Using a Davidson D-600 comparison autocollimator

[guythatbrews]

​I have a chance to pick one of these up locally. Not exactly sure how to use it to check a plate for flatness. Can't find much about the d-600 and I've searched a lot, and read about autocollimators. A copy of Advanced Machine Work will be here Monday and I'm hoping it has lots of good info about autocollimators in general.

Here is how I think it will work.

Using a reference mirror RM and a measuring mirror MM, keep the RM stationary and move the MM and note the angle difference between the two. I would use a straightedge to slide the MM along just to keep in alignment and make things easy.

It seems as "simple" as that. Am I on the right track?

It seems in some ways to be easier to use than a non-comparison tool, but I'm not sure about that either.

 

[ballen]

I've done surface plate maps with an autocollimator and with a Talyvel electronic level. For me, the electronic level was a lot faster and more repeatable.

 

[guythatbrews]

Autocollimator images through eyepiece

An electronic level is not on my list yet but may be later.

I did get the D-600 autocollimator and a D-638 as well, complete with light power supplies. Got two Davidson D-616 adjustable reference mirrors too. The mirrors are an inch thick, two-sided, and parallel within 1 second of arc for self proving. Every item is a work of art.

This pic is through the D-600 comparison machine. Pics taken by holding my phone cam in position over the eyepiece. I will try to get some kind of a setup like this when I actually use the AC because this eyepiece is in the horizontal plane and very tiring to use for one measurement let along many.

The left upside down t is the measuring mirror image. The right image is the reference image and if you look closely you can see a ghost image mirrored slightly to the right and above. When the mirrors are rotated on the plate the bright t's move along with their respective rings so I think the bright images are the measuring images. Not at all sure how to interpret this yet. I have no previous experience but images seem pretty clear and easy to read. From what little i have gleaned from others the excellent mirrors have a great deal to do with the clarity.

This pic is through the D-638 coordinate machine.

This autocollimator has a moveable optical microscope so the horizontal or vertical displacement can be measured, but not at the same time. This image shows the main reference line vertical and is set for measurement in the horizontal direction. You can estimate the displacement of the vertical axis by use of the concentric rings.

I am still looking for any mention of these autocollimators online and any experience anyone can provide. I've made and inquiry to Trioptic corp who bought Davidson Optronics to see if they have any legacy manuals, and also another place whose name escapes me. I don't hold out a lot of hope. I'm reading Optical Tooling For Precise Manufacture and Alignment by Phillip Kissam and it is useful but it deals more with jig transits and alignment telescopes. Advanced Machine Work does not deal with optical methods, but it is unusual in that it includes a ton of part examples with processes to make the part. Would be very good for a guy wanting to learn procedures used to produce parts.

When I get better set up I'll take pics of the whole schmeer. For now I jjust wanted to show the cool images through the eyepiece.

 

[guythatbrews]

Found manuals for D-600 and D-638/D-656

A place called Trioptics kindly emailed me pdfs of both these ACs. Just got them and haven't had much of a chance to read them yet, but they are just what I needed.

If anyone wants a copy let me know.

 

[guythatbrews]

I have THREE D-600 .. awaiting a 'round-tuit" to build new light sources.
I'd LOVE a set of the proper manuals!

Please use the PM 'email" feature to set up a channel to convey.

Some years back, I did manage to get what the LAMP VENDOR claims are the correct incandescent lamps for the D600 light source. They ARE a tad odd-looking, but I am still not certain they are actually the correct ones. Have spares if you can use a few.

I am hopeful I can go over to a tiny-source LED, but source size matters and so does wavelength, so that's only a "maybe".

TIA

Bill Hacker

I'll get you the manuals Bill. I was very glad to find them. I had about given up.

Here is a link to direct replacement cool white LED bulbs that seem to work fine. 10 bulbs for $8 so hope I'm good to go. Forever. But thanks. I used the 6v Davidson power supply that came with the D-638 turned all the way down. Didn't check voltage but the bulb didn't blow. Now I have a 2V Davidson supply but haven't tried it yet.

10 Pieces E10 LED Bulbs 3 Volt Miniature Flashlight Bulbs E10 Replacement Bulbs Mini Lamps Cool White - - Amazon.com

Greg

 

[guythatbrews]

Thanks for that link.

Part of my "plan" was to get shut of cords and use a battery pack, that "moved with the unit" even if it was a largish one. C or D-cells, even, not AA, AAA, or coin-sized.

The other part was to follow Rich's work downunder as to adapting a networkable (WiFI?) camera to the ocular of his English Hilger & Watts collimator.. so one can see the "doin's" on a conveniently large SCREEN .. and also "capture" the view.. instead of hunching over to get a Mark One human eyeball aligned and NOT having a publishable record of what it shows.

78th year, too stiff in all the wrong places!



Lots of other fish to electrocute before I get back to it, but thanks for those manuals, those could get the priority elavated a skosh.

I hear ya about using the old eyeball on the D600. It will even make a yoga master wince. And seems to be exactly zero eye relief, if not minus.

The cam is the way to go and wifi yeah. I will work toward that too.