I purchased a Curta Type I about 6 years ago. No. 25901. It is in very good condition on the exterior. Very little wear.

However when performing a subtraction the crank catches. Gentle start & stop motions help it to complete the function. Two years ago I sent it to a repair shop in the USA with assurances that it would be fixed and returned in a few weeks. After multiple promises that it would be repaired I had him send it back to me.

What are my options for getting this Curta repaired? What repair persons do you folks trust?

I am a retired Mechanical Engineer and would very much like to play with this calculator but I am concerned that continued use will damage it further.

Your input is most appreciated.

Best references for Romano!

https://curta.org/phpBB2/viewtopic.php?t=729
https://curta.org/phpBB2/viewtopic.php?t=726
https://curta.org/phpBB2/viewtopic.php?t=696
https://curta.org/phpBB2/viewtopic.php?t=693
https://curta.org/phpBB2/viewtopic.php?t=664

and so on...


International Curta Repair and Cleaning Centre

Thank you murff.

Now the fun begins learning how to ship internarionally!

For you folks that have shipped internationally, particularly from the USA to Italy, what shipper did you use? USPS, DHL, FedEx, other?

Any tips or details to be aware of?

I contacted Romano and arranged to send my Curta to him for service. He was most helpful.

He found that several of the shafts were bent slightly. He said sometimes when it needs to be oiled it gets a bit of resistance when turning the crank and if it is forced that can bend the shafts.

He was able to correct that and clean and oil it. It now functions smoothly. Even subtracting 1 from 0 is smooth! The outside of the Curta was cleaned with something and looks almost new.

Romano even put a new foam pad in the bottom of the can and a pad on the cork spacer in the lid since it was missing.

When I purchased this Curta the white O-ring on the can was cracked and hard. The lid could not be fully screwed on. I purchased some new O-rings from an industrial supply company. They are white, fit the can, are the softest durometer available. The lid takes a fair amount of torque to fully close. By fully closed I mean the O-ring is squeezed between the can and lid, not where the lid is pushing the O-ring against the ridge on the can.

Is that normal to require a lot of torque to close & open the lid? Is there a source for the exact size and durometer of the original O-ring?

There are no documents that say what is normal.... A well-functioning canister needs a certain force to close or open. The O-ring is not critical, it only determines when the can is closed. It is important that the Curta does not "fly around" when closed - it must be firmly seated.