8mm Forum: Projector Take Up question

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Posted by Chip Gelmini (Member # 44) on June 28, 2008, 12:36 PM:

Recently, I was asked if there was an easier way to build my Towers without the need of old 35mm projector take up motors and clutches.

The answer I believe would be to use a 16mm projector as the take up machine.

However, in theory of course, and based on the principle that 16mm is twice the size as super 8, therefore runs at twice or nearly twice the footage per minute (super 8 @ 21 fpm; 16mm @ 45 fpm; and 35mm @ 90 fpm) the 16mm machine must be set at 18 frames per second while the super 8 machine would be set at 24 fps at the sound rate. This avoids the 16mm machine pulling too hard on the super 8 drive train.

16mm machines require two things to do this

1. Obviously the speed control factor described above.
2. Brass adapters by Neumade for stepping up to super 8 on the 16mm shafts, along with the finger clips to hold the reels on, that are found on the Eiki machines similar to the Elmo super 8 projector shafts.

3. And finally making it clear that all Bell and Howell classic school machines will NOT be good for this because the shafts do not have the finger clips!

If you're with me this far, how many of you agree this would be possible?

Chip

Posted by Fabrizio Mosca (Member # 142) on June 28, 2008, 02:43 PM:

I tried something similar using a fumeo 16mm, that allows regulating tension on the take up spool, and some adesive tape for locking the reels on the shafts.
Problems with my set-up was that the film may jam on the 16mm projector to the lack of 8mm rollers.

Later I found that in Italy ther was someone that built a flat base with two arms for 750mt super8 reels (one of these arms was motorized) that was suitable for almost every projector. Unfortunately there was no chance to regulate the friction on the reels, but up to 500mt reels there was no problem during projection.

Posted by John Whittle (Member # 22) on June 29, 2008, 09:08 AM:

Have you considered going with old reel motors from a 1/4 inch tape recorder? The motors usually could be controlled with some means in the tape recorder for high speed and regular speed and you could back tension the feed reel.

Take the motors and associated circuity and remount on a flat piece of metal and find a couple of reel shafts from a donor Super8 machine and drill and tap and then attach them with set screws on the motor shafts.

You'd have the advantage of setting the motors to "on" before starting the projector so the film would be wound without bounce on the start up.

I thought about this once for a 16mm machine (much like Eiki does on the XP4000 Xenon) but never got around to trying to fit motors in. If you've got an old reel to reel machine that has direct drive (and there were lots in the "high end audio" scale) or find one at a yard sale, it might be a good project.

John

Posted by Rick Skowronek (Member # 385) on July 02, 2008, 05:25 PM:

I agree with John Whittle. Coming from a background of audio, specifically tape recorders, thes reel-to-reel units almost to the one used standard AC induction motors for both the take-up and rewind systems. How they accomplished the reduced torque on the take-up during normal play, and even more reduced for back tension on the supply reel, was almost always accomplished, in the higher end general class consumer units, by putting a substantial wattage wirewound resistor in series with the motor. If any of you have these units, pop the back off and you'll probably notice these resistors mounted near the motors.

While not electronically classy, it worked and worked well. You will probably have to fool with the value hence it would be smart to get a wirewound unit of a couple thousand ohms with a slider adjustment. Should probably be 10-20 watts depending on the motor.

Something I haven't tried but may be on the classy side would be a ceiling fan speed control. Cheap and almost infinitely adjustable. Whatever the case, don't use a regular incandescent dimmer as they are not geared for inductive (motor) loads at all. Might work really slick for adjusting take-up torque on virtually any regular inductive motor. Could kick up the speed control for rewind it if you need it.

Rick

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