Finally an upright-some advice please

[Rossf]

Been collecting bits over the last few months for an upright-finally found a very nice looking BH-1 originally from Wright state university for just over $160 USD-cosmetically it immaculate-focus great-stage X/Y movement great-nose a bit stiff but will deal with that later-two main probs-the condenser holder was so stiff-dismantled it and plastic gear and guide look ok-very gluey oil-will remove that and relube- do the plastic gears need oiling of some sort? What type if so? Also the field diaphragm wheel is very stiff-doesn’t feel like the actual aperture that’s stiff but the turner wheel ( I could be wrong)-is fixing this easy or will I end up with 39 leaves of the iris all over the place? Anyone done this-can’t find repair manual for first BH and I think they changed the Kohler illumination by second generation (I think).
Here’s photos-sporting Plan apos, achro/aplan condenser and ready to take nice video-got a phototube instead of trinocular head-I love how easy it is to remove stage and the X/Y Clip is way nicer than on a CH. and it’s really heavy so should be less wobble.
Regards ross

[BramHuntingNematodes]

Racks need grease not oil. I use lithium some people like superlube or Teflon grease I never tried but some telescope guys swear by it or thicker red grease for stiffer action but grease on racks and you don't need much

[Rossf]

Thanks BramHuntingNematodes-I meant to say grease! I’ve got some lithium grease-just to clarify the rack is the metal rail not the plastic teeth? Do I put a bit on the plastic teeth/cog as well or will it damage the plastic-I thought grease wrecks plastic but I failed chemistry big time!
Regards ross

[BramHuntingNematodes]

I mean the tooth part, although sliding surface could benefit as well. Many greases and oils are safe to use with plastic gears. I think the moly grease and graphite and ester oil are likely not good. Silicon based grease or mineral oil based grease should be fine. One of those is probably what turned into the gunk you're removing now.

[Rossf]

Thanks heaps BramHuntingNematodes!

[MicroBob]

Hi Ross,
you bought a nice looking microscope there - looks like new!
The compatability between plastics and greases varies. Since you don't know what type of plastics it is I would take no risk and use a grease that is generally plastics compatible. No grafite or MoS2 as the particles are harder than the plastics and increase the wear. I wouldn't use it dry too.

On the field aperture there is usually some grease between the actuating ring and the base. To clean the aperture components you will have to take it apart. There are more difficult jobs than this but you need patience and a steady hand for this. The aperture blades sometimes have an orientation. When reassembling you first place as many blades in their position as easily possible, one after the other without gaps. Do this in the opened position. Toward the end you have to fiddle a couple of the blades below the first blade and bring the pin into the position of the hole. This is the difficult part. In the end grease the actuating ring very lightly with instrument grease as it is use or the ways of the focus system.

Bob

[Rossf]

Thanks heaps MicroBob for the encouragement and advice-I’m not kidding I can’t find a single scratch or ding on this scope-must have been locked away in a cupboard at the University and maybe explains the stiffness of nose and condenser holder-maybe it missed out on servicing-it’s the one with the weird pre-centred bulbs only 6v/15watt but my camera is insanely sensitive so enough light for brightfield,dry Darkfield and even phase-and it’s got an entrance tube at the back if I want to beef up light with LED for wet Darkfield or whatever-didn’t come with plan apos-I collected them a few months ago-I didn’t even bid on it-a lady sent me an offer out of the blue-weird hey? A good eBay story for a change.
Regards ross

[apochronaut]

Would the track not likely be nylon? Nylon absorbs moisture, so under very humid conditions the gear sets can swell, considerably, if very wet Silicone lubricants, as well as graphite are recommended to increase lubricity of nylon gearsets and in fact decrease the tendency of nylon to absorb moisture.

[BramHuntingNematodes]

I don't know about the graphite. I use graphite grease on my objective threads, but I too have heard it might wear on nylon. Silicone grease, like super lube, is a definite yes, though.

[apochronaut]

That is probably synthetic graphite that has a warning against it. Natural graphite has been used on plastic gears as long as plastic gears have been around. I'm not a model aircraft pilot but it is apparently commonly used on the plastic gears in those things and recommended in industry as a plastic gear lube.

[Rossf]

Devils advocate-are the Olympus gears even made of nylon?-I thought that was the Achilles heel of the Nikon’s-found an interesting link about the compatibility of various chemicals and nylon-glad I didn’t start cleaning things down with isopropyl alchohol last night-apparently not good for nylon-acetone gets the thumbs up for cleaning nylon. The first nylon product was a toothbrush in 1936!

https://www.calpaclab.com/nylon-chemica ... ity-chart/

[apochronaut]

Maybe not. I think nylon got the job in many cases because the long polymer chains conferred strength. It seems to have been a popular choice for gear sets. There are other candidates though. Kevlar became popular because of impact resistance for some applications. Mylar to some degree but it stretches. Mylar drum heads can easily be deformed with one whack while they are under tensioned. I don't know plastics that well but I know someone who does. He's an Iraqui plastics engineer who now makes Shawarma in Toronto. Fortunately he didn't fuse his two professions.

[Hobbyst46]

Nylon does not resist organic solvents well. As mentioned by apochronaut, it tends to swell. I would not use alcohols or acetone - rather, light petroleum.

Today, there are excellent plastics that did not exist decades ago - PEEK for example. They are durable, tough and can be machined. Wonder if microscope manufacturers make use of them...

[MicroBob]

Common plastics for quality gears are PA of different types and POM. The former because it is tough, the latter because it combines good strength with good machinability. Just from the looks I couldn't tell which sort it may be.