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Not knowing exactly what you mean by worn, I would also suggest checking the trap to make sure it is holding the plate correctly.

Remember in setting up apertures, the biggest part of the job is levelling the machine, centreing the image (and frame) for both Flat and Scope, and, if necessary, adjusting the masking to the proper limits.

I have never heard of an aperture plate wearing out- projectors that are only 20 years old are still young if cared for.

There may be sonething else wrong. On my Simplex XL, sometimes the plate won't lock in properly. You just have to make sure you've got it all the way in. Sometimes I have to wiggle it a bit. Make sure that little "pin" is all the way into its hole. Push the plate forward if you have to.

Aaron, you are talking about single format aperture plates, right? Which means you change lenses manually. The plate is a sort of "Z" shaped stamped brass plate with a black plastic (or bakelite-like) handle.

I am guessing that getting money from your management is tough. The right way to check apertures is to order a length of the SMPTE test film (35PA) and go by what it shows when projected. It comes in 50ft lengths, but sometimes equipment dealers will sell a short length (you would need about 10ft. or so.) Personally, I think it would be a very good investment, as it's good for several different uses. Maybe you could "sneak" a 10ft purchase in through petty cash? I have instruction sheets I can mail you showing how to use it, if you are interested. And you can order it from almost any equipment, so call several for a good price. Also, if you would rather not let that tech know what you are doing, don't use the place your company uses.

But if you are not allowed to spent that much, you might try this: Try to order Simplex part G-2306. This is an aperture plate that comes already filed out (it's actually punched) to the suggested 0.446" x 0.825" (flat) opening. You can use this as a *very* rough gauge to see if the image is centered and if there's any cropping. Remember, though, this is not the suggested procedure.

Also, you can see if a new plate is held firmly. If a new plate stays in place, you can try it on other projectors, proving to your tech that new plates are needed. If your tech is a pain, (again) maybe purchase it with petty cash from an out-of-state dealer.

Michael, you are talking about the turret model. If I remember, the motor pushes the aperture in for scope. When power to the motor is shut off, a spring slides it back to flat. So, if the plate drifts while in scope, it could be a motor problem; if flat- a spring problem. It can be fixed; I suspect someone simply doesn't want to spend the money.

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My thinking was not to actually use the plate for regular shows, but rather a cheap test to if the existing plate(s) are indeed worn, and see if there's excessive cropping. You are right, though, it probably won't be centered when installed.

(See Annex A.4 of standard SMPTE 55).

I would caution that many of the leaders in circulation are copies of copies of copies, so they should not be used as a critical test film. For that, buy some SMPTE Projector Alignment Film 35-PA (RP40). It's available from equipment dealers and service companies, or directly from the SMPTE:
http://www.smpte.org/testmat/index.html