I have a Curta type 1 in very clean condition. Everything operates very smoothly EXCEPT some of the setting sliders which are a little sticky when moving up and down. I’ve watched the assembly video and I’m tempted to remove the sliders and clean them but I was wondering if all I needed to do was put some clock oil on the sliders through the windows without disassembly. Do I need to clean the sliders first or can I just lubricate them?

I would open the Curta, then
- clean the axles with a cotton swab and some thinner
- move the setting sliders a few times
- repeat the cleaning until everything runs better
- finally lubricate a little, move again a few times




... ready

Theoretically also possible with closed Curta - but much less control

murff wrote:

I would open the Curta, then - clean the axles with a cotton swab and some thinner - move the setting sliders a few times - repeat the cleaning until everything runs better - finally lubricate a little, move again a few times

Thank you! What type of “thinner” and lubrication should I use?

I use a normal brush cleaner (no idea what the correct English term is) and a fine machine oil (e.g. a sewing machine oil)

With "gummy" setting knobs - do you mean the mushroom caps? if so, please remove them before working with the thinner - or be careful

Hi,

Murff advices are right but if it would not be enough (because the balls are gummy or for other reasons) you would have to dismantle and put the parts in an ultrasonic cleaner machine.
You have some pictures of this work on my site roughly at the middle of this page
https://cms.e.jimdo.com/app/scfad30cbf1de2df7/p7eb64e9e616abaf7?cmsEdit=1
(I no longer dismantle the guiding screws).
And if you dismantle the sliders, spot them with their setting shaft bearing pins.
And lightly oil only the half holes and not the grooves.

Marc Pellacoeur

As mentioned earlier, I assume that "gummy setting sliders" means mushroom caps.




They are easy to remove - so cleaning should be done without a risc, no other plastic or rubber parts are known in a Curta (except the later clearing ring and the crank)



PS: Your link leads to jimdo.com instead of https://www.curta.fr/...

murff wrote:

As mentioned earlier, I assume that "gummy setting sliders" means mushroom caps. They are easy to remove - so cleaning should be done without a risc, no other plastic or rubber parts are known in a Curta (except the later clearing ring and the crank) PS: Your link leads to jimdo.com instead of https://www.curta.fr/...

Sorry. I was using the word “gummy” to mean “sticky”. The setting sliders are sticky.