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-   -   Mamiya RB67 back grinding (http://www.film-and-darkroom-user.org.uk/forum/showthread.php?t=13469)

loganmiley 20th October 2020 12:17 PM

Mamiya RB67 back grinding
 
My RB67's rotating back has started grinding and began being really tough to turn and I'm not really sure what to do.

I'll link a video of what's wrong below.

Any help would be most definitely welcome,

Thank you

https://www.youtube.com/watch?v=0j1T...nel=LoganMiley

Terry S 26th October 2020 12:43 PM

Quote:

Originally Posted by loganmiley (Post 136262)
My RB67's rotating back has started grinding and began being really tough to turn and I'm not really sure what to do.

Ooh, that did me me cringe as the surfaces scraped. :(

But I'm just posting this to bring it back into the list of questions, as it may have been overlooked, for I'm sure there must be a member or two who could advise on this matter???

Terry S

Richard Gould 26th October 2020 01:20 PM

That made me cringe, something's not right there, but hopefully some more knowledgeable members than me can help
Richard

MKCarberry 26th October 2020 02:22 PM

Simply an observation from someone who's been a mechanic for 35 years. I'd say it's either a foreign object(s) gotten into the mechanism or something in the mechanism is worn or loose to the point of interference in operation. Are you capable of disassembling it? If not it's off to the repairman for it.

Sorry that's all I have but I'd stop doing that as it's sounding pretty bad.

Mike O'Pray 26th October 2020 05:15 PM

I don't own one so can't help. This may seem a naive question but given the grinding noise when the back is turned is there no signs of where this grinding is happening?

It sounds for all the world as if two surfaces are grinding against one another.

Mike

Martin Aislabie 26th October 2020 05:40 PM

Quote:

Originally Posted by MKCarberry (Post 136339)
Simply an observation from someone who's been a mechanic for 35 years. I'd say it's either a foreign object(s) gotten into the mechanism or something in the mechanism is worn or loose to the point of interference in operation. Are you capable of disassembling it? If not it's off to the repairman for it.

Sorry that's all I have but I'd stop doing that as it's sounding pretty bad.

Completely agree - it sounds like metal to metal rubbing in the rotating mechanism.

On my RB67 ProSD, there is a shiny chrome lever underneath the camera just in front of the rotating back, which releases the rotating back from the camera body.

I would remove the film back prior to trying to remove the rotating back mechanism.

Hopefully, when you remove the rotating back you will find a foreign object and the resulting damage hasn't been too bad.

The only thing that looks delicate when I remove my rotating back is the felt light seal - so provided you remove ALL the swarf and other debris, you should be OK.

(hold the camera lens upwards when you remove the rotating back - so any debris falls out of the camera and not into the camera)

I have seen rotating backs for sale on ebay if you need to replace it - but looking inside, there is not too much to go wrong.

Good luck

Martin

loganmiley 3rd November 2020 12:14 PM

Quote:

Originally Posted by Martin Aislabie (Post 136350)
Completely agree - it sounds like metal to metal rubbing in the rotating mechanism.

On my RB67 ProSD, there is a shiny chrome lever underneath the camera just in front of the rotating back, which releases the rotating back from the camera body.

I would remove the film back prior to trying to remove the rotating back mechanism.

Hopefully, when you remove the rotating back you will find a foreign object and the resulting damage hasn't been too bad.

The only thing that looks delicate when I remove my rotating back is the felt light seal - so provided you remove ALL the swarf and other debris, you should be OK.

(hold the camera lens upwards when you remove the rotating back - so any debris falls out of the camera and not into the camera)

I have seen rotating backs for sale on ebay if you need to replace it - but looking inside, there is not too much to go wrong.

Good luck

Martin

Hey,
Thanks all for your replies, someone else recommended I use some silicone lubricant spray and the back now completely rotates fine. Some black gunk ended up being pushed out so I don't know if a previous owner might have possibly put it in some dirt or likewise.

But I appreciate the responses, thanks,
Logan

Martin Aislabie 3rd November 2020 05:39 PM

Glad you got it sorted out.

Sand and grit cause havoc in moving parts - so you always need to exercise caution when and where you put your camera down.

Silicone spray needs to be used with care.

It is fine until it is used on silicone foam or rubber - which then causes the foam and/or rubber to turn in to a sticky yucky mess.

Martin

loganmiley 6th November 2020 09:21 PM

Quote:

Originally Posted by Martin Aislabie (Post 136509)
Glad you got it sorted out.

Sand and grit cause havoc in moving parts - so you always need to exercise caution when and where you put your camera down.

Silicone spray needs to be used with care.

It is fine until it is used on silicone foam or rubber - which then causes the foam and/or rubber to turn in to a sticky yucky mess.

Martin

It's unfortunately how it came from Japan, with over a £100 import fee attached to it, it just wasn't worth sending it back for a refund as that money would very much have been lost.

All I did was take off the rotating portion of it, between the body and the film holder, and turned it about 45 degrees so I could see into the bit where it rotates. I sprayed some little bits in there and very quickly after wiping it down some black bits of gunk just fell out, so yeah not quite sure what happened there.

Just glad I didn't end up having to return it!

Martin Aislabie 7th November 2020 06:03 PM

Glad your RB has been returned to full health.

Hope you enjoy using it.

I like mine.

Martin


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