The Curta.org Bulletin Board

[Paul1967]

I've decided to give it a go.

When I am done I'll either have a nice looking fully functional Type II or a very pretty paper weight.

Either way I will gain more knowledge of the Curta

[murff]

start here:




Dismanteling & Reassembly

good luck !
_________________
:: m u r f f
:: curta.li

[Paul1967]

Thank you for the link and the good wishes. I have downloaded the oiling chart too so I can lube it as I go.

[Paul1967]

An update for anyone interested

I believe I have identified the problem that was causing the jamming.

The carry piece that moves up and down and has a finger that sits between two rows of teethon the carry cog was actually pressing onto the lower teeth rather that in the gap.

I have pushed the carry cog back into place.

A few days ago, before I took it apart, after gently working it until it started to jam, after a while it ran smoothly, but that lasted about 5 minutes.

Looking at the finger, it is not angled the same as the others and I guess this is why after appearing to cure itself it failed again.

A little tweak with a pair of pliers is all that is required but I have to get it out first.

I do not feel that brave at the moment. I need to look at some more photos for a while That little spring is what is worrying me.

[mwu]

Awesome, I'm definitely interested in updates.

Yes, that's a carry lever. On the Type I there are screws that hold the levers in place. It looks like the Type II doesn't have those and they just slide in / out. Without the screws, they would have to have less vertical play or a tighter fit than they do on the Type I (not sure which -- I haven't studied the engineering drawings of the Type II as much.

I've never handled one, but I know those levers are small and it probably doesn't take much to bend them. I've accidentally broken a few 3D printed ones. Is the carry lever bent or just at a bad angle? Can you share a picture?

[Paul1967]

Before I started this repair, I was going to document it fully photographically.

When it came to it I didn't take a single photo

I noticed on the disassembly photos that the Type I and II differed somewhat as regards the carry levers (and the revering lever)

I found the courage to lift out the carry lever and while holding it all carefully put the finger part into a mini vice and gave little push and that was enough.

Putting it back in was tricky and inevitably it flew apart. Luckily there are numerous other ones to copy to se how it was supposed to go.

I got it back in ok. The alignment is automatic as the brass part that the lever slides against has protrusions top and bottom that sit outside of the aluminium top section the it pushes into.

The hardest part of the whole thing was trying to align 8 cogs as I was refitting the reversing lever.

I was going to lubricate it but it seems to be working smoothly anyway and I didn't want to oil things I shouldn't so left it as it was.

It is working perfectly now.

The only casualty was the red subtraction paint that flaked off while removing the pin from the crank.

I feel I know my Curta a little better now

[mwu]

That is awesome and great to hear! Well done!

[2010*smiths]

Well done, I'm impressed! Thanks for documenting the process.

[danbrew]