Two new-old-stock Olivetti Divisumma 24

[Cristian Arezzini]

Hello, a few days ago I found at a local thrift shop, an unexpected deal. There were two Divisumma 24 machines side by side. They caught my attention because you don't usually see two identical machines at such places.

I checked them out and they looked practically brand new. They're from the later batches. No scuff marks anywhere, no dirt, no signs of rust, almost no marks on the paper roller. One even had a pristine power cable. I took off the cover, and the insides too looked brand new, with no dirt or rust anywhere, and all the small "dabs" of yellow grease still looking untouched. The owner said they're NOS and I can almost believe that. I'd never seen such clean and pristine machines before. They were €15 each so I bought both.

I haven't had much time to play with them, but I tested one. It "sort of" works, meaning that nothing is broken or jammed, but all the lubricant has obviously "gummed up". At first the machine wouldn't turn at all; I helped it a bit and, little by little, the old grease "loosened up" and now the machine works; but there is still too much friction, and some things still don't work if I don't "help" the mechanism (i.e. the digit position drum).

I'd like to restore at least one to full working condition. I have all the technical manuals. I know it has to be cleaned and re-lubricated. But I've been unable to find many resources online. To clean it, I've read I can use isopropyl alcohol or "white petrol". But to lubricate it again, is where I'm confused. According to the manuals, you're supposed to use 4 different lubricants, from a thick grease for the power gears, to a very light oil similar to what's used in sewing machines for all the more delicate joints.
I'm wondering if, with modern lubricant technology, there is something I can use to make things simpler. My budget is quite limited, so I can't buy exotic stuff, but I want to avoid damaging something. Which means I don't want to disassemble the mechanisms, since I wouldn't have the tools or knowledge to reassemble and recalibrate everything.
Can you help me or point me in the right direction? Thanks!

Cristian

[DD]

Find some watchmaker in your area.

The use few kinds od lubricants.

Or... - dont use any lubricants.

If you will  use this machines ones a year - they should work.

--
You received this message because you are subscribed to the Google Groups "OldCalculatorForum" group.
To unsubscribe from this group and stop receiving emails from it, send an email to oldcalculatorfo...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/oldcalculatorforum/f810231a-52d4-437e-81fa-7b1aa4917646n%40googlegroups.com.

[JRespler@superlink.net JAY RESPLER]

I serviced D24 for Olivetti in New York and then became their agency in New Jersey.

I only used 2 lubricants. Grease for gears, very light oil for other moving parts and the rails that parts moved across.

I don't think I have any more D24 manuals, but I do have manuals for many other Olivetti machines. Also some ad literature.

All available  for sale if anyone wants.

Jay Respler
Advanced Business Machines Co.
JRes...@superlink.net
Monroe Township, New Jersey

---

--

[more...@gmail.com]

Hello!
I like mechanical calculators, so this is common situation for me.
In such cases I usually use common sprayer, filled with  mix of kerosene and medical vaseline oil: I simply spray this mix over all the mechanism and wait a day for infiltrating in all joints.
This is absolutely barbarian and wrong method, but it works for me over the last twenty years.
There are many aerosol cans with ready-to-use penetrating liquid lubricant, I think, they are fine too. You just should keep in your mind, that it have to be exactly the liquid lubricant, not just a drying liquid like WD40 or penetrating solid lubricant like lithol. 

[Antonio]

Buongiorno, ti scrivo in italiano perché vivo in Italia.

Questi meccanismi vanno lavati con una miscela di BENZINA AVIO + 3% OLIO DI VASELINA. Poi asciugati.

Basta, non serve fare altro.

Cordiali saluti.

Antonio Gobetti

--

[Cristian Arezzini]

Thank you for all the insights. So if I understad correctly, the idea of the mixture of solvent + vaseline oil, is that the solvent removes the old lubricant, and then evaporates, leaving the vaseline behind? How long will the vaseline last, is it stable or will it need reapplying regularly?

[Cristian Arezzini]

Grazie! Ho risposto a tutti in inglese perché potrebbe tornare utile anche ad altri. Adesso provo a cercare la benzina avio e faccio una prova... Magari sugli ingranaggi di potenza metto un po' di grasso al litio, che ne pensi?

You received this message because you are subscribed to a topic in the Google Groups "OldCalculatorForum" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/oldcalculatorforum/lJyb2hG94G4/unsubscribe.
To unsubscribe from this group and all its topics, send an email to oldcalculatorfo...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/oldcalculatorforum/CACSjzB9T4U5i08B9xSSqU6GD6hkhSR8s9e0iDcGQnjz%2BrUNLiw%40mail.gmail.com.

[Antonio]

Questa è la procedura di pulizia e lubrificazione che facevano i laboratori di assistenza Olivetti.

Dura per anni fino a che la macchina torna a sporcarsi.

