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Bruce B
16-Dec-2012, 09:07
Hi,

I'm wanting to remove the dirt of the Ages from the shift slides of a Sinar F+ and replace the lubricant. And give both standards a good cleaning in the process. Removing the frame from the shift slide is easy (and reveals the slide could really use a lubricant replacement), but I haven't the slightest as to what lubricant to use. What's on the slides now looks like plumbers' high temp grease, but looks can be deceptive.

Also, there's a noticeable slack in the focus rack on the rear standard. Any suggestions for tightening that up would be helpful. I suspect this might involve a new rack, since it appears to be nylon or similar polymer material.

Thanks in advance,
BAB

Bruce B
19-Dec-2012, 17:49
Moly grease, or molydenum disulfide lubricant, according to an old hand at repairing cameras.

BAB

Bernice Loui
20-Dec-2012, 21:37
Remove the two knurled thumb screws on the bottom of the rods by heating them up. These are held in place with Loctite. Heat is needed to break the Loctite bond.
Once these are removed the frame with rods can be removed from the holder.

What usually causes the sticking rise/fall on these Sinar standards is a cracked gray plastic piece (rectangle) that is pressed against one of the rods by the lock screw or planetary gear driven screw that lock the rod's position.

Replacing broken gray plastic piece and cleaning the rods and holder usually makes it all better.

As for lube, Dupont Krytox very sparingly.


Bernice

Drew Wiley
21-Dec-2012, 09:45
The delrin focus gears are shimmed. You don't tighten them per se, but if necessary, add
an extra shim. This requires taking the assembly apart. I don't know who has the service
parts now. The only time I ever needed to do this, Sinar Bron had the shims in stock.

Bruce B
22-Dec-2012, 07:14
Bernice,

Thanks for the reference to Krytox. What's your opinion of molydenum disulfide grease for the left/right swing plates? I don't have any stickiness with the rise and fall rods, but your advice there is much appreciated.

BAB

Bruce B
22-Dec-2012, 07:18
Thanks, Drew. Shims are available locally, but I've not yet disassembled the rack and pinon assembly. Looking more carefully at the slight wobble, I'm not certain it's the gear assembly to blame. Truthfully, I may be nitpicking, as 1.) this Sinar model is light in build, and 2.) the shutter is on the front standard, so what's to worry :).

But thanks again for the advice,
BAB

Bernice Loui
22-Dec-2012, 22:37
Depends on the soap base used to make the moly grease. Most common is lithium base mixed with fine moly powder. Less common is synthetic moly grease.

Not really needed for camera mechanicals as moly is designed for high pressure bearing loads, not found in camera mechanicals. One of the most common places moly grease is use, CV joints in cars.

What usually happens to the lubricant in Sinar moving parts, the lube (grease) dries out and becomes very stiff over time. Reasons for Krytox, it is teflon based and does dry out in the same way as dino base lubricants.

Bernice



Bernice,

Thanks for the reference to Krytox. What's your opinion of molydenum disulfide grease for the left/right swing plates? I don't have any stickiness with the rise and fall rods, but your advice there is much appreciated.

BAB

Bruce B
23-Dec-2012, 10:50
Molydenum disulfide is, indeed, a high pressure lubricant, but it's also a very slippery substance. Unfortunately, the grease I acquired IS in a hydrocarbon (dino) base. Considering the expense of the Krytox, it could still be OK for large sliding surfaces, especially those easily reached for cleaning/replacement.

I've emailed Dupont for a price list / source of the Krytox, and I'm wondering which of the many Krytox formulations you currently use/recommend.

Thanks again,
BAB

rdenney
23-Dec-2012, 11:20
Grease is just oil emulsified using soap. Mineral oils are volatile at some level, and eventually evaporate away, leaving the soap. That hard, crusty stuff when grease is too hold is just that.

Moly-Disulfide is an additive to the emulsion that fills it with molecules that will bind to metal substrates and resist being pushed aside. That's what makes it work so well for non-pressurized lubrication systems like in CV joints. Do avoid the volatile oil carrier, I get Valvoline Synpower, which is 100% synthetic and has a very low evaporation rate. But many of these synthetics will also allows the oil to separate from the soap if it's not exercised.

The problem with moly-fortified grease is that it profoundly stains anything it touches. I don't want a camera that I have to worry about leaving a spot on my clothes that can't be washed out.

The other problem with grease is that it is a dust magnet, and the dust that sticks to it is abrasive.

So, I have always used a teflon-bearing light machine oil or grease, such as that made for fishing reels, very sparingly. Clockmakers oil clock bearings using an oiler that retracts most of the oil it applies to prevent the excess that becomes a dust magnet. Just a film is necessary. Nothing on the camera applies the sort of bearing pressure that needs an additive like Moly-Disulfide.

For me, the drag on F rise/fall columns can be caused by a stiff or frozen detent ball assembly. One of my F standards was used that way for a long time, and it actually wore grooves in the column. (The standard still works fine, but my current assemblage uses F2 standards.)

Rick "just some randoms thoughts" Denney

Bruce B
23-Dec-2012, 13:51
I certainly agree with the dust magnet statement. Could you provide some more detail about teflon-bearing oil, as in brand names and suppliers. Other than LL Bean :) And/or the applicator for clockmakers. (Actually I know a clock repairman and should probably contact him as well.) The reason I haven't just gone ahead and put lithium grease with a dusting of moly powder (I have both) on the slide is I wanted to avoid the both the drying out of the lubricant base and also the problem with the soiling of anything in contact with the grease. Not to mention the collection of dust and grit. Yet it seems unwise to leave the bare metal surface without any sort of lubrication. So far the Krytox seems the best option but I'm open to all suggestions that work AND are easy to clean and replace. Grease is neither of those, as you indicated.

Perhaps camera-makers should use easily replaced bronze/steel bushing surfaces :).


Grease is just oil emulsified using soap. Mineral oils are volatile at some level, and eventually evaporate away, leaving the soap. That hard, crusty stuff when grease is too hold is just that.

Moly-Disulfide is an additive to the emulsion that fills it with molecules that will bind to metal substrates and resist being pushed aside. That's what makes it work so well for non-pressurized lubrication systems like in CV joints. Do avoid the volatile oil carrier, I get Valvoline Synpower, which is 100% synthetic and has a very low evaporation rate. But many of these synthetics will also allows the oil to separate from the soap if it's not exercised.

The problem with moly-fortified grease is that it profoundly stains anything it touches. I don't want a camera that I have to worry about leaving a spot on my clothes that can't be washed out.

The other problem with grease is that it is a dust magnet, and the dust that sticks to it is abrasive.

So, I have always used a teflon-bearing light machine oil or grease, such as that made for fishing reels, very sparingly. Clockmakers oil clock bearings using an oiler that retracts most of the oil it applies to prevent the excess that becomes a dust magnet. Just a film is necessary. Nothing on the camera applies the sort of bearing pressure that needs an additive like Moly-Disulfide.

For me, the drag on F rise/fall columns can be caused by a stiff or frozen detent ball assembly. One of my F standards was used that way for a long time, and it actually wore grooves in the column. (The standard still works fine, but my current assemblage uses F2 standards.)

Rick "just some randoms thoughts" Denney

Armin Seeholzer
24-Dec-2012, 14:22
I used Vaseline after the cleaning some years ago and I'm still happy with it! But not much just a very fine film!

Cheers Armin