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thomasmanegiste
Joined: 03 Mar 2025
Posts: 3
Location: France
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 Posted: Tue Jul 22, 2025 6:28 pm Post subject: Remaking a Curta Type 1 Rev 2 |
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Hello everyone,
I'm sharing a projet I'm undertaking: remaking a curta.
The genesis of this projet goes back a little. During the lockdown, I've discovered the curta via a youtube video (https://www.youtube.com/watch?v=loI1Kwed8Pk)
A while later, I've made a tellurion (astronomic contraption that models positions of Sun, Earth and Moon).
https://www.youtube.com/watch?v=tHdg_emv9bs
https://drive.proton.me/urls/TZ1V4R16ZG#g7BRQ7PPiLVf
After making this contraption, I've decided to start making a curta. At first glance, it seems extremely complicated, due to limited mechanical plays, clearances for oil films...
I think this is doable (whithout questions of profit or time), because of the exceptionnal conception : each part is not so complicated. I think this conception was driven by the need to manufacture in high quantity, whithout numerical controlled machines.
The goal of this project is to make a fully fonctionnal Curta Type 1 Rev 2, 1:1 scale. I'm using the original drawings, and I try to buy less tools as possible (I'm making my own special profile mills for gears).
https://drive.proton.me/urls/SB7YSGAQ0C#kcmVdO47eQIq
https://drive.proton.me/urls/X0C3ZZGXZW#xA09qFIgmE0t
I'm currently working on the different gears :
-Counters sliding gears (10038):
https://drive.proton.me/urls/Y3787SAJSG#8pVBM7FVFdaA
These are made out of .5mm sheet metal, then mounted on brass hub (10017, 10020 or 10032)
-Frontal counter gears (10052):
https://drive.proton.me/urls/42XP9E5F10#QZmRcWRIpsvt
https://drive.proton.me/urls/7P567BTBQW#xakU6BPWJB0q
-Counters rollers (10045):
https://drive.proton.me/urls/WSQZHMMRSW#fpXsFju4ZocH
For those parts, I'm planning to use shrink fit workholding fixture to machine the gear.
This project is progressing slowly, as I don't have much time to devote in it (studies etc...).
Let me know if you want regular updates or a deeper view of the machining processes.
One last word: the goal is not to have a 100% conform replica. I'm adjusting the original conception to the available materials, for example the tolerances are varying from the original. I'm also planning to add some interesting features, such as the Silent Curta spring, that weren't implemented on Type 1 Curtas.
Have a nice day,
Thomas.
Last edited by thomasmanegiste on Fri Jul 25, 2025 7:03 pm; edited 2 times in total |
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murff
Joined: 27 Oct 2009
Posts: 601
Location: Switzerland
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| Posted: Wed Jul 23, 2025 3:07 pm Post subject: |
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What an exciting project!
Which variant do you want to build? I hope an all-metal version... should it succeed -
do you want to produce a small series? I would like to preorder serial number 0002!
How do I get access to the documents? Do I need an account?
(update - I just created an account... interesting pictures!)
I would love to get regular updates on your work!
I wish you good luck and much success!
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:: curta.li
Last edited by murff on Wed Jul 23, 2025 7:21 pm; edited 1 time in total |
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Kmcqueen
Joined: 14 Apr 2023
Posts: 35
Location: Portland OR, USA
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| Posted: Wed Jul 23, 2025 5:10 pm Post subject: |
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| I would be interested also - Let me know what to do get access to your photos. I've been trying to picture the process for cutting that spiral groove into the setting shaft for years (without using CNC). I'll be curious to see how you pull that off. |
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thomasmanegiste
Joined: 03 Mar 2025
Posts: 3
Location: France
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| Posted: Fri Jul 25, 2025 9:24 am Post subject: |
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Hello everyone !
| Quote: |
Which variant do you want to build? I hope an all-metal version... should it succeed -
do you want to produce a small series? I would like to preorder serial number 0002! |
I'm buiding two versions: one all metal, and one with an acrylic outside to see the guts.
I would like to build a serie of curtas, but there are several problems :
-Price : because I can't produce in big quantities, the price will be extremely high. I might sell whithout profit, just for fun, but it will probabely be a thousand at least.
-Technical industrialisation difficuties : to be able to produce several machines, I need to invest in CNC machines (swiss turning center, 3 axis mill), and to rethink my whole process to be more effective.
Depending on how many people want one, I might explore possibilities of serial production. If not, I might make one more for you 
| Quote: | | I've been trying to picture the process for cutting that spiral groove into the setting shaft for years (without using CNC). I'll be curious to see how you pull that off. |
The principle is to link a linear move (X), with a rotary move (using a rotary table). It might be a little headache, as I don't have a universal rotary table, but it is still possible with a few gears and modifications of my conventionnal mill.
https://youtu.be/uaJsgsLkwQg Example for manufacturing a counterboring mill.
| Quote: | | Let me know what to do get access to your photos |
I don't know why you can't have access to those. Do you mean you can't open the links in my first post?
Let's try this:
[img] https://drive.proton.me/urls/PDTXGCC7MW#BaQEmzgNdeQH [/img]
Tell me if you can see this one. If not, can someone explain me how I should put images? I'm using the img and /img tags.
Have a good day! |
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murff
Joined: 27 Oct 2009
Posts: 601
Location: Switzerland
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| Posted: Fri Jul 25, 2025 10:33 am Post subject: |
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| thomasmanegiste wrote: | Hello everyone !
| Quote: |
Which variant do you want to build? I hope an all-metal version... should it succeed -
do you want to produce a small series? I would like to preorder serial number 0002! |
I'm buiding two versions: one all metal, and one with an acrylic outside to see the guts.
I would like to build a serie of curtas, but there are several problems :
-Price : because I can't produce in big quantities, the price will be extremely high. I might sell whithout profit, just for fun, but it will probabely be a thousand at least.
-Technical industrialisation difficuties : to be able to produce several machines, I need to invest in CNC machines (swiss turning center, 3 axis mill), and to rethink my whole process to be more effective.
Depending on how many people want one, I might explore possibilities of serial production. If not, I might make one more for you
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OK - I'm there! The early bird price is right 
An acrylic case for the Curta series would be cool!
I'm sure a lot of people would be interested in that...
... the historical model:
https://digital.deutsches-museum.de/de/digital-catalogue/collection-object/78037/
PS: The image tags work perfectly - you need to make sure the image source is freely accessible
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thomasmanegiste
Joined: 03 Mar 2025
Posts: 3
Location: France
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| Posted: Fri Jul 25, 2025 12:37 pm Post subject: |
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@Kmcqueen
I changed the way I put pictures in my posts. Let me know if it's working for you. |
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murff
Joined: 27 Oct 2009
Posts: 601
Location: Switzerland
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Kmcqueen
Joined: 14 Apr 2023
Posts: 35
Location: Portland OR, USA
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| Posted: Mon Jul 28, 2025 3:29 pm Post subject: |
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| The new links work for me! Thanks! Also thanks for the machining video - makes complete sense now. I had originally looked at the grooves under magnification and though maybe they were made on a shaper.....but couldn't picture how to get the spiral twist. |
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