Recommend grease?

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PeteM
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Re: Recommend grease?

#31 Post by PeteM » Fri Dec 14, 2018 4:46 am

Helicoid grease will have a high shear strength, making it a bit harder to turn the nosepiece.

I'd think a standard NLGI 2 grease would work. The original was probably petroleum based. Clean everything and you could switch to a synthetic base.

apochronaut
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Re: Recommend grease?

#32 Post by apochronaut » Fri Dec 14, 2018 2:15 pm

I have been unable to locate that lubricant list from AO, previously mentioned. Some of them were proprietary, some blends, and some were commercial brands. There were about 10 or 12 in all. However, when it comes to rack and pinions and ball races in nosepieces, what one company used was probably pretty close to what another used. In both cases, the idea is to provide lubrication but also a degree of clutching which confers smoothness to the motion. As parts wear there is some degree of adjustment available in many cases, in order to keep an acceptable tolerance. With rack and pinions, there can develop a slightly loose section where most of the focusing action has taken place. When there is a small degree of play, it is preferable to increase the viscosity of the grease, rather than decrease it.

With ball race nosepieces, they can be anywhere from firm and smooth to slick and slippery. The circumference of the nosepiece and size and number of bearings all affect that. I've seen all kinds of arrangements; the large 6 place nosepieces can have as many as 40 or more tiny bearings and I've seen as few as 6 big ones. Microscopes are all different and the various clickstop mechanisms are designed to capture each design as precisely as possible. Generally , I've been using Nye 362 HB for nosepieces. It has both lube and enough tack qualities to do the job, especially where there is also the facility to adjust tensioning.

For what it is worth, here is the lubricant list for the B & L Balplan. Nyogel( Bausch & Lomb KG-224), Bausch & Lomb KG-208, Bausch & Lomb KG-290, Glide Stage Grease Bausch & Lomb 31 50 04 0000. So, they are pretty specific about the qualities of the different lubricants used. 3 of them appear as though they might be proprietary, made for B & L by a grease mfg. I remember that in the AO list a couple were from a small local N.Y. state mfg. and one was a Mobil product.
Nyogel, is a well known silica grease but comes in a bunch of formulations, so the B & L list doesn't tell us much. However, they do have a fairly substantial steel worm drive in the back of the Balplan for the focusing mechanism and they use the Nyogel KG-244 on that and the rest of the focus mechanism parts. I would put my money on that being something like the current Nyogel 788, due to it's rust resistant prperties, although I don't know what formulations Nye was offering in 1975. The the slide and thrust focus bearings on the Balplan are self lubricating ball bearings.
The other points of lubrication are the glide stage, which I am guessing uses the glide stage grease.
Then there is the interpupillary distance slide and the telan lens sachet, which both appear to use the KG-290, while the diopter pirouette , condenser cascade and nospiece axel must be the KG-208. Probably if it is a double or triple axel, then superlube might be necessary.

PeteM
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Re: Recommend grease?

#33 Post by PeteM » Fri Dec 14, 2018 7:00 pm

FWIW, I recently tried Nyogel 767A grease on an Olympus BX turret. While rated as a NLGI #2 grease, it's actually meant for heavy damping. Reason I tried it is because the nosepiece had to be disassembled and there were two rows, one with scores of tiny bearings, that had to be stuck and then stay in place for re-assembly. Tedious process - pick up bearing with forceps, place in bed of grease, repeat . . .

While it doesn't matter too much in a nosepiece, it's really too viscous IMO. That particular Nyogel is when you have a fair amount of clearance and want to give something a sort of slow silky-smooth movement. It would also likely be far too viscous for helicoid focusing rings.

Hobbyst46
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Re: Recommend grease?

