Shims to adjust the FSU lenses -- where to find them?

xoDox

xoDox

Member
Local time
6:12 AM
Joined
Jan 23, 2007
Messages
45
Hi everybody,

Can anyone suggest a source for calibrated shims to adjust LTM lenses to RF body? Recently I've used empty tins to cut out the shims for J-3 and old LTM Sonnar 1.5/50mm. It took a lot of time, but worked very well; however, I would prefer to deal with calibrated shims to achieve more precise focusing. Thanks for your help.

Vassily
 
For finer adjustments, you can use paper in various thicknesses. Solid strand copper wire can also be used. But to get those metal rings, you'd have to customise them, or do what you've done- cut the shims yourself. I think it would be difficult to get those shims ready-made. They have to be made in different shapes and sizes as well as thicknesses to fit the lenses individually. The best bet is to use shims from other lenses.

There is a J-3here waiting to be recalibrated. It has lost its shims from a previous repair- these had been transplanted to another lens. I will perhaps be using copper wire and paper to shim them.
 
Thanks for response and for ideas to use paper or copper wire for hand-made shims. I didn't go that far:D. Once I dismantled a Nikon AF lens and was surprised to find lots of ready-made shims inside. They were made of brass or alike metal. I am thinking there shouldn't be any problem to make similar for LTM lenses. I suppose they don't need customization -- the inner and outer diameters are predetermined by the mount size...

Unfortunately nobody cares to bring LTM shims to the market.
 
Sorry, what's this a"pipe tape"? It does sound like a teflon based tape. Am I right? I'm looking for more solid substance like copper or brass, but maybe I' m wrong here and plastic works fine.
 
xoDox said:
Sorry, what's this a"pipe tape"? It does sound like a teflon based tape. Am I right? I'm looking for more solid substance like copper or brass, but maybe I' m wrong here and plastic works fine.
Click to expand...

pipe tape is used to seal the threaded parts of pipe fittings and pipe.
it is odd stuff to use in theory, but in practice it worked like a charm.
 
Model making places sell the propper brass shim stock in small packs.

the thin stuff cuts OK with a Swan-Morton blade in a compass or just with scissors if you have a steady hand
 
xoDox said:
Thanks for response and for ideas to use paper or copper wire for hand-made shims. I didn't go that far:D. Once I dismantled a Nikon AF lens and was surprised to find lots of ready-made shims inside. They were made of brass or alike metal. I am thinking there shouldn't be any problem to make similar for LTM lenses. I suppose they don't need customization -- the inner and outer diameters are predetermined by the mount size...

Unfortunately nobody cares to bring LTM shims to the market.
Click to expand...

The idea of using paper and copper wire for shims came from there :). The old Russian repair books mention this.

Shims have to be cut according to the lens they will go into. For instance, each Jupiter type's lens block has its own uniquely shaped barrel diameter. The shims put there by the factory were custom cut, in batches of course for use in these particular lenses. Outside and independent of the factory, making shims of varying sizes, diameters, and with different hole sizes and thicknesses at that would be quite impractical. This isn't like cutting washers for use with standard bolts and screws, where one or two sizes can work.
 
I slice-off brass or alloy ones, in the lathe - as and when needed, if you are stuck, I could possibly help, but would need some measurements - bore diameter, outside diameter, and of course thickness.
Dave.
 
Thanks Sparrow, xayraa33 and ZorkiKat for the new ideas. Regarding paper use for shims, if I remember right it was some sort of impregnant technical paper... Pls. correct me if I'm wrong. I would avoid using an ordinary paper since it gets wet easily.

Dave, I don't think the shims of 0.01мм thickness (and less) can be made in the lathe. I'm sure they are stamped!
 
You must log in or register to reply here.
Back
Top Bottom