8mm Forum: Framing Problem with Bell & Howell (Sankyo 700)

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Posted by Melvin England (Member # 5270) on August 20, 2016, 04:31 AM:

I have a couple of projectors that have reached their limit as far as the framing knob will turn and the picture is STILL not framed properly.They are a Bell and Howell DCR Filmosonic and a Sankyo 700 which are basically the same machine.
I have examined the mechanics to find if there is a screw to loosen somewhere to adjust the claw setting but cannot see anything obvious. I am loathed to take the piece apart coz if I do, I am pretty sure the projectors would never see a piece of film again!
It appears to me that the fundamental problem is the wearing of a hard piece of rubber/hard plastic that supports the claw arm on the rotating cylinder.As it wears,the claw falls thus leading to my problem.

Does anybody know if someone would have any spare "rubber/hard plastic" bits that I could purchase? Sorry, I don't know the technical name for it.

Incidentally, I have read other older threads on this site, but none seem to mention my specific problem.

I look forward to your responses.

.

Posted by Andrew Woodcock (Member # 3260) on August 20, 2016, 05:57 AM:

I don't believe Edwin Van Eck has got around to printing these parts yet for Sankyo machines.

Almost certainly it will be wear and without actually seeing your machine, I would predict there will be internal adjustment that can be made close to the pivot point of the claw to allow your frame to rise slightly.

You would have to assess if you feel there is sufficient adjustment left to counteract the wear.

It may be an idea to request these parts from Edwin. He began making 3D replicas of the nylon cam and follower due to demand on other models.

Posted by Maurizio Di Cintio (Member # 144) on August 20, 2016, 07:52 AM:

Whilst I agree with Andrew there might be room to counteract the wear action, it seems strange to me Melvin didn't mention severe jittery image as the prime symptom of wear on this specific line of machines. Indeed when the shutter cam (that's the name of the part) is worn out on the horizontal plane (the one which does the hardest job), the claw pin will no longer retract to disengage sprockets prior to a new frame-pushing cycle. At the beginning of wear this leads to a slight jitter as the pin struggles to disengage the sprockets but eventually is successful and a new frame can then be dragged. By and by wear becomes more severe, the pin will no longer be able to disengage, stability will become an issue and the loss of the lower loop will get consistent up to the point a film can't simply be watched. In the worst cases sprocket tear might result.

IMHO this is a problem of framing knob assembly registration: for some reason the range of shift allowed by the framing knob is no longer the desirable one. I think Melvin should try to loosen the locking nuts on the framing knob shaft, find the proper range of action and re-tighten the nuts.

If actual cam (or the plastic pin on the claw arm!!!!) wear has occurred, he could loosen the three grub (Allen) screws/bolts which keep the shutter/cam assembly attached to the main shaft, and reposition such assembly 1-2mm backwards. This will cure the problem for some time even though it should be noted, this will cause the ssembly to not work in the best possible conditions (the claw pin might engage the sprockets way too close to the outer edge of the film).

Finally it might be good to re-grease this spot (grease not oil).

Please, Melvin, let us know what you will find out. Best of luck

Posted by Andrew Woodcock (Member # 3260) on August 20, 2016, 09:02 AM:

Maurizio clearly knows this machine very well Melvin by virtue of ownership.
My advice was purely generic having never owned any Sankyo machine.

I'd definitely follow Maurizio's advice regarding the framing mechanism first. Then look towards cam and follower wear,if this proves fruitless.

Posted by Melvin England (Member # 5270) on August 21, 2016, 12:41 PM:

Maurizio and Andrew - Thank you for your help and advice on this. I am still fiddling about with the B&H 48 hours later.... probably due to the fact I don't quite have the right tools for the job more than anything.
I have removed the plastic piece to inspect it and,hopefully re-adjust it as I put it back,but it is a really fiddly job as the whole mechanism won't come off because the two bolts on the frame height adjustment knob that prevents the mechanism coming totally off the screw are rock solid. Otherwise the job could be done in 10 minutes. It is a bit like threading a needle in boxing gloves.

Maurizio - You mention about the fact I didn't remark on the jittery picture. It does happen on the Sankyo 700 (which I have not touched)but this Bell and Howell projected a perfectly steady picture.....with most of the top of the frame at the bottom of the picture and vice versa.

I'll keep you posted on progress.

.

Posted by Maurizio Di Cintio (Member # 144) on August 21, 2016, 12:53 PM:

Melvin, in this case I think you should insist on unlocking those two 'interlocked' nuts on the B&H. Use two small pliers and remove the outer nut while keeping locked the inner one simultaneously. Some unlocking spray might help. Keep us posted...

Posted by Melvin England (Member # 5270) on August 21, 2016, 12:55 PM:

I will try. Thanks

Posted by Melvin England (Member # 5270) on August 27, 2016, 04:01 AM:

Eventually, I did succeed in removing the two screws as mentioned....a story in itself which I won't go into now.
It was such a relief to have the whole unit in my hand an was able to do what I wanted, in a matter of minutes. Basically, I took the plastic cam,turned it 90 degrees and re fixed it to the claw arm,then reassembled it all. I must have put the plastic on the wrong way around as the claw would not come out enough to engage with the sprockets in the film gate.
So,I dismantled it,turned the plastic around (keeping it at 90 degrees from its original position as that added a little more lift to the claw arm)then reassembled it.
This time the result was what Maurizio expected in the first place.... the claw arm now doesn't disengage with the sprockets!
So now I am stumped. I will contact Mr.Van Eck to see if he ever made the replacement part. In the meantime, I ,luckily, have a 2nd identical machine which is running perfectly so,without touching anything mechanical, I will open the back of that one and see if I can compare the two to see if I have overlooked something.

In the meantime, thank you both,once again, for your support and help.

.

Posted by Randy Wheeler (Member # 2141) on May 09, 2017, 03:20 PM:

Anyone find a solution to this problem with the "hard piece of rubber/hard plastic that supports the claw arm on the rotating cylinder"? I have two projectors with this problem now. Someone else posted a pic showing the claw and plastic ball so here is that pic:

Posted by Andrew Woodcock (Member # 3260) on May 09, 2017, 03:30 PM:

This part you are referring to is known as the cam follower.
I still don't think for this machine, there are any 3D replicas in circulation yet.
As this appears to be a common wear item on the Sankyo machines (as well as many other makes and models), it might be an idea for owners to request these parts from Edwin.

It would appear, there would be plenty of takers as long as people are confident to do the work with the new parts.

Edwin does supply some followers already for some machines so these type of components are something that can be successfully printed seemingly, although I've yet to fit any of the spare parts that I have regarding printed cams and followers.

Once a machine can no longer be framed correctly, beyond its adjustment range which nearly all I've seen have, the only solution to the issue is to find or make like new parts again.
They simply become too worn to allow the claw to rise to its correct uppermost position, hence the image you see on screen will never be centralized.

You typically do get a fair amount of adjustment though near the fulcrum of the claw before new parts becomes the only solution.

Elmo machines are some of the most durable I've seen where these parts are concerned (all metal), Sankyo and Bauer are among some of the ones which wear relatively quickly if not kept well lubricated with the correct grease.

Nylon parts were selected for their low noise and noise cancelling qualities but at the trade off of needing far more attention over the years.

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