RZ67 pro ii cocking question and focus gear

Discussion in 'Medium Format' started by stewart_thorp, Jul 13, 2013.

  1. Hi there,
    question to RZ67 pro ii users out there, can you verify that this is normal for camera;
    context: When cocking lever: Film advances fine, mirror is lowered, shutter is cocked, but I am suspicious about the gears etc, as the focus rail of the camera appears to be missing a tooth, it is periodically notchy and clunks through to next part of travel. (so I am suspicious of internal state of camera)
    When advancing film, the cocking lever gets all the way forward and then at last 10% of stroke, 'breaks free' i.e. there is what I would call normal resistance while advancing the film, then when the lever gets almost to the focus knob, it clicks free of film advance, and haphazardly pushes to end of travel.
    Not having used this camera before, (my GX680 does it for me) I would have thought that the movement would have been smooth and predictable, but as I am suspicious I think it is 'falling off the end' of a gear or something. Also there was one instance where the lever went forward again afterward and gave me a feeling that can only be described as 'a camera ripping through the holes on a 35mm film' (the first and closest thing that sprung to mind to compare it to)
    And;
    Can someone of knowledge please give me an accurate indication of whether or not it is feasible to sort out the gear on the focus knob. Without knowing my abilities this will be difficult, although I'd say that I am competent, but not a specialist (vague I know) maybe some instructions/diagram/service manual
    The rack on the underside of the bellows is fine, thats about all the info I can give.
    Thanks for your time
     
  2. search engine-google; search term-rz67 service manual=
    http://www.mamiyaleaf.com/assets/files/documentation/RZ67PROII_Instr.pdf
    the instruction manual if you need one and a RB67 service manual but no RZ service manual.
    Is the focus lock lever fully released?
    Now some general repair info
    Camera focusing is accomplished by the rack on the bottom of the front standard rail and a pinion gear made on a shaft that runs across the body with the focus knobs attached by pins. The only problems that can occur is the rail comes loose and does not seat properly into the pinion, the pinion or rail strips, the pinion bushings wear allowing play in the pinion, or the focus knob pin breaks and the knob slips on the pinion shaft. Lock levers usually apply pressure to the pinion shaft preventing it from turning or making it difficult to turn.
    Check for any up/down play in the focus rails with the rail fully extended, normal should be no more than .001 to .005 inch. The focus knobs should have less movement except for turning forward and backward.
    There should be a stop pin at the rear of the rail that prevents them from being run out too far. Apply a light coat of white lithium grease to the focus rail teeth then run the rail in and out several times.
    I suspect the body is due for a CLA.
     
  3. Thanks Charles,

    CLA would be great, but therein lies the problem, the last person I heard of in New Zealand that worked on these has retired... I don't want to send it overseas if I can avoid it.
    I can confirm that the cocking lever is working correctly, so now its time to investigate the focus gear. The shaft is true, the focus lock is disengaged, the stop pin is fine, the problem I think is the pinion gear, as it happens every 360deg on the focus wheel, and there is a definite interruption to the focus travel.
    My theory on what has happened is; sharp knock to front of camera/lens while bellows have been extended, causing one tooth to not be a tooth.
     
  4. The RZ Pro II, and Pro IId models have a 'fine focusing' knob, adjunct to the primary focusing knob (rt-side).
    These 'fine focusing' knobs are to be used sparingly at best and moved slowly/finitely when used, otherwise,
    the gears will strip on the fine focusing drive...but the primary focusing gears usually survive this malady.
    From your post, I'm unclear if you are describing a problem with both focusing knobs...or just the fine focusing knob(?).
    Marc
     
