My second 16mm projector, a B & H 624 has a little problem with the focus. The projector's slight vibration seems to make the focus slide just a bit out of focus. Ever 4-5 minutes I find myself make small adjustments to the focus. That has never happened to me for the Elmo 16CL or my Eumig 810 D. Have any of you experienced that, and do you have any suggestions? Not sure what kind of anti-lubrication I should use to the mecahnism.

Wonder if that is a common problem. One of the Norwegian club members had this problem also

It sounds Elvind that you might need a new bit of rubber tubing on the focus screw, I have never been successful in removing the plate
to rectify this. What I did use to alleviate the problem was to use elastic string, the kind they use in folders for magazines or even
in the packing of chickens, its usually wrapped around the legs etc. Anyway, a few twists of this between the screw and lens housing
and you'll find your lens holds focus, just wrap it around and tie it off, no more slippage.

Not entirely sure what kind of elastic string you mean although I think I might understand. Have to try this. Thanks!

Hi Elvind, it's the elasticated string used in files for holding magazines like FFTC etc, it is common enough, it comes in various colours,
when you buy a chicken, chances are elastic string will be wrapped around the wings and legs to hold them in situ. Even this will do the
job, it just keeps your lens screw in position, and if you wanted to remove it, a sharp blade will do this, but as an emergency stop gap,
I've used it on both of my Bell & Howells to no ill effect, but sharp focus.

I have never seen elastic strings on a chicken. Maybe we don't have this in Norway. My English is not good enough to understand strings used in files for magazines. Maybe Vidar or some other Norwegian understand and can explain to me. But I get the concept of a thin elastic string. I will look for something like this. Thanks again!

Have no fear Elvind, I'm sending a film to Vidar so he can record his, I'll put some in with it and Vidar could pass it onto you, if he'd
be so kind. I know with the plate on the side, I couldn't remove it to put new tubing on, so went for the next option, and it works a treat.
So don't panic my friend, help is on the way.

Cool, thanks! I'll see Vidar at the next club meeting!

The string arrived today. Thanks so much Hugh! And thanks to Vidar for forwarding it to me! We have a great bunch of people here in the forum!

I will test it later tonight.

I hope that you can fix the problem Elvind. Let us know how it all works out.

He might have the string from Hugh to fix it now. Do let us know

It was no room for the string between the screen and the focus house. I thought it was, but then the screw didn't want to go round anymore. I tied all different places, but with no luck. To better see what was going on I removed a plate covering the screw mechanism. I tried to put the string there too, but with no luck. There just wasn't any room. But then I realized that those same screws could make the plate covering the screen could be fastened such that it made a pressure on the screw. I did that, and now it works! I should have realized this in the first place!

But thanks again, Hugh! I really appreciate all your help for a friend far away! :-)

Hi Elvind, my B&Hs had the same problem you're suffering now, I couldn't remove the access plate to the lens screw, as what happens
is the rubber deteriorates over time. It is a simple job to replace, but you need special tools to remove the plate, therefore other means
had to be found, I discovered that putting this string between the plastic screw and the lens housing makes the screw harder to turn, all
you're doing is increasing friction and therefore your focus should hold. Ill put some pictures up later to show what I mean. The access to
do the same job on the Fumeo 8mm is by two slot head screws, on B&H a safe cracker is needed.

Here we are Elvind, a picky is worth a thousand words....

Aha! That explains a lot. Mine doesn't look like this, and now I understand why this worked for you. I will make some pictures tonight (at work now). Thanks!

This is how my projector looks like:

I would think Elvind, if you remove that slot head screw and lift that metal plate, there will be the focusing screw and a piece of soft plastic or rubber tubing should solve your problem.

I removed that plate and expected it to only be a cover and not the mechanisme to hold the screw in place. And my plan was to put something between for pressure like you said. But when I took a closer look I saw that the plate itself made pressure to the screw on each end of it. I could actually tighten the screws with a screwdriver a bit harder, and then it behaved like it should! I think I have solved the problem! I watch the whole "Lifecycle of the insects, part 1" and it was kept in focus the whole film! Thanks again for all input and help!

I start to really like this machine. My Elmo 16CL is much easier and it will still be my main machine, but this old machine is much cooler. I have this at home, and my 16CL at the cabin where most of my films are.

I have only one issue left now as I have a power cord (bought from Phil) and the focus is ok: The machine has a still image function. You can stop the film and it is supposed to put a piece of dark glass between the light source and the film. But it doesn't work. The film proceeds as normal with full light, but just with an additional "bzzzzt" sound. But this function is off course not important at all. Maybe I figure it out one day.

If the wormgear have been replaced,it can have been substituted with one without the still function. As you say, you can live without this function. I Believe it was good for educational purposes.

If I remember, the old B&Hs I used to have had this type of arrangement Elvind, I think its just the rubber that will be old.

I will open it and take a look.

I'll have a gander at the old models Elvind, to see if there's any similarity.

Hi Elvind, checked out the B&Hs, they are the same set up as yours, I thought there might be a rubber insert, but it is just a ribbed
rod that engages with ribs on lens housing, adjustment of two screws in plate governs pressure on lens and focus, which I understand you've done.