Minoxers who built their own film slitter must encouter a question, what is the exact separation between two cutting blades ? They found out 9.5mm is too wide, it jamms.

I measured several factory loaded Minox film, Agfapan APX 25, APX 100, Minoxcolor 100 and the film strips cut from Minox slittter. It varies between 9.2mm to 9.3mm. I myself more lean toward the figure of 9.2mm. That was the film width figure I use in the thread "How to slit and roll your own film"

For practical purpose, if a slitted film width is between 9.2mm to 9.3mm, it runs in Minox cassette well, and still provides upper and lower margin of 0.6mm on each side. <

-- martin tai (martin.tai@capcanada.com), January 20, 2000

Answers

I believe a width of 9.3mm -0.1mm to 9.3mm + 0.1mm is close to the specification of Minox film width. Perhaps, under certain temperature, humidity condition.

-- martin tai (martin.tai@capcanada.com), January 20, 2000.

I just bought several rolls of Minopan 400 B&W film from MPL. It masures 9.4mm

-- Charlie Grant (grantseuro@hartcom.net), January 20, 2000.

Actually, some of the results of my previous posting of the "break- even" point in cost of film slitter cross into this area. In weighing the factors of which one to buy vs. build-your-own vs. not, tolerances for cutting errors are more critical the smaller the mechanisms. I'm competent enough to build a slitter from plans, but have found in the past that I'll go nuts trying to get things "just right". I don't own many power tools, nor a machine shop. If I value my time at $X/hr, trying to achieve an acceptable film tolerance will be expensive for me. Therefore, buying the precision slitter from MPL vs. making my own becomes less clear. We all have the same 24hr day, and I'm thinking I'd rather be outside shooting, rather than fighting a slitter & having film feed problems. Of course, the cost goes up, but there is an implied guarantee of the film working when purchased from MPL. On the other hand, maybe I need to have a "wee dram" 'o' scotch and chill out!

-- Jeff Drew (jdrew@westlandbank.com), January 21, 2000.

OK, I just measured some samples of processed and unexposed Minox film. The Minocolor II which was processed in '75 checks in at 9.23mm. I also have some unexposed Minopan "ASA 25 Ultra" that expired in '76 and it also measures 9.23. A roll of unexposed Tech Pan from Submini.com reads 9.11mm, and a processed strip of Tmax 100 from Submini.com reads 9.12mm wide.

All measurements made with a Mitutoyo digital micrometer and a Starrett analog micrometer. Both instruments gave the same measurments, within .01mm.

-- James Jones (jaj01@home.com), January 21, 2000.

After some consideration, I feel that defining only a width is not enough. Another equally important quantity is linearity, or how much a strip of 9.4mm film deviates from a straight line. Obviously, if a the edges of a film strip is wavy, even though at every point along the film, the film widht is between 9.1 to 9.4mm, this wavy film may not fit into Minox cassette. To measure the linearity or lack of it, we need to define a "film center line" as a straight line connecting the mid point of two ends of film. If a piece of film is absolutely stright, then the distance at every point of the left/right edge to the center film line = film-width/2. If the distance of left edge to center-of-film line is not equals to the distance of right edge to film center line, then line is not linear, by wavy. I think the deviation from straight should be <0.1mm.

-- martin tai (martin.tai@capcanada.com), January 21, 2000.

James's measurement of Minox film from the 70s indicates that at that time the real witth of Minox film was already substantially different from 9.5mm.

Any one has the measurement of VEF Riga Minox film of the 30s or 40s ?

Any one seen "9.5mm" used in Riga era Minox brochures, manual or advertisments ?

-- martin tai (martin.tai@capcanada.com), January 23, 2000.