Retro Tech - Olivetti Prima 20 Adding Machine - Part 2, Demonstration

[@Faithique]

Thank you for making this video. I purchased an Olivetti Summa Quanta 20R and had no idea how to use it or even how to load the paper. I found your videos helpful. Thank you.😀

[@GrumpyTim]

Excellent Faithique, they're such interesting machines to use, and that period styling is a thing of beauty.

[@samni9068]

I recently bought one from an auction and I’m so glad you have a video on how to use it!! Thank you!!

[@GrumpyTim]

Excellent, well done, they're a fantastic machine. At some point I'll do a video showing how to do division on that machine - it's a bit long winded but kind of fun all the same.

[@tsr207]

As an ex Olivetti engineer I found this fascinating - the SP20 was ideal for the small office environment - and sold well in countries that did not have a stable power supply !

[@GrumpyTim]

Hi John, how exciting to have been an Olivetti engineer - if I could go back in time I'd rather like that job. The Olivetti adding machines do seem to be very popular these days (and the typewriters for that matter), not such a surprise because they look fantastic.

[@tsr207]

@@GrumpyTim O would say that the Olivetti engineers thought the company designed the covers the tried to fit the mechanics inside !

[@tsr207]

@@GrumpyTim Taking the handle off before the start of the removal sequence makes the casing move around enough to ease the case off - putting the total button up is also suggested. The Summa 19 was impossible to disassemble without breaking the clips !

[@GrumpyTim]

Haha, they probably weren't the first company to do something like that - great visual appeal, but not so great for the people who had to work on them and fix them!!!

[@GrumpyTim]

I must admit, I was kind of surprised how the case came off - having to ease it past parts of the mechanism is always a recipe for future breakage. Sounds like the Summa 19 was even worse from what you say!!!!

[@simonuden8450]

You guys are obviously very young. As a 15 year old, in 1972, I was illegally working on a petrol station forecourt in the UK (I think the minimum age is 18 for dispensing fuel), and used to have to cash up at the end of the shift using one of these. It was all manual, not just the calculator, but taking readings off the petrol pumps at the end of the shift and subtracting the readings from the previous shift end, then working out the value of each grade of petrol (we had 5-star in those days), and then subtracting the float. The calculation printout had to go in the aluminium container with the notes and coins that went into the floor safe before locking up and leaving at night. Some nights I was there for hours getting it all to balance, but I was always impressed by the machine, and now I've bought one for myself. It reminds me just how much simpler modern digital electronics has made things. Things that were very complex before, but we didn't think anything of it, because we didn't know what was coming around the corner.

[@GrumpyTim]

Wow, that sounds awesome Simon, I know what you mean about modern systems being much simpler, but we now have the tedious issue of endless system updates to contend with instead!!! There is something rather fun about using old machines like this to do your calculations, particularly if you only have to use it for fun rather than an actual job. I kind of like the idea of working on a forecourt in the 70s - I love the petrol pumps of that era - most people seem to go for the earlier pumps in their man caves, but I'd love to have one from the 70s - not that I'll be getting one any time soon, as the prices just keep going skywards!!! Thanks for the excellent comment.

[@simonuden8450]

@@GrumpyTim Better still, the forecourt had a workshop behind it, and a small showroom. It was a satellite of the local main dealer for Citroen. The whole place reeked of used engine oil and stale petrol - a smell you rarely come across these days. At that time, my dad was working as an engineer for Rolls-Royce Engines, working on turbo jets. He never brought his work home with him, because it was too sensitive, and he never discussed it, but on one occasion when he was due to fly over to France to meet with Snecma, he brought a Curta calculator home with him. I was fascinated by it, and my memory was of a machine far more complicated than the ones I've seen recently. I don't know how much they cost, but my dad, despite being a head of department, was required to sign the thing out before leaving the office with it.

