Isolette III rangefinder has me f-f-frustrated!

zhuologist

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I'm cleaning up the rangefinder of my newly-acquired Agfa Isolette III. All was going well until it came to freeing up the focussing knob which is well and truly stuck.
Despite following the excellent advice offered by Sandeha Lynch and Roland & Caroline et al, I've made no progress. I removed the rangefinder in order to dip the stuck end in naptha, allowing it to soak for 48 hours, but it remains stuck. If I grip the focussing knob with pliers and apply considerable effort the knob will just about move, although it may just be slipping on the inner brass core it surrounds. As the accompanying pics show, this has resulted in scratches and burring to the knob itself.
Any fresh ideas are warmly welcomed - along with any offers to purchase a replacement rangefinder(?)
 
Sorry, I forgot to include pics!
 

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This may sound outright silly but .. uh.. have you tried removing the two flathead screws that stick out of it?
Edit: Correction, three.
 
Hi TenEleven,
Thanks for your prompt reply. Yes, I removed the two flatheads, but these just allow the focussing knob to spin around helplessly. They do allow for the easy removal of the knob, which will be handy when I get around to de-burring it. With the knob removed, I applied a strong grip to the now exposed inner brass core, but it still refused to budge. I also removed the third, outer screw but this is just a stop limit screw.
Regards,
Nick B.
 
When I was trying to unfreeze my Isolete III, I didn't have any success using common solvents including naptha, acetone, penetrating oil and xylene.

So based on a tip I read from Chris Sherlock, I sprayed some CRC Lectra Clean into a small glass jar, and allowed the rangefinder assembly to soak, periodically swirling the liquid about to bring fresh solvent in contact with the grease. When flakes of fossilized green lubricant stopped accumulating on the bottom of the container after a number of days, the parts still seemed frozen. But with a bit of persuasion (not as extreme as what you've already applied!) I got the mechanisms moving again. There was still a lot of polymerized old lubricant fouling the works, but it was soft, crumbly and easily removed.

I'd suggest wearing gloves and working in a well-ventilated area, as Lectra Clean is a strong degreaser, and I find the smell nauseating. I'm away from home at the moment and can't check the exact Lectra Clean variant used, but IIRC the active ingredient was perchloroethylene aka dry cleaning fluid.
 
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I went through this last year, and it took a while to unfreeze the same screw and the pivot for the mirror.
Electric contact cleaner is great, but PB Blaster is awesome
I apply it with the tip of a toothpick or a wire hook, let it seep in, apply etc etc

With AGFA grease you have to be patient, it can almost be a torture to free those mechanisms
 
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PS you might want to remove the outer wheel (it has 3 grub screws) and work the brass inner wheel only

 
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I agree with titrisol. go easy. agfa grease turns into green adhesive. just go easy and be persistent withe the solvents. I unfroze one and put a new bellows on it. It takes fine pix.
 
When I was trying to unfreeze my Isolete III, I didn't have any success using common solvents including naptha, acetone, penetrating oil and xylene.

So based on a tip I read from Chris Sherlock, I sprayed some CRC Lectra Clean into a small glass jar, and allowed the rangefinder assembly to soak, periodically swirling the liquid about to bring fresh solvent in contact with the grease. When flakes of fossilized green lubricant stopped accumulating on the bottom of the container after a number of days, the parts still seemed frozen. But with a bit of persuasion (not as extreme as what you've already applied!) I got the mechanisms moving again. There was still a lot of polymerized old lubricant fouling the works, but it was soft, crumbly and easily removed.

I'd suggest wearing gloves and working in a well-ventilated area, as Lectra Clean is a strong degreaser, and I find the smell nauseating. I'm away from
I went through this last year, and it took a while to unfreeze the same screw and the pivot for the mirror.
Electric contact cleaner is great, but PB Blaster is awesome
I apply it with the tip of a toothpick or a wire hook, let it seep in, apply etc etc

With AGFA grease you have to be patient, it can almost be a torture to free those mechanisms
Hi Jeff,
Thanks for the advice. I'm going to give PB Blaster a go - it seems to be the least expensive route to take. JeffS7444 has recommended CRC Lectra Clean, which sounds like a good alternative, and has Chris Sherlock's seal of approval, but it's mighty expensive. I will share my results with fellow green grease sufferers in another post!
 
