Filing a projector gate

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carllooper
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Filing a projector gate

Post by carllooper » Thu Jan 15, 2015 5:06 am

In order to do transfers of Super8 shot on the new Logmar I have to file the gate on the projector I use for transfers (if I want that extra image area the Logmar exposes).

Does anyone have any suggestions on what to look out for when filing a gate?

I'm concerned that in filing the gate I'll be introducing the potential for abrasions (scratches in the film). Are there any tricks to learn. And does the filed part require any resurfacing with anything?

Otherwise I'm considering getting a new gate machined (from a CAD design I'm considering working up). But sounds a lot easier to just file an existing gate.

Carl
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David M. Leugers
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Re: Filing a projector gate

Post by David M. Leugers » Thu Jan 15, 2015 8:06 am

Careful filing with a diamond file is not that big a problem if you make sure to leave no burrs and to do scratch tests with some virgin exposed and developed film. Scratches and abrasions show up easier on clear leader.

Machining the gate is another option and preferred to my way of thinking.

Mmechanic
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Re: Filing a projector gate

Post by Mmechanic » Thu Jan 15, 2015 10:26 am

Since I’m a trained professional mechanic I can tell you that such work actually is not filing but grinding.

Often the aperture plates are hardened steel, so with a file (mostly hardened tool steel) you won’t get far.
Square oil stones or ceramic stones are the choice. Always work against the front surface (touched by the film).

Patience helps.

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MovieStuff
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Re: Filing a projector gate

Post by MovieStuff » Thu Jan 15, 2015 4:53 pm

Gates on projectors are usually cheap metal that is molded rather than machined and then covered in a plating of some kind. Filing will initially seem difficult until you get past the hard chrome plating then it suddenly goes very quickly, so be careful. Whether you file the existing gate or have it machined, you will need to do clean up using a Dremel polishing tip, which is a rubber eraser looking piece that is impregnated with aluminum oxide. One trick to get Into the corners of the gate is to hold the spinning polishing tip against sandpaper to create a point.

Roger

carllooper
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Re: Filing a projector gate

Post by carllooper » Thu Jan 15, 2015 11:23 pm

Many thanks David, Simon, and Roger.

Very much appreciate your feedback.

The plate isn't that hard. I guess it's because it's just a cheap Super8 projector. I tested a corner of the plate, and was able to grind into it fairly easily using an ordinary file. And yes, it was tough at first but gave way.

C
Carl Looper
http://artistfilmworkshop.org/

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