Film-Tech Forum ARCHIVE: JJ switch 35-70 and back again question

This is topic JJ switch 35-70 and back again question in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jim Henk (Member # 3628) on 05-13-2013, 03:17 AM:

When I was being shown how to switch the Century between 35 and 70, the only thing that didn't make any sense to me was the intermittent shoe. One must be removed, and the other installed, of course. Fine. But I was shown that the only way to do this was to first remove the intermittent in order to be able to get at the little screw at the base of the shoe assembly that holds the tensioner nut from backing up and out. (presumably from all the vibration)

True, it seems like the only other way to get at that screw is to have the world's smallest screwdriver, like one inch long total, because there's lots of other stuff in the way.

But it just seems so wrong. I can't believe that Century would make a unit with such a tricky operation necessary just to switch film media types. Yes, I've had to learn how to do it, but I remain extremely skeptical. What am I missing?

Posted by Louis Bornwasser (Member # 3063) on 05-13-2013, 06:05 AM:

Don't know what is going on on your unit, but. . . . normally tools are not needed to do that. It just "plugs" in and out. Probably a ball-detent. I've never disassembled that particular portion. What you describe is almost right for an SA (35mm) unit.

It would be somewhat easier to replace the screw with an Allen screw and use a small ratchet. Louis

Posted by Steve Guttag (Member # 268) on 05-13-2013, 06:06 AM:

Your information is incorrect. Open the shoe. Grasp onto the intermittent shoe assembly via the knurled knob sticking out at you and pull it straight towards you. the whole assembly comes out. Get the other format and push it in and it will click right in. The whole operation takes about 5-seconds.

Posted by Jim Henk (Member # 3628) on 05-13-2013, 11:22 AM:

Crap. Mine doesn't do that. Rebuild folks must have missed something. Nobody's perfect. Will have to have somebody look at it.

Posted by Richard Hamilton (Member # 321) on 05-13-2013, 11:54 AM:

page 17 of the manual gives you the instructions. Sounds like you have the wrong intermittent.

Rick

Posted by Jim Henk (Member # 3628) on 05-14-2013, 03:02 AM:

Thought about it, but doesn't make enough sense. Did Century make more than one intermittent housing with an opening wide enough for 35/70mm sprockets? This one definitely does.

Posted by Louis Bornwasser (Member # 3063) on 05-14-2013, 08:48 AM:

It is possible that "things changed" over the years as Strong forgot how to make JJ's. Steve is right, all JJ's had the plug in mount with a roll pin through the hole and a detent on the side. Possibly Strong made one just like the 35mm only intermittents with a simple set screw on the side, no roll pin or detent outof habit. Louis

Posted by Steve Guttag (Member # 268) on 05-14-2013, 11:57 PM:

It is also possible the screw with the spring ball is too far in or the ball is stuck and it only appears to be fixed.

I'd explore it a bit further.

Posted by Jim Henk (Member # 3628) on 05-15-2013, 12:30 AM:

Yep. Have already called the folks that did the original re-build of the innards of the intermittent, and they want to see it. (just have to find a day to break free from the job...)

Many thanks.

Posted by Jason Metcalfe (Member # 5739) on 05-15-2013, 02:27 PM:

I can take some pictures of the intermittent shoe housing on our jjs if you'd like

Posted by Steve Guttag (Member # 268) on 05-15-2013, 04:20 PM:

You don't need "special" tools to set that screw with the ball/spring.

Posted by Jim Henk (Member # 3628) on 05-17-2013, 08:03 PM:

Good news. Took the head in, and the techs removed the intermittent to get a better look, then (gently) pried the shoe assembly from the intermittent with a flathead screwdriver in the gap. Corrosion, and years of never being pulled in/out. A gentle milling to smooth the shaft surface, and it's right as rain. No ball though. Just the spring and screw. Still snaps in and snaps out nicely, though. Hmmm...

As Tony has pointed out to me before, I'm not the one to go prying or forcing anything on a projector. Was happy to point that at a professional.

Posted by Louis Bornwasser (Member # 3063) on 05-18-2013, 11:06 AM:

See, all that oil that normally leaks everywhere, has a function: it makes it easy to replace the pad assembly! Louis