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01-02-2014, 04:26 PM - 1 Like   #1
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Tair 300A , refurb, got this far (pics), help..

I am trying to clean and relube my recently acquired Tair 3 300A. This is the later version of the Tair 3 without the photosniper focus - it has a normal style focus (and is structurally quite different I think).

So far:

1. Front end off. 3 grub screws (NB all these screws are engaging in indentations so almost complete unscrewing is needed), unscrew.

2. Tripod mount off: 3 grub screws to take off screw collar, remove collar and TM.

2a. The light baffle at the rear end might need a lens spanner, mine unscrewed out of the mount easily.

3. Sleeve covering helicoid is held in place by another 3 grub screws. Once these have been loosened the sleeve screws away from the mount exposing the helicoid.

Results in pic1.

Pic 2 shows the famous 19 blade iris (bit smudgy but OK, the stickiness is in the ring and connections not the blades).

Pic 4 is close up of mount end. Like other Russian lenses this is a T-mount fitting. Just take the inner sleeve out of your T-mount and the lens adapts to pentax K, Nikon, Canon etc.

Pic 3 is looking down the mount end.

Turns out the sticky focus is due to the felt on the sleeve, helicoid is smoooooth.

This post on manual focus lenses is a bit helpful but doesn't have pics any more. His description of how to proceed I think confuses a later poster who I suspect was trying to lever the helicoid guide rails. I think that in order to proceed I need to loosen the outer ring at the bottom of the tube. Anyone been this far or know different? Grateful for any contributions.

Last edited by marcusBMG; 01-03-2014 at 07:38 AM. Reason: #2a
10-29-2014, 10:27 AM   #2
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I know this reply is a bit late but it may be of some help.

It is a few years since I attacked one of these lenses and although I have forgotten most of the dismantling details I can assure you that you are on the right track. You do have to unscrew that outer ring that is buried deep within the tube.
The only way to do it is with the custom made spanner ( the drawings of the spanner that have appeared on other sites are all copies of my original drawing that I published on the manual focus forum years ago).

The spanner doesn't have to be as pretty as the diagrams suggest and the one I used wasn't much to look at but it did the job.
The good news is that I still have it and if you would like to email me your postal address I will post it to you.

02-02-2015, 07:19 AM   #3
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Hi there guys,

New to the forum.

I too bought a Tair-3A recently and it's shape is not the best. Has a very stiff focus ring not to mention the apperture ring. I need to really push hard to turn from f4.5 to about f8, after that it goes well.

So basically I need to completely service and re-grease the lens. Unfortunately, I'm not experienced in servicing lenses and there isn't that much information / tutorials on how to do it to this particular lens, so I'm trying to gather all the info I can before I venture into it.

@Ray-uk Would you happen to still have your tool or at least a photo of it so I can have a look ?

Thanks a lot in advance!

02-02-2015, 07:35 AM   #4
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Hi Zylkan. if you aren't experienced in servicing lenses then I would suggest you practice on a different one. The Tair is one of the most awkward lenses to work on and even many experienced repairers have given up on these.
I don't really have any information now as it was a few years ago when I last worked on one and my original photos have been lost.(see here)
I passed my spanner onto MarcusBMG (see posts above) so he may be able to give you some advice.

Good Luck ... (you're probably going to need it)

02-02-2015, 07:41 AM   #5
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My refurbishment of my tair 3A has been and is pending... now that I have Ray's tool I really must make a push. If your lens is similar to mine Zylkan the problem with the stiff focus is not actually the helicoid but the felt.
Watch this space...

The tool was made with a grinder from an old open ended spanner I'm sure you can do something similar.
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02-03-2015, 02:35 AM   #6
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Hello my friends,

Thank you both very much for your replies. I'll keep studying and see what I can do about the tool.

I don't doubt that the felt might be the main issue as others have reported as well but I have to do something about it either way. Right now it's almost impossible to focus without holding the lens with both hands.

In the meanwhile I'll probably practice on my Jupiter 37A.

Thank you again very much
09-07-2015, 06:54 AM   #7
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Hi guys!

Just to give a quick update. I was finally able to unscrew that infamous outer ring! I followed the footsteps of a russian guy who fortunately left a nice set of pics to illustrate:

So I got a pair of long tweezers (about 20cm long) and forced them open to the desired width. I protected the rear element and sprayed some WD40 to help loosening it and then attacked it. It got off easily.
Now I've been cleaning the old grease on one part of the helicoid but the other part seems more complicated to reach which sucks to be honest. Makes no sense to clean and grease only 50%...
Btw, I think I will ditch the said felt...

Afterwards I look forward to reach the aperture ring which feels quite stiff in the beginning around f6 or so. The blades themselves seem to be in good condition so I'm hoping I won't need to take those out.

I did manage to destroy one set screw from the the front part of the lens. C'mon... who would make something so tiny on a 1,6Kg lens?! OMG... And there's a second one that I'm not sure I'll be able to use so I don't really know how I will solve that.

ALSO, I think I have a big problem that maybe someone can give me a tip or two. I had a piece of tape ready to mark the position where the helicoid would separate but it didn't quite happen as I expected, meaning I will have to find a way to get the focusing right and it's making me quite nervous. Trial and error for that on this particular lens seems like a terrible nightmare...

Any help appreciated!
Thanks in advance guys
09-07-2015, 08:09 AM   #8
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Gotta watch out for those set screws - don't use too much force, if it seems too stiff then some acetone to loosen ? thread locker, localised warming to expand the metal. The problem with the tair is that the thread may not be the same as JIS on other (jap) lenses you might try to cannabilise for replacements... best suggestion is to go down to your local engineering shop and id the thread then make a new set screw from a short bolt. I've done that for a t-mount, using a 0.5mm dremel cutting wheel to make a serviceable slot in the end (but it was a larger set screw).


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300mm, dissassemble, focus, grub, helicoid, mount, pentax help, pic, relube, repair, screws, sleeve, t-mount, tair, tair 300a
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