  5. Well I'm in direct, distant view of runway 28L at SFO so there is a little bit of water between us.
    I can post a picture of a pinion shaft tomorrow. The pinion has a helical gear pattern. If it has been damaged then removing one focus knob, they may be attached with a set screw in the knob tightened against a flat on the shaft, the shaft should slide out of the body. A thin shim .010-.015 inch (washer) on the shaft next to the remaining knob should offset the defective section enough for the pinion to work properly. A lot depends on how the focus knobs attach to the shaft and how close to the end of the shaft they attach. The damaged gear tooth may be repairable with solder or brass brazing.
    The majority of the mechanical parts should be accessible by removing the bottom of the camera. If the bottom is easy to remove then the pivot shafts can be oiled with a pin oilier ( sample: http://www.amazon.com/PIN-POINT-PRECISION-OILER-WITH/dp/B000Y8BDHM ) and gears can be wiped with grease. The key is to leave only a trace or a light sheen. Too much oil or grease can cause problems or cause parts to stick.
    Isopropyl Alcohol or electrical contact cleaner are safe degreasers to use on cameras. Naphtha in its many forms (lighter fluid), lacquer thinner, and similar chemicals are not safe for camera repair as they remove special coatings, damage rubber and plastic, or may dissolve sealants or bonding agents used in the camera.
     
  6. Just to give a little feedback from the other side, I've used lighter fluid to clean shutters for decades, and much stronger chemicals if that didn't work. You do have to be certain that there are no fiber or plastic parts in the shutter, but in old shutters, it's usually an all metal sort of deal. It can take many days to a week to evaporate out, but I have normally used the cameras right away w/ no ill effects. Whatever coatings the manufacturer may have put on any parts inside are usually related to the aperture blades, and those coatings are going to be long gone in most old shutters. What you want is things to be squeaky clean. Grit or a sticky residue are the culprits in shutters, unless you have a mechanical issue like an aperture blade that came loose or a broken part in there.
    Therein lies the rub, as you have no idea what people have used on the shutters over the years. I've seen shutters that were seemingly lubed w/ Vaseline, car motor oil, WD40, even cooking oil. That stuff can be very difficult to get off the parts, so you will need to use something strong to get the job done. Most shutters run perfectly fine dry too, so there is no need to go putting oil into there unless it's a specific, light watch oil, and even then it should be used in tiny amounts and wiped off so that only a miniscule residue remains. I prefer dry 99.9% of the time. My experience relates to old shutters, like the Compur and Vario types you would see on an old folder. More modern shutters are different, and like Charles said, you really want to understand what is in there before you start squirting fluids on or in things. But on old stuff, do what you need to do to get it clean is usually good advice. Anything I might recommend is something that has worked for me in multiple instances, over the course of many years. It's based on real experience, not simply my opinion.
     
  7. Marc, just to confirm it is a problem with both coarse and fine focus, at the same point in the rotation of the knobs. So as rotate it clockwise, the coarse and fine work as they should (but feels grainy) then when the bellows are extended about 15mm it hits it's first 'notch' and at that point both the coarse and fine stop working and decouple from the bellows, although it must only be one tooth if this is the case, as when I keep turning it, it re-engages no problem, although this happens to be at the point that you want to focus on a subject - so back and forwards trying to get best focus on one side of the notch as the bellows gently jump at each side of the stunted travel. Then at 360deg or evenly spaced along the travel of the bellows the same thing happens.
    Charles, that would be great if you could post a pic of your pinion shaft (!) Offsetting via shim - That's a great idea, i understand in concept without having seen how it works. And with regards to repairing the part itself, I thought that this particular part in the pro ii was plastic not metal? I guess I will find out. I definitely use iso, I like the fact that it evaporates without residue! And it's taken a while but I am gradually grasping the 'less is more' with lubing. Still a little stubborn in that area.... SFO = San Fran? Great city, just recently saw Ken Block tearing it up woah that guy does his thing well.
     
