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Persistent Eyemo Q


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#1 Paul Bruening

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Posted 17 August 2009 - 08:48 PM

Okay, guys and gals. Here it is again. Can an Eyemo be converted to 2-perf? Sure, if you throw enough money at it, obviously. But, can it be done with only a few alterations or gear swaps? If not, what are the main boggles? What would overcome them?

See, I've got this pellicle viewfindered Angenieux zoom. Slow as it is, it would go well onto an Eyemo and solve a lot of issues. It's the 2-perf hurdle that I can't get a complete answer on.

So, I keep fishing for info.
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#2 Robert Hughes

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Posted 17 August 2009 - 09:08 PM

Hello, Paul. I'm not going to pull the front plate tonight to look, but I believe you'd need to have several parts replaced in order to accomplish 2-perf nirvana: At the very least, a new gate (of course), a pull-down advance cam located in the front plate assembly, and a regearing of the advance sprockets, which would be the biggest headache. I'd say no, it's not practical. Shooting it as 4-perf and adjusting in digital post is probably the better bet.

Okay, guys and gals. Here it is again. Can an Eyemo be converted to 2-perf? Sure, if you throw enough money at it, obviously. But, can it be done with only a few alterations or gear swaps? If not, what are the main boggles? What would overcome them?

See, I've got this pellicle viewfindered Angenieux zoom. Slow as it is, it would go well onto an Eyemo and solve a lot of issues. It's the 2-perf hurdle that I can't get a complete answer on.

So, I keep fishing for info.


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#3 Paul Bruening

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Posted 18 August 2009 - 01:20 PM

I've got a PDF file of the repair manual. But, I can't quite visualize it without actually seeing a camera. Could you run the works at 12 fps, change the gear set to the pull down mechanism with a 2:1 increase and then move the pull down cam's pin position towards the center to cause the claw to travel half as far up and down? Is that easier said than done?
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#4 John Sprung

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Posted 18 August 2009 - 01:27 PM

The eyemo pulldown has two moving parts. There's the shutter with the cam and eccentric pin, and the claw assembly. The pin drives the claw up and down, the cam rocks it into and out of the perfs. You'd have to move the pin to half its original distance from the shutter axis. A lot depends on whether the cam plate is hardened. If it is, that would require annealing and a new heat treat.

If you could move the pin, the pulldown would move two perfs at a time. Then you'd have to change the gear ratio between the pulldown and the sprockets, and drive the rest of the mechanism at half speed.

All in all, you'd be able to buy an Arri IIC-T for a bunch less money. But if you really want to dump $10K++ into an eyemo, ask Clairmont. They have an excellent machine shop, and modify a lot of their own eyemos as crash/fire cameras.




-- J.S.
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#5 Robert Houllahan

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Posted 18 August 2009 - 04:27 PM

The eyemo pulldown has two moving parts. There's the shutter with the cam and eccentric pin, and the claw assembly. The pin drives the claw up and down, the cam rocks it into and out of the perfs. You'd have to move the pin to half its original distance from the shutter axis. A lot depends on whether the cam plate is hardened. If it is, that would require annealing and a new heat treat.
-- J.S.



I rebuilt my Eyemo and installed a Nikon mount the cam plate (and claw I think) are Titanium, practicality not machineable. I think all Eyemo's were made this way I used a 'Front" from an instrumentation camera for the Nikon conversion. I think it's probably best to keep the near perfect Eyemo design as it is and modify a 2C or Mitchell for 2-perf. Use the Eyemo for tight spaces or body mount etc.

-Rob-
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#6 John Sprung

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Posted 18 August 2009 - 06:36 PM

The eyemo went into production in 1927, so it's very unlikely to contain titanium, which wasn't produced in commercial quantities until the 1950's. I've also seen rust on eyemo cams and claws. So, the most likely material would be case hardened steel. I've had some success with stuff that's only cased on one surface drilling thru from the non-hardened side, but in this case the issue would be how do you get the location accurate coming from the back?

