Is "The Kid" related to Iggy

And, most of those WERE M heads, I think. They are MUCH lighter than the J head, no power feed, no back gear, but you got higher speeds with 6 belt grooves. I upgraded my round-ram M head machine to a

1J head, and while it is a true Frankenstein hack, it works a LOT better!

Jon

The M head may have been pretty good in 1938, but I had a lot of trouble with poor stiffness. The J head (although mine is QUITE beat) is just WAY stiffer. You really can tell the difference when using a boring head, but otherwise it still helps.

Jon

I did not start this bragging competition, and that's my excuse for posting the following: I just bought two "optical flats", 28 inches diameter, for $50 each plus auction buyer's premium. Then some company guy told me, Igor, do you know what you bought, I said kinda sorta, and he said, they cost a million dollars each, they had to grow the glass in a special chamber.

i

Ignoramus21475 fired this volley in news:SrSdnbm3Vf7ASyXMnZ2dnUVZ snipped-for-privacy@giganews.com:

Yeah, but Ig, they aren't worth a bunch of melted-down Mason Jars, if you can't sell 'em!

(I know what they are, and once in my life, I could have used one)

LLoyd

Faskinatin' stuff, Ig.

Sooo, what are you going to do with them? I'm guessing that laser interferometers (grabbed out of near-space) and other electronic wizardries have replaced the opticals.

Not for determining flatness. Small ones are used in metrology labs for certification, although I never heard of one that large, and I assume it's used for some purpose in optical equipment, not for measuring flatness of gages.

But that's just a guess.

Larry Jaques fired this volley in news: snipped-for-privacy@4ax.com:

Folks still use 'flats' to check other glass optics against; less and less, though.

The other tools are finally coming down in price to the point where optical flats won't be necessary at all in another 10-15 years (except for amateur telescope makers who grind their own optics).

LLoyd

That was my first thought, to repurpose them as telescope mirrors (assuming they are thick enough). 28 inches would make a pretty nice light bucket to play with.

Jon

So, do you think that I can sell them for something?

I thought, I would put them on auction.

Ignoramus21475 fired this volley in news:IbSdnQRs96r0eyXMnZ2dnUVZ snipped-for-privacy@giganews.com:

I really don't know. When I made my own diagonals for Newtonian 'scopes, I ground my own flats for interference-pattern checking.

With very little skill, and a LOT of patient labor, one can grind two mated hunks of glass down to within 1/8 wavelength of flat -- actually quite easily, if you have the time and are willing to put in the labor.

I think a prior post about their being useful as mirror blanks might be a good tack to take. A 28" mirror would be a killer amateur collector!

LLoyd

I am gonna sell them, that's for sure. One optical flat lays on styrofoam, and has some imperfections, the other one "Unertl" stays vertically in a super heavy enclosure, shielded by a locking shield, and looks perfect.

i

They used them to make huge cameras for spy satellites and spy drones.

i

Ignoramus21475 fired this volley in news:cJqdnSxdGI4GdSXMnZ2dnUVZ snipped-for-privacy@giganews.com:

Prolly not 'used' in the sense of being materials for those cameras, but rather to check flatness of other optics.

Lloyd

Keep in mind, say, if you make a 7" flat, and spend X hours of labor, a 28" flat would involve 16X labor. And more importantly, keeping the tolerance across a much larger surface is so much more difficult. Everyting works against you.

Right. They said that they purpose made satellites so that Democrats could spy on NRA members.

i

Ignoramus21475 fired this volley in news:lMqdndVBNa0lZSXMnZ2dnUVZ snipped-for-privacy@giganews.com:

I disagree. Except for final 'figuring' the labor to make a 1" flat or a

12" flat is about the same. It takes many hours, but the grinding proceeds at a rate corresponding to the linear material removal rate perpendicular to the surface, not at a rate dependent upon the area of the surface.

Think of it like plunge-cutting with a 1/4" milling cutter vs. a 1" cutter in the same material. It takes more horsepower to turn the bigger mill, but you still plunge at the same chip load (rate).

With grinding flats, the 'horsepower' is mostly supplied by the weight of the blanks. All you have to do is slide them back and forth (and figure

8s, and zig-zags) across one-another. But it takes little effort unless you get stupid and let the water between them dry out (DAMHIKT!).

Lloyd

LLoyd

Maybe you could sell them to IRS agents for spying on Tea party members.

Karl

great marketing plan!

I thought about that story and in the final analysis, it left a very bad taste in my mouth.

i

Do you know what material they are made of? Back in Washington State I worked on the Battlepoint Observatory. Their mirror is 27.5 inches in diameter and made of Zerodur, a extremely low coef of expansion material. They got the blank from Boeing , it was ground for some star wars project. So they built a grinding machine to regrind it for a mirror.

See

And see

for the directors. You might contact Malcolm Saunders about selling the flats. Ho might know someone who is looking for a large blank.

I am in a photo with John Rudolph on thils page.

Dan