Polaroid mp-4 shutter speed

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damiafix
Posts: 9
Joined: Fri Oct 27, 2017 1:39 pm

Polaroid mp-4 shutter speed

Post by damiafix »

Hi to everyone,

I am looking for a guide or a schematic to disassemble a Polaroid mp4 shutter speed. After a basic cleaning, I have to reassemble it and it seems to be a quite complex mechanism.

Image

Any suggestion would be extremely appreciated.

All the best!
D.

Charles Krebs
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Location: Issaquah, WA USA
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Post by Charles Krebs »

Looks like a Copal #1 press shutter. Polaroid used "press" type shutters from both Prontor and Copal. This looks lake a Copal to me.

I think it would easier to find the information you want on a "Copal Press" rather than under the Polaroid name. (I have no idea if the inside mechanisms would be exactly the same even if Copal made these under contract for Polaroid).

You might want to contact SK Grimes and see if they could offer some info. They are (or at least were at one time) big on repairing shutters like this.

damiafix
Posts: 9
Joined: Fri Oct 27, 2017 1:39 pm

Post by damiafix »

Hi Charles,

thank you so much for replying. Regarding the Copal Press No.1 shutter speed, I did a research on the web but I did not find any photography of the inner mechanism so I can't do any detailed comparison.
To be honest, exteriorly they seem similar and I don't exclude that the 'engine' is the same.

I would be really happy to get a confirmation, just to understand if I have a double possibility to find some useful information to disassemble my Polaroid shutter speed.

Image

Anyway, it follows a photograph, which I found on the web, of the inner mechanism of the Polaroid Mp-4 shutter speed. A picture which shows how to reassemble the blades of the iris would be extremely helpful.

Image


I will try to contact SK Grimes too, even though I think that they will not be so happy to share documents which they use to repair shutter speeds for their own business. But who knows...there's no harm in trying!

Any additional contribution or advice is more than appreciated.

Best. D.

Choronzon
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Joined: Sun Feb 21, 2010 9:14 am
Location: Chicago USA

Post by Choronzon »

What symptoms are you trying to repair? These are simple mechanisms.
I am not young enough to know everything.

damiafix
Posts: 9
Joined: Fri Oct 27, 2017 1:39 pm

Post by damiafix »

Choronzon wrote:What symptoms are you trying to repair? These are simple mechanisms.
Hi Choronzon,

thank you so much for your kind interest.

The first problem is that it doesn't work properly at the speed of 2 and 1. Especially at 1, it is slower than the effective speed.

The other one is related to the blades of the iris which, now, have to be reassembled.

Many thanks.

Best. D.

Choronzon
Posts: 384
Joined: Sun Feb 21, 2010 9:14 am
Location: Chicago USA

Post by Choronzon »

The top mechanism in your photo is the slow speed escapement with tiny gears. It removes as a unit with 2 small flatblade screws on either side. Soak it in acetone while actuating it's lever and then blow dry. If that doesn't restore the speeds, it may be too worn. I wouldn't oil it as oil spreads.
Regarding the blades, clean them in acetone and reinstall them with the shutter open as on the T setting. This is the default when the speed plate is off as in your photo. They only go in one way, and there are usually smaller pre-blades that install under each large one.
Good luck, you'll be learning a trade.
I am not young enough to know everything.

damiafix
Posts: 9
Joined: Fri Oct 27, 2017 1:39 pm

Post by damiafix »

Choronzon,

thank you so much, you are really kind. Regarding the speed problem, I will be carefully following your leading lines. As far as the latter, I don't have any schematic to reinstall the blades in place. Any suggestion?

I found the following photograph which is from a Copal 0 shutter speed.
Image

I can clearly see how to place the blades since they are really similar to the ones of my MP-4. Unfortunately, I can't see the position of the small pre-blades. You wrote that I have to place those pre-blades under each large one. That is clear, but in my case there are just 3 pre-blades. What do you think about?
Image


It follows a photograph of the shutter speed's side on which the blades should be installed.
Image

I don't have acetone but I own isopropyl alcohol and ethyl ether. I suppose the latter is preferable. I apologize for so many questions but I am relatively new in this.

All the best. D.

ChrisR
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Post by ChrisR »

I've used liquid lighter fuel a few times for ungumming things. It has worked well for me, and for us is much easier to get.
I believe it's similar to what can be called "naphtha" - fairly imprecise hydrocarbon not far from gasoline/petroleum.
Chris R

damiafix
Posts: 9
Joined: Fri Oct 27, 2017 1:39 pm

Post by damiafix »

ChrisR wrote:I've used liquid lighter fuel a few times for ungumming things. It has worked well for me, and for us is much easier to get.
I believe it's similar to what can be called "naphtha" - fairly imprecise hydrocarbon not far from gasoline/petroleum.
Hi Chris,

thank you so much for this. I will evaluate it. I was just trying to understand if I can use something which I have at home or if it is better to buy other solvents for the cleaning.

Best. D.

Choronzon
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Joined: Sun Feb 21, 2010 9:14 am
Location: Chicago USA

Post by Choronzon »

Open the shutter mechanism by cocking and then releasing. The shutter is now in the open position at the Time setting. Install the blades in such an order that the blades are not blocking the aperture, but lay around just to the outside. Don't close the shutter while doing this or the blades will jump out at you. Place the 3 pre blades under the first 3 leaves. Put the shutter cover back on and screw it down. Now you can close the release
I am not young enough to know everything.

pierre
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Joined: Mon Jan 04, 2010 12:37 pm
Location: France, Var, Toulon

Polaroid mp-4 shutter speed

Post by pierre »

Dear,

I have an mp-4 shutter fully functional sleeping.

It can be exchanged using MP.
Regards

Pierre

damiafix
Posts: 9
Joined: Fri Oct 27, 2017 1:39 pm

Post by damiafix »

Choronzon wrote:Open the shutter mechanism by cocking and then releasing. The shutter is now in the open position at the Time setting. Install the blades in such an order that the blades are not blocking the aperture, but lay around just to the outside. Don't close the shutter while doing this or the blades will jump out at you. Place the 3 pre blades under the first 3 leaves. Put the shutter cover back on and screw it down. Now you can close the release
Dear Choronzon,

thank you so much. I didn't have time to try yet. As soon as possible I will follow your guide in order to install the blades. I will let you know the result, obviously.

Thank you once again.
Best. D.

damiafix
Posts: 9
Joined: Fri Oct 27, 2017 1:39 pm

Post by damiafix »

Dear Choronzon,

thanks to your guiding lines I have been able to efficiently clean the mechanism and to reinstall the blades. The mechanism is perfect now an the speed is correct, even though...there is something which is not clear to me.

I know that sometimes "less is more" :D but...I can't figure why, at the end of the operation, I have the following result:

Image

I installed the blades counterclockwise, starting from the n.1, under which I put the first pre-blade, and so on. As you can see there is an extra blade.

Any suggestion would be extremely appreciated.

Best.D.

Choronzon
Posts: 384
Joined: Sun Feb 21, 2010 9:14 am
Location: Chicago USA

Post by Choronzon »

Are you sure the shutter is in the open "time" position when you're installing the blades? The extra one just goes on top of the last one installed for spacing thickness
I am not young enough to know everything.

Choronzon
Posts: 384
Joined: Sun Feb 21, 2010 9:14 am
Location: Chicago USA

Post by Choronzon »

Are you sure the shutter is in the open "time" position when you're installing the blades? The extra one just goes on top of the last one installed for spacing thickness
I am not young enough to know everything.

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