williamxp Posted August 8, 2012 Share Posted August 8, 2012 <p>I just got my 'NEW' 2nd-hand Grandagon today, which is being mounted on a Sinar board. Fair enough. So I screw the front cell off the shutter. Simple. And then, when I do the rear cell, I felt some resistance come and go about three times and then it stuck there. So I use more force to screw this thing off. And there the rear cell goes off without its screw ring!!!!<br /> <br /> The ring is STILL stuck on the shutte!!!<img title="Mad" src="http://www.largeformatphotography.info/forum/images/smilies/mad.png" alt="" border="0" /><br /> <a id="attachment78484" href="http://www.largeformatphotography.info/forum/attachment.php?attachmentid=78484&d=1344456983" rel="Lightbox_918638"><img title="Click image for larger version. Name: IMG_1582_S.jpg Views: 0 Size: 75.8 KB ID: 78484" src="http://www.largeformatphotography.info/forum/attachment.php?attachmentid=78484&d=1344456983&thumb=1" alt="Click image for larger version. Name: IMG_1582_S.jpg Views: 0 Size: 75.8 KB ID: 78484" border="0" /></a><br /> <br /> <a id="attachment78485" href="http://www.largeformatphotography.info/forum/attachment.php?attachmentid=78485&d=1344456986" rel="Lightbox_918638"><img title="Click image for larger version. Name: IMG_1588_S.jpg Views: 0 Size: 64.4 KB ID: 78485" src="http://www.largeformatphotography.info/forum/attachment.php?attachmentid=78485&d=1344456986&thumb=1" alt="Click image for larger version. Name: IMG_1588_S.jpg Views: 0 Size: 64.4 KB ID: 78485" border="0" /></a><br /> <br /> <br /> NOW NOW HOW COULD I GET THIS THING OFF!! AND MOUNT ON MY SPEED GRAPHIC!!?????<img title="EEK!" src="http://www.largeformatphotography.info/forum/images/smilies/eek.png" alt="" border="0" /><img title="EEK!" src="http://www.largeformatphotography.info/forum/images/smilies/eek.png" alt="" border="0" /><img title="EEK!" src="http://www.largeformatphotography.info/forum/images/smilies/eek.png" alt="" border="0" /><br /> <br /> I THOUGHT RODENSTOCK COULD DO BETTER THAN THIS!!!<br /> <br /> ANY COMMENTS WILL BE WELCOME. i AM NEW TO HERE AND NEW TO LF AS WELL. :P<br /> <br /> MANY THANKS<br /> YING</p> Link to comment Share on other sites More sharing options...
bob_salomon Posted August 8, 2012 Share Posted August 8, 2012 <p>The fastest way? Take it to a qualified camera repair shop.</p> Link to comment Share on other sites More sharing options...
thirteenthumbs Posted August 8, 2012 Share Posted August 8, 2012 <p>Being you are inexperienced with such mechanical assemblies there is little you can do.<br> 1. run the retainer ring back down snug the 2 or 3 turns it wants to go.<br />2. once snugged at the normal tightened end check the threads of the shutter for foreign debris and remove it if found.<br> 3. unscrew the ring until it starts to get tight then turn back toward tighten then back toward loosen.</p> <p>Forcing the ring off can strip the threads on the shutter or the ring or both. Follow Bob's advice if working it back and forth does not loosen it up.</p> Link to comment Share on other sites More sharing options...
michael_briggs2 Posted August 9, 2012 Share Posted August 9, 2012 <p>Did you have a spanner wrench to remove the retaining ring? If you aren't sure what to do, Bob's advice is probably best. Using too much force might damage the lens.</p> Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted August 9, 2012 Share Posted August 9, 2012 <i>"Using too much force might damage the lens."</i><br><br>Looks like it <i>has</i>. Link to comment Share on other sites More sharing options...
dhbebb Posted August 9, 2012 Share Posted August 9, 2012 <p>Don't see the problem. As it is, you seem to have unscrewed the rear lens group from the shutter, which you need to do anyhow before you can unscrew the shutter retaining ring. If this ring is tight, you will need a correct shutter wrench (flat metal tool with pairs of "ears" for different sized shutters) or else a fully adjustable slot ring wrench to remove this ring. You do not need to remove the front lens group from the shutter to remove the shutter from the panel. Note: The rear lens group and the retaining ring are not directly connected in any way except that they both screw onto the shutter body.<br /> PS: Shutter wrenches look like this:<br /> http://www.ebay.co.uk/sch/i.html?_trksid=p5197.m570.l1313&_nkw=lens+wrench&_sacat=0<br /> (disregard the filter wrenches!) <br> or this:<br> http://www.ebay.co.uk/sch/i.html?_nkw=shutter+wrench&_sacat=0&_odkw=lens+wrench&_osacat=0</p> Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted August 10, 2012 Share Posted August 10, 2012 A <i>"rear cell </i>[that came]<i> off without its screw ring"</i>, and you do not see a problem David?<br>Yes, you need to unscrew the rear cell to remove the lens from shutter and board. But not remove the screw thread from the rear cell. Link to comment Share on other sites More sharing options...
