Probably dumb question

[Rossf]

Hello peeps-I’ve noticed some objectives have had their thread greased (and hence RMS hole in nose) and others not-should objective threads be greased at all?
Regards ross

[BramHuntingNematodes]

I think the smallest film of anti seize could be useful. I have had some objectives locked up pretty tight before and did not like it.

[PeteM]

Good news is that brass on brass is relatively resistant to galling. Since most objectives and most of the better nosepieces will have brass threads, you shouldn't need it.

I've occasionally seen a very tight fit on the threads going in - possibly use a tiny bit of anti-seize there. However, if it runs or outgasses you're operating pretty near the rear lens of that objective.

You'll see the opposite sometimes in objectives meant for classroom use - a bit of Loctite to keep them both in adjustment and from walking out of the classroom.

[MicroBob]

Hi Ross,
since this is not a thread that transmits power or moves a lot no real lubrication is necessary. The material don't tend to attatch to another under normal conditions. A fine smear of sewing machine oil can't harm though. I do have a few microscope objectives and never had the impression that one of them was lubricated intentionally

Bob

[Rossf]

Thanks for the replies guys-some of mine have quite a lot of old oil and want to clean them up and see if they need it-been fixing an x/y stage and find no matter how careful oil and grease gets transferred to places you don’t want-so want to get rid of any unnecessary oil/grease anywhere to prevent the dreaded oil finger print on optics-some objectives have back element very close to start of thread.
Regards ross

[Rossf]

PeteM I like your comment about locktight to, stop naughty ADD kids from pinching objectives! Must be a science teachers nightmare...

[hans]

PeteM I like your comment about locktight to, stop naughty ADD kids from pinching objectives! Must be a science teachers nightmare...

Yeah, probably explains why I was unable to remove the objectives from my Reichert 150. Had not considered that someone might have intentionally glued them in place.

[wabutter]

The Series 160 and 150 objectives were torqued into the nosepiece using an objective wrench to prevent students from stealing or damaging the objective. They were not glued in nor was locktight used. I wish I still had my tools with the wrench so I could provide a picture. The wrench is fairly simple to make.

[PeteM]

I've found connector pliers handy for removing stubborn objectives. One of several types linked below.

Super stuck ones get gripped in a 5c collet, with a tiny bit of heat (the female part - tiny hot air pencil) and penetrating oil (Kroil) judiciously applied.

https://www.amazon.com/Crescent-52910N- ... 049&sr=8-4

[BramHuntingNematodes]

The rubber strap wrench is also a good thing to try--a good general purpose microscope tool as well

[hans]

Thanks for the suggestions. I had not tried anything too extreme yet. Seems like it takes quite a bite to cause actual optical damage. I have a Reichert 10X Neoplan that looks like someone used a pipe wrench on it, but no optical defects I can see compared to my other 10X Neoplan.

The Series 160 and 150 objectives were torqued into the nosepiece using an objective wrench to prevent students from stealing or damaging the objective. They were not glued in nor was locktight used. I wish I still had my tools with the wrench so I could provide a picture. The wrench is fairly simple to make.

Good to know, do you remember where/how the wrench gripped the objective?

[Greg Howald]

Grease is never a good idea with optics. My lab can get pretty hot during the day if I'm not home. Grease gets lose when you warm it up and this is can get, well, greasy. Threads are brass. Brass is its own lubricant.
I just wouldn't do that. I bought a used scope on eBay once. Someone put grease on the condenser. Took me all day to clean up the mess.
Good luck. Greg

[BramHuntingNematodes]

There absolutely should be grease on some parts of a microscope. I think perhaps some people used to packing bearings might over apply, but several racks come out of the factory greased and even on my ancient scopes original factory grease can be found here and there.

Objective threads probably don't need grease. When I think of self lubricating metals I usually think of bronze rather than brass, but brass threads kept in reasonably dry, clean conditions shouldn't present a problem. On the there hand, it's hard to say exactly what the composition of metals used is if you're going to be mixing objectives. I have had some experience, most memorably a wild 20x phase objective, that by way of corrosion had glued itself into my old B&L and it was not great. No telling how long it had been in there, it wasn't a great match in that stand. Anyway, sparing and thin applications of anti seize might not be the worst idea, and I have never had a similar problem again after the faintest application of some on some of my objectives.