Thread lubricant?

[juan]

I just acquired a 100-year old Rapid Rectilinear triple convertible lens, and I'm a bit concerned about screwing the various elements in and out to convert the lens. The barrel is made of brass - a somewhat soft metal.

I know the dangers of getting oil, etc. on the lens glass, but I'm wondering if some of the more modern lubricants might be good for the threads and not migrate to the glass itself. Any ideas?
juan

[HenceForthWith]

I just acquired a 100-year old Rapid Rectilinear triple convertible lens, and I'm a bit concerned about screwing the various elements in and out to convert the lens. The barrel is made of brass - a somewhat soft metal.

I know the dangers of getting oil, etc. on the lens glass, but I'm wondering if some of the more modern lubricants might be good for the threads and not migrate to the glass itself. Any ideas?
juan

Do the threads bind? If not, I would probably avoid it. I would just take extra care threading and unthreading. However, you could try some dry graphite powder, applied sparingly to the threads, rubbed in, and wiped off. If that doesn't work, I can give you some info on greases made specifically for inside lenses.

[rbarker]

Thread lubricant? A mention of digital will usually get the thread moving quickly.

While you might want to clean the threads with a bit of alcohol or naptha applied to a cloth that will compress into the threads when you wipe them down, I wouldn't actually lubricate external threads on the lens components. Lubricants tend to attract dirt and grime, which over time would do far more harm to the threads than normal brass-to-brass wear.

[John Kasaian]

How about teflon tape??

[John Koehrer]

Juan,
Use canning wax, rub the male thread lightly against the block of wax. It takes very little doesn't spread & leaves no noticable residue.

[jimgalli]

I have dozens of these and haven't worried about this so far.

[Dave Parker]

I have never felt the need to lubricate the threads on my lenses, even my convertables.

Dave

[Deckled Edge]

... you could try some dry graphite powder...

Graphite is a powder and will always remain a powder. It is very stable and will find its way into places you don't want powder, such as between elements, onto film, etc. I have been very successful keeping graphite away from any of my lenses. On the other hand, there is a stable lubricant which stays put and is very readily obtained, and that is Lubriplate. It is used on automobile engines during assembly, comes in a tube with a small spout, and LITTLE dab will do ya. I used it on gear rails and gears, but have only used it once on a lens--the flange for my Wide Field Ektar was a little out of round, and it helped screw the lens down completely.
Like Shaggy, I have used paraffin or even soap with good results.

[wfwhitaker]

I just acquired a 100-year old Rapid Rectilinear triple convertible lens, and I'm a bit concerned about screwing the various elements in and out to convert the lens. The barrel is made of brass - a somewhat soft metal.
...

Brass threads? No lubricant. You're not going to wear the threads in any measurable sense simply by interchanging the elements. Keep it clean. Cleanliness is next to godliness and resale value.

[jd callow]

Cleanliness is next to godliness and resale value.

For the former that may be true, which is good to know because according to Nietzsche faith ain't going to get it:

A casual stroll through the lunatic asylum shows that faith does not prove anything.

HenceForthWith that is a great signiture!

As for the question I agree with a few of the others: get it clean, keep it cleanand carefully remove any burs. Teflon tape would be good if you wish to seal the air inside, but probably would not otherwise be helpful.