 Hello, I'm Rob, and these are Rob's hands, and what Rob and Rob's hands are going to do is take apart this mechanical calculator. The calculator was made by the Monroe Calculator Company somewhere between 1921 and 1928, so this is about 90 years old. You can get these off eBay for $50 or $100 in various states of disrepair. So, for example, this crank, which is supposed to clear out the digits on the carriage, actually does not work. This is kind of really hard to turn, so obviously this needs some care. The last time these were probably used was, say, 1950 to 1960, and then they had digital calculators, so they fell out of repair. They haven't been maintained, so they're probably really dirty and grody inside. So what we're going to do is we're going to take this apart. I'm going to make a whole set of videos. Maybe they're going to be half an hour or 45 minutes each or so of just taking this apart, cleaning it, and then putting it back together and hoping that it works. So let's just get started. To begin, we need to take the carriage off, that's this top part. It just sort of hinges up. You have to pull back on these tabs. There's another tab over here, but it's apparently broken, which is okay because I might be able to replace it by maybe, I don't know, modeling it in SolidWorks and sending it out to get 3D printed. Anyway, you pull this back and there's this hinge that runs or an axle that actually runs along the back, which allows this thing to hinge. So what we need to do is take that hinge out or axle. So in terms of orientation, this is the right side and this is the left side, so with the calculator facing me. Okay, so before we actually unscrew anything, let me show you all the tools that I've gathered that we're going to use. So the first thing, and I think one of the most important things is a screw checker. What this does is that you can screw a screw into these threaded holes and it will basically tell you what size screw you have. This is an imperial screw checker because these machines were made in the United States. It only uses imperial screws, no metrics, so a screw checker. We also have a series of screwdrivers. So we have a big screwdriver, flathead, and a small screwdriver with various heads. We also have a digital calipers. These are useful for measuring parts. We have a dental pick and a 1mm flathead screwdriver. These are useful for poking and prying at small parts. We have a whole bunch of bags. These are presto closed bags and these are really, really useful. You have to have a lot of them because as you pull off each part, you want to put it into a bag so that, A, it doesn't roll away and get lost. And B, it keeps all the related parts together so that when you put it back together, you'll know where all the parts came from. This is kind of like the world's biggest 3D puzzle without any instructions. So you have to make up your own instructions as you go along. I also have needle nose pliers, the thinner and the longer the better, and of course a Sharpie to mark your bags. So what I also do is I have a notebook that I use to sort of document where all these parts came from, where they go, so that I know how to put them back together again. I augment this by taking photos of every part before it comes off. And I can also point at the part using a dental pick or something to know which part I'm actually taking off when I look at the photo later. And then a photo of the thing after I've taken the part off. So this way I'm absolutely sure that I know what sequence I took everything off in so that I can just reverse the sequence and put everything back together again in the right order. Okay, so which reminds me, I don't know why it reminds me but let me move the camera over a little bit so that we can see the thing. I'm just going to set a timer for, let's call it 45 minutes at this point. So, okay Google, set a timer for 45 minutes. So that's convenient. Setting timer. Yes, okay, setting timer. Do we start the timer? Yes, let's start the timer. Okay, so 45 minutes on the clock. Okay, so let's go ahead and since I'm taking a video I don't actually need the notebook or to take photos. The video will serve as a record. So here we go. So on the left side there is this screw over here and that screw holds in that long axle that runs along the side. So there's also, if you look at the other side, this thing weighs about 50 or 60 pounds by the way. If you look at the other side there's also this screw over here. That's actually not a screw. That's actually just a slot in the other end of the axle. And it's useful if you try to unscrew the left side and it just keeps turning you can put a screwdriver into this slot to prevent it from turning. So I don't think I'll need that on this. So I'm just going to take the large screwdriver and unscrew. Okay. Now I'm going to, every time I take a screw off I'm going to measure it to make sure I know what size it is. So it looks like this is a number 836. So 