[@GrumpyTim]

Ah yes, the old style garage/workshop used to have an amazing smell - there are probably a few of them left dotted around. I used to work in the printing industry, and in the early days the smell of ink and gear oil as it leaked out of the old machines was fantastic. On the more modern presses they used IPA (Isopropanol) in the damping systems and the factory kind of had a permanent haze of alcohol aroma - it could get a bit much day in, day out. I guess the Curta was always pretty special - certainly the prices now are colossal compared to the bigger, desk based machines. I've never seen a Curta in the flesh - it would be nice to have a play with one, but I wouldn't part with that sort of money to get one.

[@drickyar]

Thank you!

[@GrumpyTim]

Cheers Ricky, you're welcome.

[@jeffduros4220]

Tim, Well Done Y-Tube Clip. Question for the group: How do I adjust my Olivettis print wheel so I’m able to see the print better. A new ribbon was put in but my printed numbers are faded you can barely see them. The print keys just don’t press hard enough to get a good black or red print. I would appreciate any feedback you could give me. Thank you

[@GrumpyTim]

Hi Jeff, the general opinion is that these machines originally came with a heavy inked ribbon, because the numbers print with far less force than a typewriter. All the new typewriter ribbons I've tried have a fairly light inking, fine for typewriters but not so good for some adding machines. Also, the platen roller would have had some give when it was new, allowing the printing number wheel to imbed itself slightly into the paper and roller, which would also give a better print. Finally, it's not so unlikely that, if the platen roller has gone hard, it's also shrunk a bit in the process. There is of course the possibility that your number wheels are sticking a bit as they fly towards the platen roller, or that the springs have become weak with age. I did find some seemingly better inked ribbons that were sold for my Adler 1214P - although I bought them a couple of years ago, so the new ones may just be the same as the standard typewriter ribbons now, but you could get one and rewind it onto your Olivetti reels. Those ribbons came from electropapa_uk on ebay and were listed as "Ribbon nylon black-red for Triumph-Adler 1214 P, 1216 P, 1217 P, 1218 P". I did also consider using a suitable sized heat shrink tube on the platen roller to boost it's size and give it a little compliance - some heat shrink tube is hard and glossy but there is also stuff that remains slightly rubbery and velvety - that would be the stuff to go for, in a size for wrapping nicad batteries and the like. I haven't done any research into sourcing this, and it's only a theory that it might help - but so long as it was done carefully, applying the heat evenly and not from a naked flame such as a blowtorch (a hot air gun is what you want), it could be reversed by simply removing the heat shrink if it didn't work.

[@colinslack2555]

Brilliant well made You Tube clip Tim. I was fortunate last week to buy a Olivetti Prima 20 (mine has no zero keys but decimal points) and it seems to work well , aside for the odd sticking number. with more use it is working better. Interested to know where to buy the paper rolls please - most seem to be 57mm wide not 60mm and is often thermal paper?

[@GrumpyTim]

Cheers Colin, glad you've got yourself a working machine, they're lots of fun. For the paper rolls I tend to search on ebay - we use 57mm paper in the Olivetti and it seems to work ok. As you say, they're more often thermal rolls, which do work but the non thermal are preferable. Generally you seem to have to buy a box full of rolls, but they should be relatively cheap. I needed a wider roll for my Precisa adding machine (70mm) - they took more finding - I got those from elepos.com, and they're non thermal rolls at that.

[@colinslack2555]

@@GrumpyTim Many thanks for your quick reply, I will look into the replacement paper rolls. I look forward to many hours of calculation , it amazes me how it all works

[@omeldcruise]

Hi there! I have the same device but I cannot make it work, since the hammer mechanism passes very far from the rubber roller and I cannot find a way to regulate that distance, it is about 1 millimeter what I should adjust. -_- Do you happen to have more information about the breakdown of the mechanism?

[@GrumpyTim]

Hi Diego, the Olivetti that appeared in my video actually belongs to someone else (I was just fixing it for them), but I'll be seeing them at the weekend so I'll take a look at the machine and refresh my memory on the mechanism, then I'll get back to you.

