I've just built myself a prototype, and I fear that the motor will have big problem putting the three shafts in motion. What's the big secret of having the shafts running as smooth as possible? ..

This brings me to my to next question .. For those of you who got a working model: Are you able to turn just one shaft by hand, when the GG plate is on?? I was able to do this with my prototype .. One reason for this could be the fact that I used plexiglas instead of aluminium .. or because the holes for the bearings wasn't perfectly aligned .. or maybe my shafts needs to be more off-centered ( today they're 1mm off )

Another thing that struck me a while ago.. Isn't there a chance that the three shafts will go out of sync? Especiallly if you move the GG plate in a small radius? .. Any help appriciated!

martin can u show us photos of your prototype....

if you think about..you are making a plate that is held by two eccentric shafts...for the system to run perfectly the shafts have to mimic the same motion...if one shaft of the two is not paralel..or impositioned..its impossible to get the plate to turn...when you have 3 shafts you have more importance..

how did you cut out the holes for the shafts?

"This brings me to my to next question .. For those of you who got a working model: Are you able to turn just one shaft by hand, when the GG plate is on?? I was able to do this with my prototype .. One reason for this could be the fact that I used plexiglas instead of aluminium .. or because the holes for the bearings wasn't perfectly aligned .. or maybe my shafts needs to be more off-centered ( today they're 1mm off )"

..can you eplain what you ment...

good to see new people in :)

Hey Dogus!

Yeah, that's true .. the holes needs to be perfectly aligned .. For my next try, I will drill the holes on all three plates at the same time, thus making sure that they are aligned .. I didn't do this on my prototype .. so .. shame on me .. :)

Btw, I saw your pictures on your model! It's looking really good!

Well, I just wonder what happends when your turn one shaft by hand, when the belt and GG plate is on? Do the two other shafts start to move as well in the same direction?

yes when i turn one shaft the other shafts turn..the reason for this is in the way the parts are been built...

take a look ..

www.us.trumpf.com/31.tc3030-4030-6030.html

i have done my designs on cad programs and i got them cut out on this thing...it is 1/100 mm accurate (hundrath of a millimeter)..in my design i have two plates holding the shaft ...so the shafts have no escape but to stay inline!

Sorry for the OT.


Dogus : I work for PrimaIndustrie :D

http://www.primaindustrie.com/

hey Dario! u r the man:)

i need to ask u 2 things..

1- whats OT?
2- for the ground glass we all have been trying to get..i was wondering if a laser so delicate could create marks on the glass..with very small distances..so we could have a very fine ground glass?

I think people found that when you get too fine the glass starts to reflect light. That's just a faint memory though.

OT = Off Topic :)

Cannon has laser etched GG in at least one of their Pro cameras these days. Last time I checked none of the optional screens were without markings so - unuseable. They are incredibly fine grained though. Better than even Satin Snow Glass. Perhaps if you talk to the right people at Canon you can find out who makes them for them and have a plain one done. I tried getting them on the phone but couldnt find anyone who could get me specifics. But if you have someone else make one tell them that you need a "random" grain structure done because normally lasers are so acurate that they will produce a extremely fine pattern and you dont want a perfect pattern. It can have a moire effect with the cameras CCD.

-Brett Erskine.

<<<-- Originally posted by Dogus Aslan : hey Dario! u r the man:)

i need to ask u 2 things..

2- for the ground glass we all have been trying to get..i was wondering if a laser so delicate could create marks on the glass..with very small distances..so we could have a very fine ground glass? -->>>

No, the main problem is not the radius of the laser beam, but the heat it will generate. The way (I believe someone is doing it already) is to use waterjet machines. They trow an high pressure water jet, mixed with abrasive diamond sand on surfaces, usually to cut them but it's also possible just to mark 'em.
I believe buying a big glass plate and marking all the surface then cutting it with the same job whould cost really really less than buying pre-made ground glass.
Let's say with the price you'll spend for a single groundglass you can mark and buy and cut something like 1x1 meter plate.

I will contact Finnpower or Waterjet (two of the most famous waterjet machine producers) and ask them.