836. I don't know if you can see that. So number 836 and then I take the calipers and using the depth gauge on the calipers I'm going to measure from the bottom of the threads to the bottom of the head. And that's going to be the length of the screw. And I'm getting .290 or .282, something like that. It doesn't really matter. That's obviously more than a quarter of an inch and less than 3 eighths of an inch. So I don't know if they actually manufactured their own screws or if they bought them. So maybe the lengths aren't quite accurate or they didn't really care, didn't really matter. Okay, so I just bagged that screw. I labeled the bag, bag 1. So now I can set that aside. It's also probably a good idea to get a cardboard box and put all the bags in that cardboard box so that the bags themselves don't get lost. So now we can hinge the carriage back and we can just reach inside and pull and slide that axle out. There we go. Axle carriage. So we can set the axle and the carriage aside. And there's also going to be a spring that came off of the axle. And the purpose of that spring is it sat right over here and it prevented the carriage from banging against this part. So that's a loose part so I'm going to stick it in bag 1. Okay, so that is that. So the next thing that we're going to do is we are going to remove this crank because we're going to start taking off the sides. So to remove the crank it's pretty simple. There's this lever over here and if you press it towards you, you can just pull the crank out. So we're going to set the crank aside. When they put these machines together, I read this article when these machines first came out. They actually hooked up an electric motor here and then they just had the thing adding constantly for hours just to do quality assurance. Which is kind of neat. Okay, so we're going to take off the right side of the machine. So there are two screws here and there's another screw here and another one down there and two screws down here. So let's go ahead and take the screwdriver. And just as a general note, when you decide what size of head you want to use, don't use a head that's too small for the screw because then you just end up ruining the head of your screwdriver that is. And if you get one that's too big that you have to sort of jam it in, that just ruins the screw itself. So just a little note. So okay, let's go ahead and remove this screw. Now we're going to measure it. So is it four? No. It's not five. It's six. It's 640. Okay, so it's 640 and the size is .442 or so. So that will go in bag one. Now let's take off this other screw, measure it. It's also 640. Measure at the length. It's also about .443. So it's basically the same size as this other screw was. So that goes in bag one. We can remove the front two screws now. This is a shorter screw. Oh no, don't lose the screws. All right. And it's a number 640 also. And the size is .252. So basically it's a quarter of an inch and that goes in bag one. Next screw. It's also 640 and it's 245. 245, 248, whatever. I don't think it really matters down to the thousandth of an inch. Okay, let's remove the bottom screw. Here's a useful tip. Whenever you're unscrewing something that will eventually, if all the screws are removed, fall down due to gravity, unscrew the bottom screws first. So this is also number 640, 251. So that goes in bag one. And the last screw is also 640 and 252. All right. And now we can remove the side. All right. So what have we got? We have some kind of material here that's not plastic and it's not rubber. It's not cloth. It's kind of in between. It seems a bit light, but I'm pretty sure it's steel. And then there are these nuts. And on the other side, these are not screws, but they're nuts. So clearly whatever those are, they're threaded. And then I guess this thing would come out. I'm going to leave these parts on just to keep them together as an assembly. And then maybe later on, if we want to actually go through and clean everything thoroughly or investigate everything, we can take it apart later. So I'm just going to set this aside. So here's the inside. Wow. That's clean. That's the cleanest that I've ever seen one of these machines. There is actually no evidence whatsoever of oil or grease or anything on this machine. It's as if it was put together and never actually used. That's really, really weird. But that kind of explains why everything is really, really hard to turn because it's got no lubrication. So that's kind of interesting. It'll certainly save my hands from getting really, really dirty. If you're really concerned about getting all this dirt ground into your hands, use some latex gloves. So anyway, that's nice. Let's take apart the other side. Actually, what we can do is, because it looks like the back is only held on by these two screws, let's take the back off first. Screw driver. And let's take the bottom screw out. It's another little screw. It too is a number 640 screw. And it is 247. I guess all