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When I was trying to unfreeze my Isolete III, I didn't have any success using common solvents including naptha, acetone, penetrating oil and xylene.

So based on a tip I read from Chris Sherlock, I sprayed some CRC Lectra Clean into a small glass jar, and allowed the rangefinder assembly to soak, periodically swirling the liquid about to bring fresh solvent in contact with the grease. When flakes of fossilized green lubricant stopped accumulating on the bottom of the container after a number of days, the parts still seemed frozen. But with a bit of persuasion (not as extreme as what you've already applied!) I got the mechanisms moving again. There was still a lot of polymerized old lubricant fouling the works, but it was soft, crumbly and easily removed.

I'd suggest wearing gloves and working in a well-ventilated area, as Lectra Clean is a strong degreaser, and I find the smell nauseating. I'm away from home at the moment and can't check the exact Lectra Clean variant used, but IIRC the active ingredient was perchloroethylene aka dry cleaning Jefffluid.
Hi Jeff,
Thanks for the heads up. I like the sound of CRC Lectra Clean, and Chris Sherlock's seal of approval, but not the price, unless there is a cheaper, generic alternative. PB Blaster, suggested by titrisol, looks like the least expensive option at around £18 - I'll give that a try and report back.
Regards, Nick B.
 
I went through this last year, and it took a while to unfreeze the same screw and the pivot for the mirror.
Electric contact cleaner is great, but PB Blaster is awesome
I apply it with the tip of a toothpick or a wire hook, let it seep in, apply etc etc

With AGFA grease you have to be patient, it can almost be a torture to free those mechanisms
Hi titrisol,
Really like the sound of PB Blaster. It seems to be around £18 on Ebay, and if it works will be money well spent. I'll give it a try and post the result. Thanks for the suggestion.
Nick B.
 
18 quid? wow! that is expensive!
Inthe US is cheap ($8 last time); electrical contact cleaner should be available in the UK under a different brand (Kroil I think)
Electrical cleaner it is also cheap and must be used by all electricians in the UK... I found this one for less
 
Hi titrisol,
Thanks for your suggestion. I like the sound of PB Blaster. It seems to be about £18 on Ebay, and if it does the trick will be money well spent. I'll give it a try and post the result.
Regards, Nick B.
Have you fixed AGFAS before?
Patience is the additive you need the most
 
18 quid? wow! that is expensive!
Inthe US is cheap ($8 last time); electrical contact cleaner should be available in the UK under a different brand (Kroil I think)
Electrical cleaner it is also cheap and must be used by all electricians in the UK... I found this one for less
Have you seen the price of Kroil?! £23 at least. I'll try the PB Blaster first and report back
 
PS you might want to remove the outer wheel (it has 3 grub screws) and work the brass inner wheel only

Yes, I tried that but the inner brass wheel is smooth and difficult to grip tightly enough. The milling on the outer wheel provided more grip, unfortunately not enough to prevent the burring seen in the pics.
Nick B.
 
Hi Jeff,
Thanks for the heads up. I like the sound of CRC Lectra Clean, and Chris Sherlock's seal of approval, but not the price, unless there is a cheaper, generic alternative. PB Blaster, suggested by titrisol, looks like the least expensive option at around £18 - I'll give that a try and report back.
Regards, Nick B.
No offense taken: I'm sure there's more than one way to solve this! I can't comment on PB Blaster, because I am not familiar with it.
 
I agree with titrisol. go easy. agfa grease turns into green adhesive. just go easy and be persistent withe the solvents. I unfroze one and put a new bellows on it. It takes fine pix.
Thanks bigeye. Yes, patience and persistence seem to be the prerequisites with these Agfas. Luckily the bellows on mine are light-tight so no attention needed there. The Apotar lens is stuck fast, but I'm replacing it with a Solinar from a scrap Isolette and hope for great things from it.
Regards, Nick B.
 
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