Cordiali saluti.

Antonio 

To view this discussion visit https://groups.google.com/d/msgid/oldcalculatorforum/39a93093-5c72-499e-b1da-db916fc34060n%40googlegroups.com.

[Antonio]

Attenzione che la miscela non vada sui componenti ellettrici.

[more...@gmail.com]

Grazie per le informazioni, sembrano molto interessanti. Potrei usare il cherosene al posto della benzina? Questo sembra rendere la procedura meno pericolosa per gli incendi. 

Thank you for the information, it looks very interesting. Could I use kerosene instead benzine? This seems to make the procedure less fire-hazardous.

[Antonio]

No. Deve essere benzina avio.

Non credo si possa usare il kerosene.

Saluti

Antonio

To view this discussion visit https://groups.google.com/d/msgid/oldcalculatorforum/227fa0f2-31fa-4def-86e6-c1daf1c61050n%40googlegroups.com.

[more...@gmail.com]

Grazie per il consiglio.

[JRespler@superlink.net JAY RESPLER]

To clean out old sticky rails and print wheels, we used ordinary household alcohol.

Jay Respler
Advanced Business Machines Co.
JRes...@superlink.net
Monroe Township, New Jersey

---

From: "Cristian Arezzini" <macav...@gmail.com>
To: "OldCalculatorForum" <oldcalcul...@googlegroups.com>

To view this discussion visit https://groups.google.com/d/msgid/oldcalculatorforum/39a93093-5c72-499e-b1da-db916fc34060n%40googlegroups.com.

[Nigel T]

Has anyone had experience of using 'Super Lube' synthetic oil with PTFE to re-lubricate a mechanical calculator? - e.g. https://www.walmart.com/ip/Super-Lube-Multi-Purpose-Synthetic-Oil-with-Syncolon-PTFE-ISO-100-150/21074879

I am not sure what the synthetic oil is but on the pack that I have it says "synthetic lubricant that outperforms and outlasts petroleum based lubricants".  What happens to the lubricant over time?   I suppose it does evaporate, but does it thicken?  If it evaporates then perhaps the remaining PTFE still provides sufficient lubrication.

[Cristian Arezzini]

I couldn't find "benzina avio" locally. I found "Solvente AVIO" (composition: "Hydrocarbons, C6, Isoalkanes, <5% N-Exane, metyl acetate") and "Benzina rettificata" ("metil-pentane"). Both are advertised as very pure stain removers and degreasers for mechanisms. Is any of these equivalent to "benzina avio"?
Also, should I mix it with Vaseline oil 50-50? Mixing them together, does the solvent not damage the oil molecules? Wouldn't it be better to use the solvent first and the oil after?

[more...@gmail.com]

>  does the solvent not damage the oil molecules?

No, Vaseline oil is very stable (and good by this), so it would not be damaged.

> Wouldn't it be better to use the solvent first and the oil after?

The idea of the mix is that the mix is very liquid and fluid, so it would infiltrate to any place of the machine and dilute of old "dried" lubricant. Than the solvent will evaporate, but the oil from the mix will stay on place and will lubricate it.

By the way, Antonio said before about 3%  Vaseline oil.
I use 30-50%, but I spray it. Probably it is to big concentration for soaking.

[Antonio]

Ok, credo che la benzina sia giusta.

Mescolare con il 3% di olio di vaselina ( 100 benzina + 3 olio vaselina).

Serve per pulire delicatamente con un pennello i meccanismi e contemporaneamente oliarli. 

Basta un leggerissimo strato di vaselina per ungerli e fare si che non si arruginiscano. 

Non usare la miscela su parti elettriche o sui rulli di gomma.

Un cordiale saluto.

Antonio

Antonio

Il Mar 4 Feb 2025, 19:22 Cristian Arezzini <macav...@gmail.com> ha scritto:

I couldn't find "benzina avio" locally. I found "Solvente AVIO" (composition: "Hydrocarbons, C6, Isoalkanes, <5% N-Exane, metyl acetate") and "Benzina rettificata" ("metil-pentane"). Both are advertised as very pure stain removers and degreasers for mechanisms. Is any of these equivalent to "benzina avio"?
Also, should I mix it with Vaseline oil 50-50? Mixing them together, does the solvent not damage the oil molecules? Wouldn't it be better to use the solvent first and the oil after?

--
You received this message because you are subscribed to the Google Groups "OldCalculatorForum" group.
To unsubscribe from this group and stop receiving emails from it, send an email to oldcalculatorfo...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/oldcalculatorforum/c42059df-4a3c-4e2e-9703-8d5ced6f56a7n%40googlegroups.com.

[Nicolò Geretto]

Ciao!

Io personalmente per le mie macchine uso Sgrassatore Fulcron a base di solvente per sbloccarle:

https://amzn.eu/d/g8bSPFZ

Una volta sbloccate, olio di vaselina spray e funzionano a tempo indeterminato!

