Film-Tech Forum ARCHIVE: Simplex Shedding

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Posted by Michael Rourke (Member # 1142) on 04-17-2002, 03:25 PM:

Howdy, for a couple weeks now one of my Simplex 1014's is shedding the hell out of prints. I have the minimum of tension on the trap and intermittent shoes, I have inspected the intermittent sprocket, gate pad, and tension straps on the trap. They all seem to be fine, althouth a little worn there are no burrs or hooks.

What other points are there to check? I think I'll replace the straps and treat the print with Film Guard, see if that works.

Posted by Mike Williams (Member # 1140) on 04-17-2002, 03:32 PM:

This model has the removable gate right?

If it is the one I am talking about, check to see that the bottom part of the gate (the gate pad) is not bent slightly (could be from somebody dropping it while our of the projector or forcing it closed when not aligned properly). That causes an uneven tension on the film as it passes the intermittent.

I would suggest removing the gate to compare it to one from another projector. If the gate pad is not the same angle, you may have found the problem.

Posted by Brad Miller (Member # 2) on 04-17-2002, 03:45 PM:

Is this something that has just happened? If so and assuming this is the Simplex model there the intermittent shoe is part of the gate, I think Mike has already in all probability found the problem. Instead of comparing it to another machine, you will be able to see the angle better if you just get down on your knees and slowly close the gate. The shoe should be aligned with the curvature of the intermittent sprocket before full closure. Those things are easily bent.

Posted by Aaron Sisemore (Member # 145) on 04-17-2002, 03:46 PM:

Remove the front part of the gate and look just past the non-soundtrack side of the trap. There shouyld be a little Allen head cap screw there, it is used as the stop to limit how far the gate closes against the trap rails. If this screw gets backed in too far it will cause the gate to close WAY too far causing shedding from hell. It take some trial and error but bringing that screw out a little bit should cure the problem.

-Aaron

Posted by Randy Stankey (Member # 64) on 04-17-2002, 04:50 PM:

I agree with Aaron: I say it's the tension, too.

Depending on the model of machine there may be a couple of different ways to adjust the tension.

On the PR-1014, which you say you have, there is no stop screw.
You adjust the tension by winding/unwinding the spring that pushes the gate shut. (Somewhat of a pain in the ass... call your tech.)

On later models with turrets, like the PR-1040 or PR-1050 there is a stop screw. It's a simple matter to adjust the screw that sticks out of the trap. (Inboard side, bottom... Allen head screw.)
A lot of the time, what happens is that the locking nut that keeps the screw from moving after repeated "slamming" of the gate gets loose and allows the screw to move. Over time it gets pushed in little by little until is starts giving you trouble. It's an easy adjustment to make if you are careful. There really is no special procedure or prescribed distance. A lot of people use the 1/4" Allen wrench trick. (Trap the wrench between the studio guides and the body of the gate shoe then adjust the screw accordingly.)

Whatever you do just work slowly and deliberately. Make small adjustments and test it. When you get it right, go back and recheck then put it all back together. If you have any doubt call the tech.

Posted by Joe Grace (Member # 341) on 04-17-2002, 08:34 PM:

It could just be the print. Did it start to happen when you played a different print on that projector?

Joe

Posted by Pat Moore (Member # 380) on 04-17-2002, 10:36 PM:

Yo, Randy;

There should be a stop screw for Gate closure on the PR1014 as well. It's been done a couple different ways over the years -- some are allen cap screws into the Trap with the head of the screw towards the Gate; others are reversed. Some have a locknut, some used loktite. I think the old original XL with the straight Gate and Trap closed all the way, but any curved trap Simplex (like the PR1014) has a closure limit screw of some kind.

If the machine has run film for a long time and this is the first shedding problem like this, I would have to look at the print first, especially if it just started. The shedding -- or most of it -- should stop after a half-dozen runs or so, unless there is something else going on with the film contact parts. Lower tension should help.

As it is, we at Strong are aware of this happening with the newer film stocks, and have been looking at how to decrease or even eliminate it. It's a challenge because there has to be some abrasion to have a steady image on screen.

Pat

Posted by Randy Stankey (Member # 64) on 04-17-2002, 10:56 PM:

Yeah, you're right... OF COURSE you are!

The manual that I looked at is a conglomeration of all the pre-Millenium models. I just looked at the first diagram I saw.

It's just that there are several flavors of Simplex where the gate adjusts by one of the two methods... Not to mention the PR-1060 with the flip-up gate.

Whenever I see a projector shedding or "Making Snow" the trap closure is the first place I look, right after I make sure the sprockets and pad rollers/shoe are all OK.

Posted by Pat Moore (Member # 380) on 04-18-2002, 09:55 AM:

I look the same places, Randy. I usually find it in tension, more on the intermittent sprocket and pad than anywhere else.

Tension on that intermittent sprocket is very critical. You don't really want the pad clamped down tight on the sprocket as that just puts unwanted pressure on the intermittent itself.

Pat

Posted by Michael Rourke (Member # 1142) on 04-18-2002, 09:26 PM:

Aaron wins the Cupie doll, thanks Randy for the 1/4" allen trick.

One more thing, I could turn the screw with my fingers, shouldn't it be harder to adjust this stop screw so that this won't happen more often?

I thought it might just be the print, that's why I waited until another print went into that house. I only spend about 8 hours a week at the 4 plex fixing up the place, all my shifts are at the 7 plex 4 blocks away.

Thanks again Film-Techers you have been an invaluable resource.

Posted by Tim Sherman (Member # 569) on 04-19-2002, 01:55 AM:

From my experience and from what i have heard, If that set screw is set too far back and the gate is closing too far you will hear the intermittant ticking louder then normal. Or is this just something that happens on the XL (i have only worked with XL's and 35's)? Also if you back out that set screw too far you will never be able to get a steady picture no matter how tight the pressure straps are. So take your time in setting that stop screw, and make sure it is perfect.

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Posted by Randy Stankey (Member # 64) on 04-19-2002, 08:22 AM:

If memory serves, there is supposed to be a "jam nut" on that screw, isn't there?

Take the correct size nut to fit on that screw and tighten it against the faceplate that the screw is going into. It'll provide pressure to keep the screw from backing out again every time you close the trap.

If you can't get a nut right away, a drop of nail polish on the threads before you put the screw in will temporarily hold it in place until you can do it right. Just remember to clean all of that stuff off before you put everything back together the right way.
(Decidedly temporary solution, just to get you by. )