#34 Post by Hobbyst46 » Fri Dec 14, 2018 9:28 pm

PeteM wrote:FWIW, I recently tried Nyogel 767A grease on an Olympus BX turret. While rated as a NLGI #2 grease, it's actually meant for heavy damping. Reason I tried it is because the nosepiece had to be disassembled and there were two rows, one with scores of tiny bearings, that had to be stuck and then stay in place for re-assembly. Tedious process - pick up bearing with forceps, place in bed of grease, repeat . . .

While it doesn't matter too much in a nosepiece, it's really too viscous IMO. That particular Nyogel is when you have a fair amount of clearance and want to give something a sort of slow silky-smooth movement. It would also likely be far too viscous for helicoid focusing rings.
I decided to try and replace the old grease inthe focusing rack of my Stereoscope with Nyogel 767A. I like the result - it is damping and prevents the head from sliding down when the knobs are not tightened.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

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wporter
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Re: Recommend grease?

#35 Post by wporter » Fri Dec 14, 2018 11:35 pm

Well I have bought many types of the so-called helicoid grease and sad to report NON have the properties of the OEM zeiss grease
Some of this below echos others:

I occasionally use a helicoid grease some places on microscopes, but not often. It is Helimax-XP ("optical and Instr. helicoid grease w/ lithium & PTFE white- NLGI#1"), and I now only use it on multi-threaded focusing eyepiece tubes (also good there on telescopes). A thin grease, but 'holds its shape'. Used a lot by camera lens repairmen. Has to be thin since the mating surfaces can have many square inches/cm of contact area.

For lubing objectives, a consideration is the volatility of the grease (mass-loss over time), since the volatiles may plate out on your optical surfaces. I've taken to using DuPont Krytox GPL-207 on the helices of objective internals, it's a synthetic with extremely low outgassing.

also:

1) the old grease might have hardened up considerably in your old scope, so you may want to replace it with something that is not so much like the tar you're cleaning off.

2) as many have pointed out here, the consistency is important; the final operational 'feel' you want for that particular part determines the grease.

3) many parts could actually benefit by lubing with oil, rather than grease; this is judgment call. In many cases, grease is used because it is less messy during factory assembly, and/or stays in place better.

4) open gears & racks & ball-bearing races (like in many stages where you can actually see the bearings & races) probably should not be lubed at all, since this holds grit, dirt, and dust in the mechanism necessitating more frequent cleanings. Just lube the pinion shafts with some light oil.

5) dovetails are a special exception to 4), either oil or grease can be used in a thin film to get the sliding action desired.

6) if a non-optical sliding part that you know is supposed to move, doesn't, try seeping a little naptha into the cracks & let sit for a half hour and try moving it again. Repeat this until you can get it to move; when you think the naptha has dissipated, seep some of a 50-50 mixture of naptha and your favorite light synthetic oil into the cracks & work it back and forth. This may make the part operational until you can get time to dismantle it for cleaning (which may turn into forever...lol).

rs6000
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Re: Recommend grease?

#36 Post by rs6000 » Sat Dec 15, 2018 4:37 pm

Thank you for all your replies most you have been most helpful
what I did not mention was some of my outcomes and results of using the various lubes I have aquired none have been successful :?
But as I rotate the 5 place turret the ball race grinds as the balls mysteriously slip out only after a few rotations? I had set the preload to a point that is IMHO not to tight Binding but not to loose so there's slop
maybe there is a specific torque setting that is necessary other then just snuggling the reverse thread screw in till you think its good sadly I dont have access to a official service manual nor does any one else I think Esp on a 1974 vintage device :(

MichaelG.
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Re: Recommend grease?

#37 Post by MichaelG. » Sat Dec 15, 2018 5:09 pm

wporter wrote:
Personally, I'm not sure why a silicone based grease would be more likely to get all over anything than any other grease.
You're probably right. I guess what I don't like about silicone-based lubes is the persistent slick feel, even after wiping off with a rag, say [ ... ]
This may be related to the well known problem with Silicone-based horological lubricants.
Epilame treatment is recommended, to 'ring-fence' the pivot holes and prevent migration.