I saw in a show here in Italy machines cutting optic glass (that's always due to temperature, water cuts at ambient temperature).

I'll let you know.

Progress anyone??

http://www.sunrushmusic.com/micro35/micro35test.htm

Hi,
I haven't been following the thread for a while, so I'd like to know if any of the other efforts besides mine have generated sample footage ?

How about those parts that were cut on a very expensive laser machine the size of a small house.... got footage yet?

-Les

hi les...i think the small house design ur talking about is my small house:)

i have got good results..but the design had a problem when running it too long the glass layer part tended to lose position making part of the projected image blurry...

i have brought the design to a master in micro mechanics and design, and we have agreed to take the design from the begining..only this time better!....the presicion is very high..i am hoping alot will like the overall product..

i want to publish pictures from my new design, but this will take a few weeks...it is going to be interesting, there arent even any bearings in the design!

Oh OK,
I know from my experience that if the shaft alignments are not perfect, the glass holder will want to walk away from the shafts as it all moves. My second attempt at the shafts fixed that problem. I still had a very slight image vibration in my HD demo, however.
I also have an idea that does not use standard bearings at all. I've just got too many projects on the list right now!
-Les

Les.

I don't know how it goes for NTSC and 24P over there but with the simpler numbers in PAL country of 50 / 25P, you may find that if you shoot interlaced, then apply the motion signature recipe which has been published on this site, the vibration may go away although you may get a much slower weaving effect somewhat like a worn projector gate with film.

I most recently encountered a similar thing with my AGUS setup when I tried to mount the combination to a very firm tripod. An out-of-balance condition of the disk did not make itself apparent when the combination was hand-held or on light MiniDV tripods but with the big Miller, the vibration instead transferred to the camcorder body just enough to move the image on the CCD about one TV line.

Hi Guys,
Here is my last attempt (of 23) to solve the GG movement.

http://pictures.care2.com/view/2/941356005

http://pictures.care2.com/view/1/682555803

Please consider the size (24/36mm ! ) small power requirements,
variable speed and variable amplitude of movement, noise, weight,...... and if you
have an idea of how it could be improved, let me know please.

Regards,
Dan D

I emailed Thorlabs and asked them if they sold anything which could rotate a 2" gg and they gave me the following link:

http://www.thorlabs.com/NewGroupPage.cfm?Guide=121&Category_ID=183&ObjectGroup_ID=1064

Would it work?

Not for the GG.
This one can rotate "something" very precise (1 arch) but the roation
has a central axis. (Like P+S first run)
And the motion is fragmented (stepper motor)
Not to mention size and weight, oh yeah and price.

As many of you know, several months ago I built a 3 shaft GG orbiter and did a quick HD ( 720 P ) demo video posted at 7.5 megabits/sec. Many of you saw the slightly shaky video before my bandwidth was used up.
In preparation for making a small run of these as a parts kit type of deal, I also wasted a lot of paper coming up with other methods of moving the glass. I think I have a possible solution now. It still involves some very precise machining, but it simplifies the design considerably while still supporting the mechanism on precision ball bearings. I tossed ideas that slide the glass on a slider surface because of longevity concerns.

I just got my CNC mill up and running, so this weekend I'll test the the core of the design out a bit. I use a laser to test image plane stability.

Maybe the 45 micro bearings I just purchased for the 3 shaft design will have to be re-purposed now ;)

Cheers,
-Les

Nice Les! Keep us informed! I've got a cnc mill and lathe collecting dust! It's calling me!

Anyone know of a source for inexpensive (yet reliable) ball bearings? BocaBearings.com seems to be a bit expensive.

I am looking for something with a 50mm inner diameter. The outer diameter isn't critical.

Thanks for any help!

It depends upon too many factors: what kind of balls, ceramic, steel, nonmagnetic, quantity, etc.
Try these guys:

http://www.canadianbearings.com/publicSite/content/products/productCard.aspx?Lang=en

Most likely, you will find something suitable.
For larger quantities here:

http://www.xlbearings.com/

For one or two, most cost efficient is scrap yard (used cars)

I hope this helps.

