What grease to use on zoom drive gears?

Question

I've had to tear down my Canon A490 pretty much to individual pieces, in order to get a whole load of sand out of the works. In the process, I've probably washed off most of the grease that was in the zoom drive gearbox. (I didn't put it there; I bought the camera new and now when I opened it up there was grease - and sand.)

My instinct would be to leave plastic gears unlubricated, but the first stage is a worm on the motor's shaft driving a helix gear, and I guess that makes for a lot more sliding friction than in the subsequent stages - all spur-to-spur. Indeed, most of the grease seems to have been (and some still is) on the worm, but it's inevitably worked its way through the transmission as the gears have meshed.

I don't think any of the gears are oriented such that their turning could fling blobs of grease onto the lenses, but some clever IRC people have suggested I should look for a lubricant that won't condense on the optics. I also know that not all lubricants are compatible with plastic - I guess they could corrode / dissolve certain materials?

So, clever people of Photography, what lubricant should I put on that worm? There's obviously a cost involved in adding grease - it captures any grit that does make it in there. But Canon obviously decided that the worm should be greased, so I want to just go along with that.

Answer 1

Well I'm no expert on lens diassembly or grease for that matter, but I am one heck of a Googler. Anyways I found quite a few references to using regular lithium grease. But I believe the most comprehensive information that I found in my 5mins of searching was the following tidbit from the "personal view" forum:

I wanted a PAO based oil with a sticky property that had PTFE(teflon). I found Super Lube 51004. It's a high viscosity PAO based oil with PTFE. a few small dabs of oil on the helicals and the lenses move smoothly and easily with no "whispering" that you get with metal/metal contact. Just don't use too much, a small amount is all that is needed.

But then again on that same webpage(link is above), someone who seemed every experienced noted that almost every lens they have disassembled had lithium grease in it. So that might just be your ticket.

Answer 2

Don't know if this works for you but when I serviced a old lens from ebay (CZJ 135 f/4) I used dielectric/silicone grease since. I used it since I could easily get one from a hardware store.

Testing it out after application, the focus ring was smooth and had no issues.

Answer 3

I called a few local camera repair places, and while it's difficult to separate anecdotal "Oh just use [blah]" from actual knowledgeable advice, the consensus (read: two of them agree) is to use ceramic grease - the specific product mentioned is Tamiya Cera-Grease, apparently a boron nitride-based lubricant (obviously the soft graphite-like allotrope, not the hard diamond-like one!).