See page 28-14 of this document [ p14 of the PDF ]
http://horotec.ch/file/EN_28v.pdf

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MichaelG.
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Re: Recommend grease?

#38 Post by MichaelG. » Sat Dec 15, 2018 5:22 pm

apochronaut wrote:I have been unable to locate that lubricant list from AO, previously mentioned. Some of them were proprietary, some blends, and some were commercial brands.
[ ... ]
For what it is worth, here is the lubricant list for the B & L Balplan. Nyogel( Bausch & Lomb KG-224), Bausch & Lomb KG-208, Bausch & Lomb KG-290, Glide Stage Grease Bausch & Lomb 31 50 04 0000. So, they are pretty specific about the qualities of the different lubricants used. 3 of them appear as though they might be proprietary, made for B & L by a grease mfg. I remember that in the AO list a couple were from a small local N.Y. state mfg. and one was a Mobil product.
This may be of interest:
With apologies for not crediting the photographer:
With apologies for not crediting the photographer:
IMG_1424.JPG (78.31 KiB) Viewed 3038 times
N.B. its characteristics differ from those of a modern product with the same name.

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PeteM
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Re: Recommend grease?

#39 Post by PeteM » Sat Dec 15, 2018 7:03 pm

MichaelG. wrote: . . .
Epilame treatment is recommended, to 'ring-fence' the pivot holes and prevent migration.

See page 28-14 of this document [ p14 of the PDF ]
http://horotec.ch/file/EN_28v.pdf

MichaelG.
Thanks for posting that, Michael. Seems like silicone-based lubes might be less likely to have components outgas -- but also more likely to see the oil migrate??

MichaelG.
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Re: Recommend grease?

#40 Post by MichaelG. » Sat Dec 15, 2018 7:35 pm

PeteM wrote:-- but also more likely to see the oil migrate??
That is my understanding, Pete

I am not a watchmaker, but I do know some, and they use Epilame treatment as a precaution.

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wporter
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Re: Recommend grease?

#41 Post by wporter » Sat Dec 15, 2018 11:24 pm

But as I rotate the 5 place turret the ball race grinds as the balls mysteriously slip out only after a few rotations?
Sounds like something else is wrong. The balls are in many cases retained from moving out of place by a brass ring with bearing sized holes in it; if it doesn't have one of those, then maybe the parts are not drawn up close enough to keep the balls in the track(s). It should not be possible for the balls to escape the track if the two halves of the track-containing parts are together enough. Take it apart, butter up the tracks with grease (a nice #2 grease), press the balls into the track where they will stay embeded in the grease, and then put the other half carefully on, and button it up, being careful not to shift things while doing so. From the 'grinding' noise I'm suspecting that one of the balls has escaped the track during reassembly and the halves are not going together all the way, and the loose ball holding the halves apart is being crushed (grinding as you rotate the turret).

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Radazz
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Re: Recommend grease?

#42 Post by Radazz » Mon Jan 14, 2019 3:45 am

PeteM wrote:I've used Dow M-kote 44M as a medium grease (NLGI #2 consistency, same as SuperLube). It's a white, silicone, high temperature grease. Far as I can tell the main plus is that, as a high temperature grease, it is less likely to either have volatile fractions evaporate or stiffen up in time. That makes it good for things like the slides in trinocular heads. I just used it to lube the fine focus gears in a Nikon Optiphot. It's not as sticky as the original grease, but in this case I wanted very free movement due to the fine focus gear problems these often have. I kept a heavier grease on the coarse focus bits. We'll see how it all holds up.

Dow also makes a silicone grease for helical focus mechanisms that's good for focusing eyepieces.

The main minus of a silicone grease might be that it likely requires complete removal of the old grease, since silicone and traditional greases are often incompatible.
I have been using naptha in the form of lighter fluid to remove old grease. Melts it immediately, and thoroughly cleans it. I grease immediately after cleaning.
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