Quick room temperature lens separation

[PRJ]

I just soak in acetone. Works fine.

I use a pin to scratch a mark instead of a pencil. Just be careful not to chip an edge.

[RedGreenBlue]

Anyone have a recommendation for an appropriate ultrasonic cleaner?

There are a number of cleaners on the market. All I can say I bought mine new decades ago from a supplier of watch and clock maker tools. It is made by L & R which is still in business. It's had a lot of use with absolutely no issues. I don't recall the rated capacity but I can fill it to the very top with 1 liter of liquid. It looks like there have been some techie changes to the current models, including heating, and digital timing; my unit has neither. I don't think heating would be a useful feature for the way I use my cleaner.

It looks like many of the cleaners on the market today are much less expensive than mine was way back when. But given L&R quality I'm guessing they are still expensive. The advantage for me has been it's been failure free for decades! Way beyond the warranty period.

For infrequent use, I'd select on capacity, price and reviews. I wouldn't get a heated unit. The 1 liter size allows me to clean a large variety of camera parts and even some household items. I've never needed a larger unit.

Scott

[Peter De Smidt]

Thanks, Scott!

[jarl33]

I wouldn’t expect to see an alignment mark, either. There’s no reason for marking during alignment / assembly in the cases when the optician does align them, sets them and moves on. However, there is reason for inspection marks and tracking serial #’s on the elements prior to bonding. Consider also that zeroing wedge / optical misalignment in a doublet can involve bonding and *then* edge grinding. None of which requires edge marking of any kind depending on the practices of the individual shop.

I’m not speaking from second-hand knowledge, as you can probably guess. As I’m sure you know, in specialized fields there’s a difference between what is practiced and what is in the literature. Either take my recommendation or not, it’s no skin off my back!

Regards,
Jason

For what it's worth:
https://youtu.be/VfcroN5iwgM?t=588

[Nodda Duma]

For what it's worth:
https://youtu.be/VfcroN5iwgM?t=588

I’ve seen that one before... it’s a classic. Starts off with the centering...on a very similar machine to what I learned centering on. The amount of touch labor (and without hair covers or finger cots!) they had back then on their production lines makes me cringe. You couldn’t make them like that today for any reasonable type of cost....not even in China! But.. a prototyping shop would look like that.

[jarl33]

Yep... I couldn't believe it when I saw the amount of work involved
Then again, some of those (Argus) cameras were close to $1k of today and, from the video, worth every penny.

In any case: the perimeter grinding explains why the lens elements should be put back in one specific, ideal orientation: the mechanical center is not necessarily the optical center. With a 100 year old lens the tolerances may (or may not) be so lax that it probably doesn't matter that much, but the effect was noticeable enough for the lens makers to spend the extra time to align them.

[Drew Bedo]

For re-cementing old lens elements, check with Professional Camera Repair in Houston: http://www.professionalcamerarepair.com/