All in all, an existing Arri IIC-T would be a better camera for a lot less money.





-- J.S.
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#7 Paul Bruening

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Posted 18 August 2009 - 11:02 PM

Some shops can skip the annealing/hardening steps by drilling with some kind of electrical... thingie/whatchamacallit. That's what Bruce "G'day" McNaughton did to move the rollers down on my Mitchell pressure plate's rails for my scan head. The holes are nearly perfectly shaped and perfectly positioned. What I can't anticipate is how to change the gear sets. Gears are almost over the counter on the web these days. I don't know if there will have to be an intermediate or if there are gears already cut that can do the change in ratio. I hate to assume defeat until it is beyond obviously a fool's pursuit.
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#8 John Sprung

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Posted 19 August 2009 - 12:32 PM

Maybe Bruce can move the pin for you. Even in the olden days when I was doing this, we had the Boston Gear catalog, and could order stock gears. But most of their stuff was on the large side for this. I don't remember the guts of the eyemo well enough to guess what the gearing problem might be. Perhaps you could open it up and post photos. But be damn careful of that spring if it's still there.





-- J.S.
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#9 Robert Hughes

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Posted 22 August 2009 - 01:17 PM

Fortunately the mainspring on the Eyemo is nowhere near the shutter assembly. You can pull the front assembly with shutter in about 5 minutes and review the workings - it's quite clever, simple and functional. It's possible you could make a new cam that would cause the pulldown to operate at twice speed (ie 24 pulldowns when camera is marked 12 fps). You would also need to replace the original 170 degree shutter with a bowtie shutter such as found on the old CP16's.
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#10 Simon Wyss

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Posted 23 August 2009 - 03:21 PM

The eyemo went into production in 1927

The Bell & Howell Eyemo camera was introduced in 1925. Announcement in the May issue of the SMPE Journal
Never mind
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#11 Paul Bruening

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Posted 24 August 2009 - 04:28 PM

With Eyemos going for $600+ on Fleabay, it's out of my reach anyway. How close is a Filmo, conceptually, to an Eyemo? If I could snag a $10 Filmo would it reveal enough of an Eyemo to let me make some decisions?
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#12 Robert Hughes

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Posted 24 August 2009 - 09:41 PM

Of course a Filmo is a 16mm camera. The shutter mechanisms are different enough, I'd guess that you wouldn't benefit. Besides, the $10 Filmos (like the -A and the -DA models) are too old - they have dual perf sprockets, and the older ones have a completely different speed governing device than the later models.
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#13 Patrick Neary

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Posted 24 August 2009 - 09:46 PM

Fortunately the mainspring on the Eyemo is nowhere near the shutter assembly. You can pull the front assembly with shutter in about 5 minutes and review the workings - it's quite clever, simple and functional. It's possible you could make a new cam that would cause the pulldown to operate at twice speed (ie 24 pulldowns when camera is marked 12 fps). You would also need to replace the original 170 degree shutter with a bowtie shutter such as found on the old CP16's.


Hi-

Like John Sprung pointed out, you wouldn't have to operate the cam at 2x speed or mess with a bowtie shutter, you just need to move the pin on the cam closer to center to shorten the pull down and increase the dwell. I also wonder if you might need to reshape the cam, it's been awhile now since I had mine in pieces.
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#14 John Sprung

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Posted 25 August 2009 - 03:40 PM

How close is a Filmo, conceptually, to an Eyemo?


The Filmo is very much the same design scaled down to 16mm. The shutter, cam, and claw assembly is identical except for the dimensions. I really don't remember the gear setup. But somewhere I have a loose filmo gate, shutter, and pulldown assembly. Somewhere else, I have an eyemo with a spare gate, shutter, and pulldown assembly.





-- J.S.
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#15 John Sprung

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Posted 26 August 2009 - 01:41 PM

I found a picture of the extra Eyemo front assembly:

P0000782.JPG


-- J.S.
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#16 Paul Bruening

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Posted 22 September 2009 - 06:17 PM

Any new ideas or discoveries?
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