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Tamron Twin-Tele disassembly problems
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PostPosted: Fri Jan 25, 2019 6:17 pm    Post subject: Tamron Twin-Tele disassembly problems Reply with quote

I recently acquired, at a very reasonable price, a Tamron Twin-Tele f/4.5-7.7 (135/225mm), complete in it's case with mounts for M42 and Exacta, but unfortunately the lens focus is completely seized at infinity. I've removed the shrouds to expose the brass focussing "nut" on the aluminium 12-start helix, but just can't get it to budge.

I've soaked the assembly carefully but thoroughly with penetrating lubricant over several days with no effect. I'm obviously loathe to go at it with hammers and wrenches or other "instruments of destruction" for fear of damaging the threads, so would appreciate the benefit of anyone else's experience in freeing off assemblies like this.

The lens itself is attractively small for a 135mm and the 13-blade pre-set aperture holds promise for some interesting out-of-focus effects, but being able to focus it elsewhere than infinity without using extension tubes would be a bonus Wink

Thanks for any insights Smile


Last edited by kypfer on Fri Jan 25, 2019 6:37 pm; edited 1 time in total


PostPosted: Fri Jan 25, 2019 6:25 pm    Post subject: Reply with quote

I'm assuming that you've removed the glass from the focus mechanism that is seized up.

I've soaked focus mounts in acetone for a week, taking out every day and putting some pressure on the mechanism before it finally freed up. Simlar 5cm F1.5, J-3's, J-8's, etc. The old grease gets like glue.


PostPosted: Fri Jan 25, 2019 6:42 pm    Post subject: Reply with quote

fiftyonepointsix wrote:
I'm assuming that you've removed the glass from the focus mechanism that is seized up.

I've soaked focus mounts in acetone for a week, taking out every day and putting some pressure on the mechanism before it finally freed up. Simlar 5cm F1.5, J-3's, J-8's, etc. The old grease gets like glue.


I've not removed the glass yet, though I don't anticipate that to be a problem, I do have a lens wrench.

I also have most of a pint of acetone in the cupboard, so that'll be my next approach. I'll probably take the lens out with some extension tubes for a bit of a "play" before I totally disassemble it, just in case I have an accident.

Thanks Smile


PostPosted: Fri Jan 25, 2019 6:44 pm    Post subject: Reply with quote

"Penetrating lubricant" sounds suspiciously like WD40 which is for water displacement and lubrication not penetration. Neat wintergreen oil is a fantastic penetrating oil, the secret ingredient of commercial true penetrating oils like Marvel Mystery Oil or Liquid Wrench brands. Effective for corrosion too.

Apply heat and cold to expand and contract metal maybe free it. Heat gun, freezer.

A light tap on either end of the barrel parts may free a jam.

Acetone mentioned above should dissolve any solidified grease, etc..

Edit: remove the glass & diaphragm to prevent damage to those parts!


PostPosted: Mon Feb 18, 2019 7:44 pm    Post subject: Reply with quote

Many thanks for the recommendations.

Having removed the glass, the barrel has been soaked in acetone for several days, intermittently subjecting it to as much twisting I could apply. A third application of boiling water from the kettle (whilst wearing rubber gloves) finally got everything moving Smile

I'll now spend some time cleaning out the residue, before re-greasing and reassembling and taking it out to play Smile

Thanks again, one and all Smile


PostPosted: Tue Feb 19, 2019 4:48 am    Post subject: Reply with quote

Nice, I was about to recommend a wee bit of heat, grease normally softens up naturally with it. Was it easy to get the glass out? I have a Soligor badged version which needs cleaning, fortunately the focus is all functional.


PostPosted: Tue Feb 19, 2019 8:03 am    Post subject: Reply with quote

Alun Thomas wrote:
Nice, I was about to recommend a wee bit of heat, grease normally softens up naturally with it. Was it easy to get the glass out? I have a Soligor badged version which needs cleaning, fortunately the focus is all functional.


Initial applications of heat hadn't appeared to have any affect, so I soldiered on and prayed a bit to the big god ASA-ISO in the clouds Wink

The front lens just dropped out once the retaining collar was unscrewed. There's two little slots for a lens wrench on my Tamron, so no problem at all. Similarly the rear group just unscrewed with the wrench. I didn't remove the aperture mechanism, it seemed I had to remove the focus "nut" to enable that to happen so I set it wide open and worked carefully ... I seem to have succeeded Smile


PostPosted: Tue Feb 19, 2019 3:07 pm    Post subject: Reply with quote

It's a great lens and well worth saving.

I have boiled lenses in a pan on the stove before now to get old and solid grease out of a lens. Of course I remove all the glass first, but I have boiled at least one with the aperture blades in place. I usually follow a boiling with a session of simmering just below boiling with a strong mix of water soluble de greaser such as Jizer which doesn't attack paint, plastic or alluminium.

https://www.amazon.co.uk/Swarfega-Jizer-5-Litre/dp/B006CLFE98

I've never boiled newer lenses with plastic parts though, maybe that's not such a good idea?

( I also have a nice copy of this Twin Tele lens for sale )


PostPosted: Tue Feb 19, 2019 3:33 pm    Post subject: Reply with quote

Lloydy wrote:
It's a great lens and well worth saving.

I have boiled lenses in a pan on the stove before now to get old and solid grease out of a lens. Of course I remove all the glass first, but I have boiled at least one with the aperture blades in place. I usually follow a boiling with a session of simmering just below boiling with a strong mix of water soluble de greaser such as Jizer which doesn't attack paint, plastic or aluminium.

I've never boiled newer lenses with plastic parts though, maybe that's not such a good idea?


Ha ha !

I'm very familiar with Jizer, but thanks for the suggestion, someone else may benefit from it Smile

Here's a quick shot comparing the Tamron with some other 135mm f/4 solutions. The Tamron on the left, a Retina Tele-Xenon on a DKL-PK mount in the middle and a recently acquired ISCO Isconar - surprisingly different and the Tamron is half the weight of the Tele-Xenar!

I'll be taking them all out soon for a comparative session, the Xenar is going to be a hard act to follow!