Film-Tech Forum ARCHIVE: Adjusting Tension on Century Take-Up

This is topic Adjusting Tension on Century Take-Up in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Hillary Charles (Member # 769) on 04-27-2017, 05:42 PM:

Hello guys, one of our Century take-ups lost tension, and before we attempt to adjust it, I figured it best to get your input on the process. How do we determine optimal tension? Is there a particular procedure? Anything we should look for regarding wear? Thanks in advance!

Posted by Jack Ondracek (Member # 1466) on 04-27-2017, 06:12 PM:

I'm sure pretty much everyone will chime in on this one.

To start with though... I've never seen a V-belt be used as a take-up. Guess you've made it work, though I can imagine a reason or two why it might not be ideal.

That said, where is the slippage coming from? Is the belt so loose it's sliding on the pulleys, or is it the felt-pad "clutch"... or maybe both? Looks like you've got the spring backed way off there.

Posted by Monte L Fullmer (Member # 2797) on 04-27-2017, 06:29 PM:

I used a system where I put the full reel down in the magazine and tape the end down.

Turn on the motor and give the reel a flip backwards. Should take two seconds to reverse the direction.

Actual method was to use a fish scale and measure the pull weight on the scale with the film attached to the hook on the fish scale with motor running.

Luckily, you have 2k magazines, for the tension is higher for 6k reels.

True, the spring is back out almost all the way, usually meaning that the felt pad is dried out increasing the friction between the pressure disk and the shaft disk.

We used to oil the felt pad so adjustments can be made more accurate.

Ive seen V belts for take ups since finding the leather round belts are getting harder to find. Sometimes, the clutch is so tight that the belt itself is rotating the pulley and not let the clutch assembly do the task.

For a Century with that small hold back sprocket, too much tension will cause the film to "sing" across the sprocket teeth and wear the teeth down.

-Monte

Posted by Hillary Charles (Member # 769) on 04-27-2017, 07:01 PM:

Thanks for the quick feedback, guys! The setup is exactly how we got it out of the theater. When we tested everything out, it worked okay, so there was no need to adjust anything. Until now! [Wink]

Posted by Gordon McLeod (Member # 33) on 04-28-2017, 07:07 PM:

Check the leather slip disk in the clutch and ensure it is dry and oil free

Posted by Dave Macaulay (Member # 813) on 05-04-2017, 09:44 PM:

We always adjusted the takeups so that when starting with film threaded onto an empty house reel, tighten a bit past where it would NOT get any slack (which of course would soon pull tight and break acetate, or with estar jump teeth on the holdback sprocket and tighten up the soundhead loop as well as damage the leader).

Posted by Hillary Charles (Member # 769) on 05-09-2017, 09:39 AM:

We had a chance to check it out again, and the belt is tight. It takes a bit of pushing on the spindle to get the clutch to slip. In comparing it to the other take-up, the spring in question does not have the same degree of tension. There is about 1/4" more thread showing beyond the "tightening knob" (for lack of the proper term).

We'll throw on the reel of junk trailers and feel more confident about what we're doing, thanks to your great advice, guys! [thumbsup]