  8. SFO = San Fran?​
    Yes the initial plume of smoke from Asiana 214 rose above the tree tops and highrise closest to me but I could not see what was causing it until I turned on the TV.
    The fine focus will be fine, standard gear teeth cut into the pinion shaft, a secondary coupling gear, and a larger outer gear on the inside of the fine focus knob. Gear ratios are such to cause little movement of the main pinion shaft with a larger movement of the fine focus knob. The pictured pinion is from a Century Graphic. The RZ pinion will be similar. The RB67 service manual,
    http://rb67.helluin.org/files/2010/02/Mamiya-RB67-Pro-S-Repair-Manual.pdf , shows the focus pinion to have standard gears on both the rack and pinion with screws to adjust the backlash. The focus pinion is on pdf page 27. Its been many years since I had a RB apart and the RZ will be a similar build.
    And, yes, you have a damaged tooth position on the pinion shaft.
    00bpOA-541364484.jpg
     
  9. Wow!! Still the safest way to travel tho huh? I can only image the situation before, during and after the incident, what a major!
    Thanks for the photo, very helpful, I will carefully and tentatively attempt to locate, access, remove and possibly repair the part. Still, just because I have the tools, I am still very wary of being incompetent.
    I recently ruined a perfectly good helical focus mount for an Agfa Varioscop 60 105mm lens - I was so proud of cutting an M41 thread into it to fit my Nikon El-Nikkor to it, but discovered it had play and was sticky, old grease etc. So rather than flushing it externally and adding lubrication (which would have increased the play no doubt) I attempted to disassemble it, and the detent ball has slipped into the outer ring somehow internally and it is on my desk in pieces, stuck like a stuck thing. Anyway, my LPLVC7700 I feel is a far superior enlarger, I just wanted to see how sharp I could get images with a condenser - I had a point source light source and everything tee'd up for it....
    Thanks again, and the link to manual is VERY helpful ta
     
  10. Its 4 1/2 nautical miles from my house to that end of the runway. Can't see the runway for the haze and a 5 story new construction a mile away.
    The focus knobs may be attached with nuts under the end covers. The covers may snap onto the knobs or they may be attached with adhesive. In either case a 1.4mm or smaller slot Jewelers screwdriver under the edge of the knob center cover will be needed to pry it off. If you take the bottom off be careful you don't break any wires as they can be very difficult to reconnect.
    Detent balls can be devils. A small dab of grease on their socket helps hold them in place during assembly. I have as much trouble with their backup springs as I do with the balls. I avoid disassembling lens with internal helical focusing.
     
  11. and a single gear track rack and pinion from a 2x3 Graflex RB Series B.
    00bpQG-541367984.JPG
     
  12. Thanks again Charles for your descriptions and links, will carefully and methodically dissect my RZ!
     
  13. Charles, success! very enjoyable actually pulling the covers off the RZ and having a wee look. Turns out is was a plastic part, and it was missing some teeth, but the upshot is that i was able to remove it, as it was only the little side gear for the fine focus knob. The main focus gear is brass, and now it operates smoothly through the whole travel! Now the fine focus knob turns freely without effect, but I never really used it anyway.
    Is great having the right tools/screwdrivers/pin wrench set etc
    The inside is vastly different to what you posted, but same concept.
    So now 100% happy with the unit.
     
  14. Congratulations on finding the problem and a fix. Yes, camera mechanics have changed in design over the last 40 to 60 years but remain basically the same.
    You might be able to find a repair shop that has a replacement gear or try your hand at making one.
     
  15. MAC group (Mamiya America Corp.) is pretty good about supplying parts. I expect you could order the part (gear) from them if need be.
    If you need the service manual for the RZ67, they could probably supply that too. Or, I can post the PDFs of that if you have need of them.
    -Ed
     
  16. Hi Ed, I have located some parts from MAC, they have updated the gear for fine focus to metal, thats a bonus! If you could supply a service manual that would be great thanks - I know enough to install these parts, but would like some info on checking for film plane focus. Thanks
     
  17. Hi there,
    Ive also the problem of the fine focus gear worn away, as i found out when took the bottom plate and focus covers off.. only problem i have now is i cannot get the strap connection off the side, so i can take the plastic side panel off to remove the worn fine focus gear..
    Have yas any tips as to remove this please? also could anyone help me with a service manual? as i would like to try and service my rz since its taken apart at the moment
    Thanks for your help!
    Steve
     
  18. The strap lug is probably sealed with some form of thread locker. I don't know what will loosen it. Heat from a soldering iron, butane torch, acetone, some other solvent?
     

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