - 0.01 micron (tbd).

Hi Hanermo

All very nice, but I can see one problem ahead: setting the zeroes to that accuracy!
How do you do that?

Cheers
Roger

[hanermo]

As a start-up point, I tested this with the centipede controller 5 years ago.
Optical switches provide about 1-2 microns homing accuracy, for 30$/axis.

The error was 2-3 microns, but always up by 1-2=> less than or EQ to 2 microns max error.

Probing should adjust this to 0-1 microns error, given I can get repeatability to less than 2 microns error.

.. Now trying to buy N4 nuts to fix the Z-ballscrew (bas***d thread, 20 mm / 0.8mm).
.. And making uprights for the VMC.

Hi Hanermo

All very nice, but I can see one problem ahead: setting the zeroes to that accuracy!
How do you do that?

Cheers
Roger

[the4thseal]

I understand what he said in the video. I know I can buy air bearings. My fascination is how he dealt with the unforeseen issues. I know he used purchased air spindles, I get that. He says "everything else he made. How did "he" make his air bearings? Can you buy porous carbon, or did he drill holes? How did he deal with the issue that air bearings creat?

[hanermo]

Iirc he bought the air bearings.
The porous carbon air bearing blocks are, iirc, 300-400 $ per piece (16 or more needed, I think he used 30+ (preload sides, etc)).

You can make them yourself.
A small hole, and approx 2-3x diameter/depth for air reservoir.

Ie 1 mm hole, and 2-3 mm D, x 2-3 mm depth, for the air reservoir at the surface where the air exits.
Smaller holes and more of them makes for tighter tolerances and more rigidity and less use of air.

Smaller holes/more holes => "better", somewhat.

Several have made air spindles, the air grooves inside were typically about 2-3 mm from memory, depth == equal to width.
Air spindles were said to work with 0.1-0.01 mm clearances, as long as the clearance was uniform.
Uniform was important.

[mactec54]

How did "he" make his air bearings?

He did not make them, the only main part he made was he put the Granite Parallels together, he modified some of the mechanical parts, to do what he wanted the machine to do, it was mostly made from an existing machine, he just added a few frills to the surplus parts he brought

To make your air Bearings, it does not have to be made from porous carbon, you can use any material you want even plastic

[LazyH]

I'm pretty sure in the video he says the only parts not built from scratch were headstock and grinder spindles. Those linear air bearings don't look mass produced and if he mentioned the spindles as being surplus why wouldn't he mention the linears too? That's just what I understand from his videos and comments.

[the4thseal]

That is why I would like to see how he does it.