Greeting,

I just bought a great Curta II which works smootly.

The only issue is that the 10th & 11th adjustment handles can not be moved (there are stuck).

I must say that beside that, the curta works perfectly.

I'll higely apprecate your advise.

Thanks

There are different possibilities:
a) there is some dirt (grease, old oil) inside... try to put some small drops of thinner just above and below the setting knob - wait a moment and try to move it slightly. Repeat the procedure until it will be free running, wait again until the thinner is gone - then put some oil on the axle...

b) remove the complete setting knob and disassemble the knob (there is a small ball and a spring inside - don't lose it!). Then clean all separately and assembly it back to the original state... (and again some oil on the axle)

c) the axle is bent - this could be happened if the Curta was falling on the knob - you have to search for a replacement...

greeting,

as for the 1st option - is it safe to drop some thinner and oil inside the curta?

as for the 2nd option - Im not going to disassemble any curta by myself

as for the 3rd option - the axle are straight..

Quote:

is it safe to drop some thinner and oil inside the curta?

- First you should open the Curta (here is a guidance with pictures)



- Then put concerted a small drop of thinner as described (... not dropping, and only where it's needed - so it's safe)...