DIY air bearing lathe

Wow. And his other videos, too. Wow.

About thirty years ago I worked on the controls for a machine (a giant, hyp er-precision photo plotter) that had a 6' x 8' slab of granite finished to millionths, that moved on air bearings. Very expensive, very cool stuff. I had forgotten about granite as a relatively inexpensive precision building block.

rangerssuck fired this volley in news: snipped-for-privacy@googlegroups.com:

You... um... don't own a surface plate; right?

Yeah... Granite has been around for quite a while as a "precision surface". Even your corner gravestone grinder can face a slab off to within a thou.

The only guy I knew in college who retired with a turbo-prop, paid-off home, no bills, and a good pension by the time he was 40 was a maker of blank gravestones. He did surface plates as a "fun sideline". The real money was in tomb markers. He used to brag that his grinder could do an

8' x 12' plate to within a tenth corner-to-corner. He said that was no trick, at all. The real trick was getting it on and off the bed!

(and yes, he had the whole volume of space around and in the grinding zone temperature-controlled). Even the water was pre-heated or cooled to EXACTLY the stable resting temperature of the work. He had it nailed!

LLoyd

LLoyd

LLoyd

"Lloyd E. Sponenburgh" fired this volley in news:XnsA460BC38825BClloydspmindspringcom@216.168.4.170:

Sorry... I have no idea why I or it did that. 'L

Yes, I do own a surface plate. I was talking about actually building stuff (other than buildings and gravestones) out of granite.

As I recall it, the people making the large slab could only work on it a couple of hours a day towards the end of the process, as the friction from grinding would heat it up too much.

Good thing that gravestone guy is already retired. I hear that the gravestone business is dying. (sorry).

rangerssuck fired this volley in news: snipped-for-privacy@googlegroups.com:

I was always pissed at him for that. He was a B- student, barely got the credits to make his BS. But he was an A+++ granite grinder! And apparently, he knew where and how to sell his wares.

Lloyd

How many of us can be sure our work will still be on display 100 years from now?

Best regards, Spehro Pefhany

Spehro Pefhany fired this volley in news: snipped-for-privacy@4ax.com:

ME! I have a pile of rejects and botched jobs that won't fully decay for at least a millenium!

Lloyd

We thought perhaps -all- your personalities replied at once. ;)

That's the way to do it: find your niche, find the right contacts, do the work right, and make millions.

In one particular venture (past present or future, something like that), I'm holding out hope to live on as a small part of a Harvard Business School case study of what not to do in a tech start-up.

Best regards, Spehro Pefhany

If you want someone to constantly criticize you without offering solutions you could just get married.

Wow, that's very cool. It reminds me of another air-bearing, granite-based lathe made in the '80s, from Pneumo Precision (now part of Corning). It was built for diamond-turning optics.

BTW, I can't see what linear motors would do for it. I see that Dan Gelbart has a bunch of interesting videos there. He appears to be one heck of a craftsman.

Also BTW, those dynamic air bearings were used on internal toolpost grinders back around 1910 - 1920. That's an interesting story in itself.