dhbebb Posted August 10, 2012 Share Posted August 10, 2012 <p><em>A "rear cell [that came] off without its screw ring", and you do not see a problem David?</em><br /><em>Yes, you need to unscrew the rear cell to remove the lens from shutter and board. But not remove the screw thread from the rear cell.</em><br> There seems to be a problem with terminology here - the rear lens cell does not have a screw ring, it has a screw thread machined into the cell housing. I thought the OP was expecting the shutter retaining ring to come off when he unscrewed the rear cell. If the OP has turned the rear cell counterclockwise with such force that he has caused the bottom of the cell housing with the screw thread to fracture (which would take very high force indeed), then he certainly has a problem. The services of a repairman are required to rebuild the elements of the rear lens cell into a new housing and extract the fractured part of the old housing from the rear of the shutter - the cost of this may well exceed the value of the lens, even assuming that a new rear cell housing is available as a spare at all and that the broken metal can be extracted from the shutter without damage to this.</p> Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted August 10, 2012 Share Posted August 10, 2012 It would help, Ying Tang, if you would post your images somewhere where we can see them, not locked away only visible to members of another Forum.<br>But i believe you have persuaded the seller to take the lens back. Brave of him. Link to comment Share on other sites More sharing options...
dhbebb Posted August 10, 2012 Share Posted August 10, 2012 <p><em>you have persuaded the seller to take the lens back. Brave of him.</em><br> But a reasonable solution. If the metal of the rear lens cell seized in its threads and then fractured with a moderate application of force, it must have been VERY corroded!</p> Link to comment Share on other sites More sharing options...
jim_landecker Posted August 11, 2012 Share Posted August 11, 2012 <p>"If the OP has turned the rear cell counterclockwise with such force that he has caused the bottom of the cell housing with the screw thread to fracture (which would take very high force indeed), then he certainly has a problem."</p> <p>Looking at the pictures, I don't think this is the problem. Nothing has fractured and it's likely not corrosion. The WA Rodenstock lenses have an intermediate ring between lens housing and shutter, and I think the problem is that Sinar sometimes puts thread locking compound on the threads when they mount lenses to DB boards. When the OP tried to unscrew the rear cell, the thread on lens housing side broke free first, leaving the intermediate ring stuck in the board.<br> <br> </p> Link to comment Share on other sites More sharing options...
dhbebb Posted August 11, 2012 Share Posted August 11, 2012 <p><em>Looking at the pictures, I don't think this is the problem. Nothing has fractured and it's likely not corrosion. The WA Rodenstock lenses have an intermediate ring between lens housing and shutter, and I think the problem is that Sinar sometimes puts thread locking compound on the threads when they mount lenses to DB boards. When the OP tried to unscrew the rear cell, the thread on lens housing side broke free first, leaving the intermediate ring stuck in the board.</em><br> Diagnosis has been made more difficult by the fact that you need to be registered with large format forum to view the pictures at enlarged size. Assuming the situation is as Jim describes it, which is certainly plausible, and assuming also the OP has not yet sent the lens back, then (as I suggested earlier) the problem is not so great and merely requires an extra ring to be removed before the lens will come off the panel. Presumably this ring is slotted and can be released with an appropriate wrench such as those to which I provided links.</p> Link to comment Share on other sites More sharing options...
jim_landecker Posted August 11, 2012 Share Posted August 11, 2012 <p>Unfortunately the ring is not slotted, as I don't think Rodenstock ever intended the lens to come apart this way. Attached is a photo of a Grandagon 90/6.8 rear cell showing an example of the separate ring.<img src="http://oneeighth.com/Grandagon%20Lens%20Cell/Grandagon-rear.jpg" alt="" /></p> Link to comment Share on other sites More sharing options...
dhbebb Posted August 12, 2012 Share Posted August 12, 2012 <p>Jim you have the advantage of actually owning a Rodenstock lens - I have many LF lenses but all Schneider or Nikon. Do you believe that it is the case that the rear adapter has unscrewed at the point I have marked on your picture (as you say, not intended by the manufacturer)? If so, and if the two parts of the adapter are normally secured with locking compound, it might be an idea to screw the adapter back together with a very light application of locking compound - once this has hardened, I think there is a good chance the whole thing would unscrew in the manner intended.</p><div></div> Link to comment Share on other sites More sharing options...
jim_landecker Posted August 12, 2012 Share Posted August 12, 2012 <p>Dave, that may be possible. It looks like the OP's lens splits at the point you have marked. It sounds like he was going to send it back, though, so we'll probably never know...</p> Link to comment Share on other sites More sharing options...
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