[@GrumpyTim]

Hi again Diego, I was just having a look at the Olivetti - were you saying that your hammers only move about 1 millimeter, or that they stop short of the rubber roller by about 1 millimeter? Looking at the one here, it I enter a number and pull the handle towards me and then very slowly release the handle, initially the hammers are released and they move about 1 millimeter but their ends are held by a metal bar (the metal bar sits just to the left of the total/subtotal selector switch). Then, as I carry on releasing the handle slowly, the number racks raise to dial the current number onto the number wheels, and then after this the metal bar that is holding the ends of the hammers is raised, allowing the spring loaded hammers to fire the wheels against the rubber roller. After that, the wheels are retracted back into their rest position, at the same time the racks lower back down, adding the number into the accumulator. If you can describe what your machine is doing during this process, I can see if I can figure out where the problem might be.

[@Retroscoop]

Very nice looking Design Museum-ish machine, but at the same time somewhat complex compared to a much heavier electro-mechanical Burroughs Ten Key.... Of course, the storage room needed is only half, and the weight difference is considerable. Saw a Prima 20 on a flea market last year, only 10 Euro, but unfortunately without the lever, so I didn't take it in the end....

[@GrumpyTim]

Hi Retroscoop, they're definitely an item where style was an important part of the design brief, and I like them for that. The different approaches taken by manufacturers to essentially do exactly the same thing is what I like most about old mechanical calculators and so on. Good call not to buy the Prima 20 without a handle - you'd have probably had to buy another one to get hold of the handle unless you were either lucky and found just a handle, or you were pretty good at fabricating stuff and made one.

[@BensWorkshop]

That must have taken quite some thought to come up with the mechanics for that.

[@GrumpyTim]

There are elements of the design that are pretty similar to the Burroughs adding machine I featured in another video (the accumulator system is more or less the same) but the Olivetti has far more functionality and is in a much smaller package so the designers did a pretty good job to pack it all in.

[@IlFerroviere]

You did not show what the ½ key does!😂 Also, this machine can show negative subtotals by printing the - sign on the right of the rhombus or asterisc (like *-). Also, the subtraction works differently from what you told: it rotates by 180° the whole accumulator! It's a fantastic machine, you can even do percentuals, divisions and with a little work even square roots!

[@GrumpyTim]

Coo I'd love to do square roots on it - I can do them to a certain extent on a pinwheel calculator but I hadn't thought about doing them on the Olivetti. Can't believe I forgot to show the 1/2 key, oops!!!! Thanks for the info Nicolo

[@GrumpyTim]

Hi Nicolo - I just watched your video dividing 355 by 113 - my Prima 20 doesn't have the backspace (pull down) option on the clear lever so to move the indicator to the right I have to clear the input and re-enter it with one less zero but apart from that it worked - brilliant, very excited about that, thanks :-)

[@brunopacifico4979]

Actually, I think it is simpler to do an inverted division, in which I insert a negative number in the accumulator and make a series of additions!

[@IlFerroviere]

@@brunopacifico4979 How I didn't think about that!!! You're right!

[@brunopacifico4979]

@@IlFerroviere I will publish videos of these and other discoveries I made in my Suma Prima 20. Unfortunately I do not speak English very well, but I will try to find some way to subtitle my videos so that non-speakers of my language, Portuguese, understand. They will be my first videos on KZbin, so they will have poor quality. I am very, very happy to have helped you !!!

[@andyvan5692]

this may be an adding machine, but if it only does currency, then why not call it a cash register?

[@GrumpyTim]

Hi Andy, as far as I'm aware, a cash register typically has the drawer (or some other receptacle) for the money, whereas this machine would usually be used in the back office to add up the accounts. Also, you can ignore the decimal point and just use it to add numbers as you would on any machine - they just included the decimal because adding up financial accounts was a fairly common use of the machine.