Se hai bisogno scrivimi pure, da appassionato ho messo apposto almeno una decina di macchine... 

--

You received this message because you are subscribed to the Google Groups "OldCalculatorForum" group.
To unsubscribe from this group and stop receiving emails from it, send an email to oldcalculatorfo...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/oldcalculatorforum/f810231a-52d4-437e-81fa-7b1aa4917646n%40googlegroups.com.

[Rich Walker]

Hi, I am looking for a technical service manual for the Olivetti Divisumma 24, you say you have all the manuals, where can I get them? If you have them digitally, can you send them to me or would it be possible to scan them? I also have 2 Divisumma 24s, one does not work and the other one works but I made the mistake of putting it in an ultrasonic cleaner with ammonia and the paint has peeled off the round white indexing drum with the red symbols. I can't get it apart to repair, it's complicated. Help, Rich.

[Rich Walker]

Hi Cristian, I have one Olivetti Divisumma 24 that is jammed so I bought another one that sort of worked, it seemed sticky so I cleaned it in an ultrasonic cleaner with distilled water, 1% ammonia and some dish-washing liquid. I then blew it dry with compressed air and then with a hair dryer, then I sprayed it all with some "Liquid Bearings" Synthetic Oil, they say don't use WD-40 or 3in1 oil. Now it seems to work fine, no hangups. Only problem is that the paint all flaked off and now I have to fix that. I used these machines in my first job out of school in 1967, so I have a soft spot for them. Good luck with yours. Rich.

On Sunday, February 2, 2025 at 4:02:26 PM UTC-5 macav...@gmail.com wrote:

[machinea...@wanadoo.fr]

Bonjour

 

As-tu regardé sur le site www.machineacalculer.fr ?

Rubrique Divers

 

 

Christophe

 

De : oldcalcul...@googlegroups.com <oldcalcul...@googlegroups.com> De la part de Rich Walker
Envoyé : vendredi 4 avril 2025 02:20
À : OldCalculatorForum <oldcalcul...@googlegroups.com>
Objet : [oldcalculatorforum] Re: Two new-old-stock Olivetti Divisumma 24

--

You received this message because you are subscribed to the Google Groups "OldCalculatorForum" group.
To unsubscribe from this group and stop receiving emails from it, send an email to oldcalculatorfo...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/oldcalculatorforum/0667d985-47c8-444d-96c4-bfd2ed4a854bn%40googlegroups.com.

[Cristian Arezzini]

Hi, I don't remember now where I got the manuals. But they're digital, as soon as I get back home I can send them

--
You received this message because you are subscribed to a topic in the Google Groups "OldCalculatorForum" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/oldcalculatorforum/lJyb2hG94G4/unsubscribe.
To unsubscribe from this group and all its topics, send an email to oldcalculatorfo...@googlegroups.com.

[Rich Walker]

Hi Cristian, please send me the digital copies of the Olivetti Divisumma 25 manuals that you have to: richrw...@gmail.com.

Thanks so much, I have started disassembling my calculator and I need help.

Rich.

[mg]

Hi Rich,

There are several service manuals available for download on archive.org that should be helpful to you.

This is the detailed factory service manual for the Tetractys, but it also covers the Divisumma 24: https://archive.org/details/mc-24-stac-eng

Here is a troubleshooting and fault finding manual for a number of machines, including the Divisumma 24: https://archive.org/details/olivetti-mc-20-mc-23-mc-24-mc-26-fault-repair-guide

Best of luck with the repair of your Divisumma!

Mark

[Rich Walker]

Hi Mark,

Thank you very much for these links, it looks like the documents will be very useful to me.

I have 2 Olivetti Divisumma 24s, One is jammed and does not work, the other works, now that I cleaned it in an ultrasonic bath with 1% ammonia and oiled it with "Liquid Bearings".

The ammonia was a bad mistake because it stripped off all the paint so now the rotary indicator with red symbols on a white background is now mostly bare metal.

It looks like it will be a long tedious process to get them both restored.

It took me a few days to extract the rotary indicator from the stuck machine so I can swap it out, but I am hesitant to have both calculators torn apart without good documentation for reassembly.

I also have a working Monroe 1610 nixie tube scientific calculator, a Facit C1-13 and about 17 different HP RPN calculators.

Thanks for your help.

Rich.

Rich Walker
1091 Edinger Road
Urbana, OH 43078
walk...@gmail.com

Cell: 937-869-2673

You received this message because you are subscribed to the Google Groups "OldCalculatorForum" group.

To unsubscribe from this group and stop receiving emails from it, send an email to oldcalculatorfo...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/oldcalculatorforum/7169169b-ec32-46ae-b5cf-9412aadb0547n%40googlegroups.com.