Mini35 Oscillating Ground Glass Idea

[Valeriu Campan]

<<<-- Originally posted by Dogus Aslan : (can some tell me how to put links:) -->>>
Great work Dogus!


For the links put the address between these tags
[url] [/urlREMOVE]
Please remove the "REMOVE" text from the second tag. No spaces inside and between the tags!!!

[Richard Mellor]

dogus your adapter looks beautiful . I bought bearings for my device and I used a bearing made by boca. a local bearing supplier had a bearing called KBC I think they are made in korea
the kbc were so much better than the boca bearings .
the shaft spins smooth as silk. just flicking you finger on the shaft it spins about 3 seconds. I don't think you need to worry about the ground glass so much I bought a 1500 grit from optmo sigma for the static device . but after seeing the glass used in the $26,000 ps tecknik . they used a glass with way more grain than
the 1500 optmo sigma I have. but I will bet the light loss is less
with their glass . once the glass was spinning it was invisible . so its seems that getting too fine a grain with a ocillating device .
would just lose light stops with no optical gain . the lens adapter was connected to a high def camera. so this would work with mini dv . you also might find.when I used two bearings per plate .
its would spin freeer than one . It seemed to keep the shaft more precisley true. between plates. if it is off even slightly the shaft and bearing will not spin freely

[Dogus Aslan]

richard can u send a few pictures on your design?

<<<-- Originally posted by Jesse Roberts : is anyone going to be offering these kits? -->>>

i see no reason why not?

-Valeriu

thanx pal... :)

[Dogus Aslan]

richard can u also give me any information on diemensions and the prices of the bearings?

[Richard Mellor]

hi dogus : The bearings that I needed were 8mm od/4mm id
they are made by kbc and the cost was$3.65 each. the company was a local place. I walked in and bought them at the counter
they have a web site but I don't know if they make small orders online. the website is actionbearings.com,

I havent finished with all the parts yet but this is the shaft I am using the bearings fit perfectly. a c clip on the bottom and the top of the shaft is drilled out so I can make a offset and screw it into the shaft . this part is made for a nitro car its strong and precise.

http://www.hobbypeople.net/gallery/554923.asp

when I am finished and all parts work correctly. I promise to give complete parts list and links

[Richard Mellor]

I wanted to complete this before I recommend purchases.

but this is something I found that I am buillding my adapter around http://www.surplusshed.com/pages/item/m2213.html the thorlab tube system is just too big to fit this I bought 3 of them the 8mm ball bearings are slightly smaller but the shaft is perfect length. this is a optical grade plate . I think it will be worth drilling 2mm bigger to fit the thorlabs tube system and I belive this will align perfectly .I think surplus shed has about fifty.
each plate will fit two 8mm od bearings per hole . there is room between plate 1 and 2 for pulleys and the third plate when drilled out will hold the tube system which can be adjusted to the 1.2 inch focal length

[Ray Zschau]

Richard,

Thanks for the heads up on that part. I saw it on their site a while ago while looking for parts for an Agus 35, and thought it could be a cheaper alternative to a couple Thor Labs parts. Are there any other items you're using in your adapter that may be in short supply? I'm still rounding up parts for that Agus, and now for an oscillating design, and would love to get as many of the parts as I can at one time.

Also, does anyone happen to have a frosted Maxell CD that they'd like to get rid of? I have about 10 clear CDs, but don't want to try and make my own GG. Some of them are quite thick, and look well suited for a homemade GG.

[Richard Mellor]

well I gave a link to this before . it can also be used for the tightening , the adjustment rings. in a tube system and filter rings .it will only go about 3/4 of an inch deep though http://www.surplusshed.com/pages/item/m1612d.html

[David Parker]

<<<-- Originally posted by Dogus Aslan : hi david...

i have mailed you twice but have recevied a reply that my ail was not sent..(the date can be seen on a few posts earlier)..

i am in the need of 2 pieces of 6cm diameter snow glass for testing purposes..can u tell me the price with included shiping to turkey?

and david...your grains ..what are there sizes scientificly? can u go finer?

thanx.. -->>>

Currently we are only producing square or rectangular pieces of ground glass, but I have started looking into the possibility of producing round glass pieces for this particular application.