Thanks, Dan!

I'm looking for something lightweight, and preferably with a flanged inner diameter.

I'll try the sites you posted!

I'm wanting to move from using masking tape to mount my 35mm lenses to using a more permanent, professional looking mount. However, I don't want to use something that will work with just Canon or Pentax, for instance. I'd like to go with something that would allow me to use a variety of brands/types.

I understand T-Mount converters are pretty cheap, but to implement this, what sort of mount would be on the adapter in the first place? Would I just go with, say, a Canon mount and any time I needed to use a Pentax or Nikon lens, get the respective T-Mount for each?

I'm not a 35mm expert, so please forgive my ignorance. Any help is really appreciated!

-Frank

Les.

Bearing inside another bearing in an eccentric ring? Would probably need to be two rows of each otherwise would need at least one guideplate. I would suggest magnetic if one row of bearings is used and guideplate is added to keep it faced with minimal friction.

Also suggest you use a double "O" ring belt drive for the outer eccentric and two "O" ring belts as anchors for the inner which carries the groundglass. there may be a little rocking but nowhere near that of a sliding radial keyway.

Truck axle should be adequate for machining the rings and the ball tracks. Drill out small reliefs to lose some weight and also to counterbalance the eccentric ring.

I would suggest something in the approx. size of loose 1/16" bearing balls or thereabouts whichever is the most commonly available. Alternatively you might get away with needle rollers from automotive driveshafts but these would need more power to spin them and a guideplate would be mandatory.

Keep on designing.

<<<-- Originally posted by Frank Ladner : Would I just go with, say, a Canon mount and any time I needed to use a Pentax or Nikon lens, get the respective T-Mount for each?

I'm not a 35mm expert, so please forgive my ignorance. Any help is really appreciated!
-Frank -->>>

Yeah that would do it. You'll have to figure out a way to get the SLR mount on your converter but once you solve that you'd just buy the lens adapter you needed for each lens type.

I got a lens mounting flange off a macro tube. It was simply screwed on there. Or pick up a broken camera and screw off the flange. I used brute force at that point and used epoxy to attach my mount instead of trying to tap tiny screw holes. It's rock solid though :-)

Thanks, Joel!

I have an old camera body I can try.

Ok, I took apart an old Mamiya 35mm camera body that yielded some good parts. I must say, they don't make em' like they used to. I was hard-pressed to find any plastic in this thing. It was all metal, right down to the miniature chain on pulleys.

Anyhow, I got a mount which I think is a M42. For now I will use that instead of getting a c-mount for Canon FD lenses, since I have three lenses that fit it. Plus I could just get adapters for any of the other lenses

One of the best things to come out of it was the little condenser. I tested this out on my microcrystalline wax adapter and was very happy with the image. It gave a bright picture from corner to corner. The only problem is that the condenser is small (24x36mm), so I wouldn't be able to use medium format lenses, or take advantage of the extra image projected from 35mm (not having to zoom in as much which ground glass this means smaller grain). However, even at this magnification, there is no grain with microcrystalline, so it might work just fine. I will try and put up some more test footage.

Here are some helpful links that deal with different lens types, t-mounts, etc...

http://www.photoimagenews.com/lens.htm
http://medfmt.8k.com/bronmounts.html

Rai,
It seems you would have to hit a very low price to interest people on this forum. I offered a kit for a 4 shaft 12 ball bearing kit, with motor,belt, misc parts to make a complete GG orbiter for $350, and there was ZERO interest. It's not a pipe dream on paper on my end, as my posted pic have shown.
Perhaps a price of $100 might work here. Or maybe we let them try to make one for a while, and then see what happens :)

It's *not* the cost of the parts. The labor of making the custom parts is the price here.

-Les

I'm new to the forum but have read thru many of these threads. While ideally i'd embrace the idea of building an oscillating gg on my own, the reality of everything else I have to do makes it improbable that I would finish (or start;). 350 sounds like a steal to me, i've blown more money on things of much less worth.