Film-Tech Forum ARCHIVE: On Simplex 1050, what's the likely culprit for waxy dust on the intermittent sprocket

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Posted by Justin Hamaker (Member # 2165) on 07-15-2008, 03:40 AM:

On one of my Simplex 1050s, I'm getting a waxy dust on the intermittent sprocket. It's not a lot, just enough to notice after a full day. But I don't know what the most likely culprit is, although I do realize it has something to do with the contact between the film and the film gate, film trap, and/or intermittent sprocket and/or intermittent shoe.

I've tried playing around with the screw to adjust how far the film gate closes, but I don't really know what the proper setting should be. The knob for the tension bands is set at 1.

With this projector, I've had problems in the past with the intermittent shoe assembly falling off so the last time I added a drop of Loctite to the screw.

I've also had problems in the past with the film gate closing too far causing the pivot to overextend. As I said above, I have played with the adjustment screw, but I don't really know where to set it beyond judging how much tension is on the film when I advance it by manually turning the motor.

Posted by Monte L Fullmer (Member # 2797) on 07-15-2008, 04:56 AM:

With the gate closed, the face of each shoe, over the "I"- sprocket, should have complete contact with the sprocket without the shoe tension spring showing any movement. Too tight can cause this dusting problems that your mentioning.

It's a trick to do when adjusting that Stop Allen Screw being mounted on the back side of the trap.

Keep your tension setting at "1" for least wear.

Some prints shed this dust and some dont, but if it's a continual problem, I'd check the bands and the curved gate rails for unusual, or excessive wear and even any sprocket with worn teeth that can actually shave the insides of the sprocketholes to create dust matters.