Typewriter Talk / interchangability of Lettera mainsprings

**Posted by lazydog** 27-10-2022 13:35:18

Are they? As in, do you suspect the spring of a 197x Lettera 35i would fit a mid 50s Lettera 22? Asking for a friend who is scared to try to fix a broken mainspring...

**Posted by lazydog** 27-10-2022 15:08:56

I am assuming I am correct that if you try to wind up a spring (in the correct direction), and after one rotation or so it clicks and loses tension, it is broken or detached. Right? I have two L22s and both arrived with broken springs. 70 year-old machines, so not unexpected -- but still, bummer.

**Posted by Laurenz van Gaalen** 28-10-2022 01:37:57

Yes, I think your assumption is right. I had the same with my first Halberg. At that moment I was under impression the Halberg was a rare machine, so finding an original replacement seemed not an option. Because I had nothing to lose, I decided to try to repair the spring motor. It turned out not to be difficult to open the spring motor, so I was able remove the broken part and reattach the spring.

**Posted by thetypewriterman** 28-10-2022 04:51:18

I would also add that maybe, just maybe, the mainspring isn't broken at all. It could just be detached at the centre and the hook on the spring is riding over the axle as you try to tension it. Certainly worth trying to get the spring drum open to check.

**Posted by lazydog** 28-10-2022 17:24:54

Laurenz van Gaalen wrote:
It turned out not to be difficult to open the spring motor, so I was able remove the broken part and reattach the spring.

Not my experience! Cracking open these little Olivetti mainsprings is a bear. There also seems to be a little tab designed to pop into place when it is first closed, which maybe could be forced out of its slot with a screwdriver -- but when I tried that with another one it just kind of mangled it and didn't budge. What could free up those tabs? 3 in 1 oil? Just plain ol' hand torque? I can't squeeze and turn any harder!

UPDATE: turns out one of my other boneyard Olivetti mainsprings was NOT in fact broken, and the L22 is back in service, if still a little clunky. So the 35i lives to see another day in any case.

Original question: solved! How to open Olivetti mainspring: still perplexing. I hope it is just unhooked, thetypewriterman! But I gotta be able to OPEN it to SEE...

Actually hoping to fix one to put back in my Underwood 21 -- which attentive readers might remember I raided for its spring months ago to resuscitate my Studio 44. Oh the drama! I do think that the Studio and Lettera mainsprings of that era (early 60s) seem identical except for a longer bolt...which would certainly make sense from a manufacturing point of view. Can anyone confirm?

**Posted by lazydog** 28-10-2022 22:53:12

Annnd the other mainspring wasn't broken after all. U21 back in service. I think I just know what is going on better now than I did six months ago. And I have reattached three or four drawbands by now too. Learning by doing! I will post pics tomorrow of all my Olivetti and Olivetti-adjacent beauties. They are such wonderful machines.

**Posted by Laurenz van Gaalen** 31-10-2022 15:05:14

lazydog wrote:
I do think that the Studio and Lettera mainsprings of that era (early 60s) seem identical except for a longer bolt...which would certainly make sense from a manufacturing point of view. Can anyone confirm?

I think you are right. The Studio 44 spring motor from my parts collection looks the same as the spring motor inside my Olivetti 22, except for the longer bolt.

I also found a DL spring motor. It seems to have the same diameter, but it is not as heigh. The bolt is very short, I doubt if it will fit in the mounting of the Lettera 22.

**Posted by Pete E.** 02-11-2022 17:39:17

I ended up with a spare main-spring from an Underwood-Olivetti 21 I parted out.

Looks like it will work for both my Lettera 22 and my Lettera 32.