So far I have heard there is a need for a piece of fine ground glass about the size of a CD, do you also require the hole drilled into the middle in order to proceed with your project.

I would really like to hear back from a few more indiviuals on this, I am sure I can produce a product that would work for the various applications, but would really like to have some more information.

Thanks again.

If for some reason my main email does not work correctly, I do have an alternative email address of fvww@flatheadvalley.com

I look forward to hearing from some of you.

I do hope I can help.

David Parker
Ground Glass Specialties
Satin Snow(TM) Ground Glass
www.satinsnowglass.com

[Brett Erskine]

Dogus-
Amazing pictures! You mentioned painting your adapter. Have you thought about powder coating it instead? Flate finish and if your using aluminum it much less likely to flake on you and get on your GG. What are your parts made out of anyways? If its steel instead of aluminum you might be heading in a world of trouble when you try and oscillate that kind of mass. Shaky video. Dont forget your thinking about using a glass focusing screen instead of a plastic one which will only compound the problem. Have you tested it yet brought it up to speed?

I like you retainer clips for the bearings. Good design. Rock solid/no slack hold on the bearings, right? Custom?

Also how are you attaching the belt and are you going to add grooves into the shafts to keep it on track?

As far as the Satin Snow Glass is concerned....Good stuff, heavy but very little grain. But not too little that it would be good enough to use in a static GG adapter but at the same time its better then any that I have been able to hand make. They are hand ground though (very nicely btw) but I waiting to see if they are consistantly ground enough that I wont get any strobing when put in motion.

Lastly I'm wondering why you have THREE plates with bearings. One off set and two static (in line). Couldnt one offset and one static do the same job. After all it looks like the two plates arent hard mounted together by anything other than the shafts. Doing so might make the system much more stable. Just trying to understand where your coming from. Good stuff.

[Dogus Aslan]

thanx bret..

the design is plain metal...i had the option to make it from aluminium but the price was x3..so i said i might to stick to metal for testing...aluminium is 5x leighter...in my first design i had parts that needed to be rounded..aluminum is more breakable than metal so i dismissed aluminium then..but now i have found a better way to make the part then to round it..so aluminum is a path still could be taken...i

i havent tested since i havent had time to find a suitable motor and also there is no belt yet...i have thought of making custom belt holder to be put around the mill and the motor..but still time for that...

i will change the bearings today..i have found some which are smoother than the ones i used..but i wonder about the boca bearings (something about the quality i read in there site..nice..)..but it wont be revolving too fast (like 60.000 rpm..this is the limits when u buy a good bearing) and wont have too much weight so...

the metal plates holding the bearings are cut with 0,001 mm (thousandth of a milimeter ) presicieon so i hammer them on slightly..but the metal plates have a 1mm width so there is a slight chance the mills will not be paralel..but putting the second plate on confirms they will all be in position..thats the reason of the second plate...i have gone into design where i also thought of using one plate which is thicker..but there is a approxemetly 45 mm length that needs to be constant between the gg and the slr lens..so i thought i still have plenty of space..ill stick to the 2 plate model...

yeah the mills are custom made..

i dont know what powder couting is? but i had in mind getting it painted to the guys who paint cars..i think its a kind of pray paint? but i dont rely know:)

[Brett Erskine]

Thanks. I hope you dont mind me putting in my 2 cents because I really think you have a winning design here and if we can perfect it you might generate enough interest to sell it. Obviously I would love one. At the very least if would serve as a ideal template for what to build others by. On that note I would recomend switching your GG plate for the same thing made out of aluminum. The other plates arent so critical. Also look into using high quality plastic GG or at the very least very thin glass. The bearings on the GG plate would most likely benefit from being extremely small - All for mass/vibration reasons. I hear the P+S Technik motor is a brushless motor so it might be a good idea to focus your searching there. As far as the belt - the P+S Technik has two rubber O-Rings. I guessing that they decided on using two belts because it was physically the weakest link in the system. If one breaks in the middle of a shoot you still have the other one. But keep in mind the more moving parts the noiser it is as well. Another O-ring shouldnt effect it too much at all though.

Keep it up.

