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View Full Version : roll film mechanisims?



Jeff Mack
02-18-2005, 06:26 PM
Was thinking of trying to make a cam that could use 6x6 120 film. Does there need to be tension on both spools keeping the film tight? If so, how do you maintion the tension?

Thanks!
Jeff

ImageMaker
02-18-2005, 11:27 PM
It's a good idea to have some tension on the film -- though flatness doesn't matter much in pinhole, getting a tight roll on the takeup spool helps a lot in avoiding edge fogging from light leaking around the backing paper.

The simplest way to keep tension is the same way a lot of old commercial cameras did -- with a smooth surfaced spring that bears against the roll, one at each end. You don't need a lot of tension, just enough to keep the film and paper rolling fairly snug on the takeup side.

bino
02-19-2005, 06:46 AM
I have done it this way:

Attached files http://f295.f295.org/uploads/k2a_3801.jpg (http://f295.f295.org/uploads/k2a_3801.jpg) http://f295.f295.org/uploads/k2b_2061.jpg (http://f295.f295.org/uploads/k2b_2061.jpg) http://f295.f295.org/uploads/k2c_8050.jpg (http://f295.f295.org/uploads/k2c_8050.jpg)

Jeff Mack
02-19-2005, 11:39 PM
Perfect. Thanks so much.

Jeff

suttonjp
02-20-2005, 10:55 PM
Bino,

What are you using for knobs on that camera?

ElrodCod
02-21-2005, 09:13 AM
It may be difficult to see in this photo but it is essentially the same as in Bino's camera.

Attached files http://f295.f295.org/uploads/cameras3_1644.jpg (http://f295.f295.org/uploads/cameras3_1644.jpg)

ImageMaker
02-21-2005, 09:36 AM
Bino,

What are you using for knobs on that camera?

Looks as if Bino might have access to a machine shop -- those look like lathe turned aluminum knobs. I might just have to get a scissor knurling attachment for my lathe so I can make nice knobs from aluminum or brass when I'm ready to make a roll-film pinhole camera.

bino
02-21-2005, 05:58 PM
Thank you, ImageMaker, you are right. Knobs are lathe turned aluminium. Can`t find the right word, because I only have one word-book "English-Deutsch". Maybe better to buy one "Deutsch-Englisch".
My son made this knobs, because I build the axle with 8 mm diameter. When you take an axle with 6 mm diameter, you will find a lot of nice knobs ready. They are in use on electric maschines or find them on old radios on the fly-market.
The next camera I made ( K3 ) has 6 mm axles and ready knobs. Works well!
Ready knobs have a lot of different forms, different colors etc. So you can make an excellent design,- if you like.
Ready knobs you can get for 4 mm axles too. I think that`s to thin. :)

ImageMaker
02-22-2005, 07:35 AM
Bino, I like the idea of lathe turned knobs and metal work in general -- I've been working this week on making a lens board from sheet brass to fit a baby Century Graphic (the 6.5x9 version). I might just have to make some camera stuff from brass, too (though thinner brass than the .75 mm I'm working with now would probably be perfectly fine). The wonderful thing (to me) about having machine tools is the ability to make my own parts as needed.

Yes, Deutsch-Englisch would probably be more useful for posting than Englisch-Deutsch... :)