A rather stiff Jupiter-9

[GeorgesGiralt]

Hello !
I've got a nice KMZ Jupiter-9 (1957 vintage) which was quite sstiff on focussing and smelling awfull.
Today, I dismantled it to clean it and re-lube. But it is still stiff ! It works fine with all threads un greased but become rather stiff whatever grease I use (a silicone one from Loctite, a totally synthetic grease used to keep O-ring seals pristine in adverse condition from Molykote, a teflon based grease used for bike chain lubrication).
So my questions are :
1) is it possible to put oil instead of grease (I think about oil for rear axle gears) ?
2) will it be harmed if I let it dry ?
3) why is it so stiff ? (I'm sure to have re assembled correctly because I can focus on infinity and 1 m, checked both with RF and ground glass.
Oh, BTW, I'm good at disassembling/rea ssembling a J-9 ..... Grrrrr......
TIA !

 

[Xmas]

I only use a PTFE liquid lube (one drip of), from Tandy, or gun shop, etc. it is not a pukka oil, so pin point of grease on each wear point if you are picky may be desirable, but unnecessary for me...

It is not good for metal to metal contact like real lube, but will keep you going 40 below. It wont migrate on to optics like oil.

Noel

 

[Kim Coxon]

The best thing to use is a very thin synthetic grese. It is very easy to apply too much. Oil or any oil based grease will "bleed" and end up where you don't want it. This is not too much of a problem with an RF lens due to the manual aperture but oil will only last a fraction of the time of a good grease.

As James said, each helix will seem to be fres but once all three combine, it will seem stiff. This is not so much a lack of lubricant but the "force" needed to "drive" the other sections.

Kim

 

[colyn]

Hello !
I've got a nice KMZ Jupiter-9 (1957 vintage) which was quite sstiff on focussing and smelling awfull.
Today, I dismantled it to clean it and re-lube. But it is still stiff ! It works fine with all threads un greased but become rather stiff whatever grease I use (a silicone one from Loctite, a totally synthetic grease used to keep O-ring seals pristine in adverse condition from Molykote, a teflon based grease used for bike chain lubrication).
So my questions are :
1) is it possible to put oil instead of grease (I think about oil for rear axle gears) ?
2) will it be harmed if I let it dry ?
3) why is it so stiff ? (I'm sure to have re assembled correctly because I can focus on infinity and 1 m, checked both with RF and ground glass.
Oh, BTW, I'm good at disassembling/rea ssembling a J-9 ..... Grrrrr......
TIA !

I used white lithium grease on mine and it works fine with just the right amount of resistance.

 

[GeorgesGiralt]

Hi ! It's me again.
I've played a lot with it today (and yesterday night, for that matter) ...
I've bought lithium grease, a teflon grease, a graphite grease, a teflon spray (oil) and a teflon spray (grease).
I've testes my J-9 WITHOUT grease and it was way too smooth.
With all greases, it is too stiff. The worst being the graphite one which is rather thick.
So my last attempt was with the teflon grease (a very thin coating) lightly thinned with the teflon oil (spayed in a can and put with a stick in the threads) and las t but not least, the locking pins where lubricated with the teflon grease (they had quite a lot of play due, I think, to lack of lubricant or huge use of this optic.
Now, it focuses smoothly as silk !
I've made a test roll and I'm going to dev. it to see what I've got !
Thanks to all who answered and provided help !
If you've got questions about the J-9, ask ;-)