-Brett Erskine

[Dogus Aslan]

brett thanx for the support pal :)hey i didnt start this 2 cent thing..we are all in it! i would love to sell this thing for whom who want...

after your post on the material i ordered cuts of the plates from aluminium..i left some parts metal as i heard that welding of aluminium is 10 times expensive than metal..i suppose i have to see for myself but for now..i share the same idea..the gg layer should be light, the other layers only increase the overall design, not the performance..

brett what is a brushless motor?

i have thought of gear's on the motor and the mill with a suitable belt.. i have made the design so that two belts can be put on the motor to two seperate mills..i think it differs with the mini35 design..they use the belt t o turn all the mills at once..i am planing to rotate only two..the third will be rotated by their tork..

about the noise, i had the idea that when i make this tool..i have to consider two things from the beginning..1- i have to buy an lcd screen and rotate it 180..2 i have to get an external microphone and recorder..

still i hope the noise will be reasanble...

[Bob Hart]

Dogus.

I think you'd better drive all three, otherwise, because of the short stroke and possible compliance in the plates/bearing/bearing mount, crankpin combination, it all might add up to enough lash to intermittantly lock the action causing momentary centers of grain.

David.

The varieties of the appliance fall into three flavours. Regard my following comments as general and without any authority on the subject. Other builders will have better information than mine.

One, the original low cost version used a clear compact disk which had been sandpapered. This disk was rotated to eliminate the coarse texture. This version became known as the AGUS35 after the initiator, Agus Casse.

A 5" CD-R sized disk with 15mm center hole would be required for this type. Except for the cost of the disk itself if made of glass, it is the least expensive of all the options as it is built almost entirely around salvage, but it is also the most bulky. If plastic disks are used, it is very inexpensive.

Construction quality can also be quite imprecise with methods ranging from plastic CD-R packs, silicone adhesive, radiator hose and joiners and gaffer tape assembled on kitchen tables, to precisely manufactured structures built in a workshop but still function effectively provided enough adjustment is permitted in the assembly for the optical center axis to be conformed to. (A version I built has an error tolerance of 5mm or 1/4" and will still work.)

The concept emulates earlier evolutions of the P+S Technik appliances.

Another, a fixed groundglass solution, eliminates any mechanical complications but requires a groundglass of exceptionally fine yet sufficiently opaque texture because the glass does not move.

This appliance by being made often from highly precisely machined optical components such as optical tubes, filter rings and adaptors lends itself from the outset to more satisfactory performance as a precise axis is maintained for the optical path. So far, the texture of the groundglass has been the drawback.

This applicance became known as the ALDU35 after the initiator Alain Dumais.

This concept emulates a fixed groundglass solution, the "Movietube". Groundglass sizes vary in diameter according to the clear metal framed optical filters people buy to grind one side of to create the groundglass. They are entire with no holes in them and much smaller than Agus disks, I think on the ballpark of 52mm filter mount size or maybe 58mm filter mount size.

A third version, which is the topic of this thread is also a moving groundglass design which emulates the later evolution of P+S Technik principles. The motion is orbital. Mechanical movement is very small. The groundglass size required is also small, in the ballpark of the 52mm and 58mm sizes but maybe even smaller.

This version, because it is made of precise components yet under development could yet lend itself to the use of square or rectangular groundglasses in circular frames and maybe the builders will define the glass to a common agreed size. This version also has the highest requirement for competent miniature engineering but uses commercially available components as much as is possible.


SUMMARY:

AGUS35 - Moving disk 5" with 15mm center hole.

ALDU35 - Stationary disk in frame 52mm - 58mm+.

Oscillating designs. - Moving groundglass. Large enough to permit mechanical excursions without edge frame intruding into image projection area.


FOOTNOTE:

Optical glasses tend to be in the ballpark of 1mm - 2mm. I initially thought a CD-R sized (5") glass disk more than 1mm thick would cause two problems.
Vibration due to difficulty in accurately machining and balancing a glass disk.

Gyro effect of large and heavy spinning disk causing the disk to move off the image plane during rapid camera movements.

Subsequently, I found when messing with the wax disks which were much heavier and 2mm thick (two glass disks), there was no unsolvable problem provided the rpm was kept at no more than 1500, the disk was balanced and ran true and the motor given more time to run up to speed.

[Dogus Aslan]

i am at the stage of finishing the design...i only have motor to select..can any one suggest any type or kind of motor (with reasons)?