those quarter of an inch screws roughly are interchangeable, which is always a nice thing. And the top screw, also a little screw, predictably it is a number 640. It is .245. Or as close to a quarter of an inch as doesn't matter. Now we can pull this out. There's the logo of the Monroe Calculating Machine Company, New York, which is actually kind of funny because they actually were headquartered out of Orange, New Jersey. But hey, you know, whatever they want to say. By the way, the Monroe Calculating Machine Company still exists today. Let me just pull this up on my computer. I have a bunch of notes. Yeah, I'll just let that boot up. But anyway, okay, so it also looks like we've got some things here. We've got a piece of cloth for some reason. More of this material, rivety looking things. So that's the back. I'll set that aside. So yeah, today the Monroe Calculating Machine Company is called the Monroe Systems for Business. They actually still make calculators. They make obviously digital ones now. They also make shredders. They also have toner and ink cartridges. And for some reason they still make typewriters. I didn't know that anybody actually used typewriters today, but they make them. So anyway, here's the back. This funny twirly thing. Kind of a little, I don't know, Helix looking thing. That's actually a ripple carry mechanism. And if you ever have the chance to go to the Computer History Museum in Mountain View, California, which is where I am right now, I'm not in the Computer History Museum. I'm in Mountain View. Go see the difference engine that they have. It's not an actual Babbage built difference engine because he never actually built one, but it's basically a reproduction or replica or whatever built from his plans. And it has a mechanism kind of like this for the carry, which is kind of cool. All right. Let's go ahead and now take the left side off. So there should only be one. There are only two screws remaining. So let's take those off. Screw out. And it's a long screw. 640.441. Bag it. And the other screw over here. We can now unscrew. Also 640.442. Bag it. Oh, right. There are two other screws on the front, which we can remove. Do the bottom one first. It's a short one. 640.252. And the top one, it's also short, probably the same, but we'll measure it just to make sure. 640.250. Bag one. Okay, now it just comes off. It's got some dust in it. But basically it's the same thing as the other one. There are these rivety kind of things with nuts on them, holding down this material. So that'll go on the side. Okay. And what have we revealed? More levers and things and thingalings. It's got a bell. Ding, ding. Okay, that's quite enough of that. Okay, and then there's this front part. Now the front part is, it comes off, but it's being blocked by this crank over here. This crank is actually used to move the carriage over. One position, one position, back and forth. And it's basically held on by a screw. Now on all the machines that I've seen, except of course for this one, which appears to be in pristine, unused condition, there's a screw here, and that screw is often held by rust, effectively. And it's really difficult to take it off unless you use a lot of penetrating lubricant. Don't use WD-40. Use something like liquid wrench. But I'm going to probably be able to just, to just unscrew this. Okay. It's a little screw. Is it a 448? I think so. It's certainly not smaller than that. It's certainly not bigger than that. It's definitely a 448. And in terms of size, it is quarter inch. Bag one. Now I can remove the crank and bag it. And there we go. So the thing about, like, damage like this and the logo is off, if you're making a showpiece, you can just repaint it and put on another logo, I guess. But if you're planning on selling things as an antique, you never ever fix the outside damage because that just lowers the value. Because then it doesn't look like an antique, I guess. So you can set the front aside. And there's a tiny piece over here which comes off also. So that can go in bag one. And there's the front. So, well, that's interesting. So if you see over here, on the bottom piece is stamped the model number, K161, and the serial number, 777. I'm going to have to peer at this closely. It looks like 777.339, I think. Okay. So it's always a good idea to put the serial number on the bags. 777.339. Pretty sure that was a 3. Yeah. 777.339. Because if you're like me, you're taking apart multiple of these at the same time. So, okay. So we are going to close off bag one, set it aside. The next step, I think, is going to be maybe, it's either going to be removing the top or the bottom plate. I'm not quite sure. So what I'm going to do is I'm going to stop the video right now. We have been recording for about 20 minutes or so. I guess that's okay for the first video. I need to take a break, and I will be back in the next video taking off either the top or the bottom. You can make a guess. So, bye-bye for now.