Reluctant beauty rings

[lumens pixel]

I am quite frustrated since I am servicing some lenses and I am unable to open the beauty rings of a Minolta 85 2,0 and of a nFD 135 3,5.
I have used rubber cones and even drilled holes in the rings for spanner use to no avail.
Did you ever faced the problem and what would be the solution?

[RokkorDoctor]

Drilling holes should really be a last resort (although on a few rare occasions it was the only solution for me as well).

Re. the Minolta 85 2.0, I assume it is the MF Rokkor MDII / MDIII one? (not aware of an AF one). If so then you can try all day to unscrew that beauty ring to no avail; it isn't screwed in but forms an integral machined part of the front cover of the lens.

Turn the lens to the MFD, and three screws will become visible around the circumference of the front barrel. Undo those and the front cover with integral machined beauty ring will lift off

[RokkorDoctor]

Assuming one has (and has tried) proper lens spanners and a set of rubber removal tools, here are some general suggestions for removing stubborn beauty rings, based on personal experience (to some extent also applies to lens-retaining rings):

1) look for any tell-tale clues as to whether thread-lock had been used. This usually looks like a small (say 0.5 inch) stretch along the thread where some shiny lacquer-like substance has been applied. This will usually soften when a small amount of either acetone or alcohol is applied. Dab it on there with a q-tip. Don't flood the whole thread, in case the front lens is a balsam-cemented doublet. If you know the front element is not a doublet, then you can be (a little bit) more adventurous with the amount of solvent used. Leave the acetone/alcohol to work for a few minutes (re-applying acetone as it evaporates): thread-lock compound needs a little time to soften.

2) Hold your hand/fingers around the circumference of the filter thread for a little while. This will warm up the front of the lens barrel and make it expand a bit, which may help release the ring.

3) Rather than just attempting to unscrew it, try "walking" it out. This involves the use of a rubber friction tool. Assuming a right-hand (normal) thread, TURN the friction tool counter-clockwise, whilst simultaneously WIGGLING it around in a clockwise fashion. Harder to describe then to demonstrate . But imagine the beauty ring as a slightly smaller toothed gear stuck inside an internally toothed ring. The gear can't freely turn as it is just too large and some of the teeth are always engaged. But it has enough play to wiggle around inside the internally toothed ring allowing the teeth to become disengaged on one side only. Imagine now if you wiggle the gear around the centre in a clockwise fashion, the gear will actually slowly turn counter-clockwise. You are trying to achieve the same here with the beauty ring. Although there are no teeth, the (often aluminium-on-aluminium) contact surface friction behaves in the same manner as the "teeth" in a gear. Still confused? Look up "harmonic gear drive"; although that usually involves slight deformation of a gear, the principle is very similar.

4) Still stuck? This may mar the surface finish a little bit, but get a very fine-tipped flat screwdriver, place the blade in the corner between the beauty-ring and the filter-thread, and give it a (very light!) tap. Repeat at 90 degree or 120 degree spots around the circumference in a clockwise order. This may break the stiction, and applies forces similar to as described in 3).

[lumens pixel]

I will try that. I was afraid that these screws were the connection for some sorts of helicoid and I am still not mentality prepared to play with these.

I need to access to the back of the front element for some cleaning. Hope there is no doublet here.

[RokkorDoctor]

[lumens pixel]

Many thanks. It worked. I was afraid of a micro fungus. Probably more a kind of coating damage. Could not wipe it out even using lighter fluid, hydrogen peroxide or distilled water.

Anyway the lens is reassembled and ready for use.

[mareinke]

Acetone could melt plastic name ring (Minolta MD), heat it with a hair dryer or apply lighter fluid.

Marco

[RokkorDoctor]

[stevemark]

There's another problem - some manufacturers like Canon have snap-on beauty-rings which look as if they were screw-in type!

I have a nFD 1.2/50 L here with stuck aperture, and I never managed to take off the beauty ring (which is essential for servicing the aperture). Not sure if it is a "screw-in" type or a "snap-on" type ... neither unscrewing nor snapping it off did work up to now. And since the lens itself is an perfect like-new state I don't want to apply too much force ---

S

[Lloydy]

I have used a roll of electrical insulation tape that I unwind until it fits just inside the filter thread and use that just like the rubber tools that you can buy. I make sure the roll of tape is warm, and I prefer an old roll, so the glue is on the side of the roll. The glue grips well, I've used this with good results when the rubbers have failed.

[RokkorDoctor]