 Hello, this is the seventh video in the series of taking apart a Monroe Model K mechanical calculator. So we had gotten to separating these two frames. There's a couple of things I wanted to show. The first thing is on this frame, which is the frame without the gears, and therefore it's the left side, there is the serial number and model number, K161 77339. There is another K series, KA that I'm taking apart, which is the automatic version, which has a serial number in the 143,000s. So one way of looking at that is if they did actually increase the serial number by one every time they put one together, that would mean that there is a little less than 70,000 machines separating this from the other one that I'm taking apart. What I want to do is I want to show you the equivalent side of the one that I'm taking apart, which is KA 163 143032. So just as a comparison, you can see that. So there's a lot of similarities and a lot of differences. For example, this post is in the same place. This hole is for that axle, it's in the same place. There are these two holes here which are the same, a hole here and a hole here. There's a pin here, actually that's a screw, which I haven't taken off yet, so that's that, this and this. So this sort of section is the same. There's a post here and a post here, this post is a little longer. A set of three holes here, a set of three holes here, a bushing, a bushing, more bushings. Actually it's pretty similar, isn't it? Even on this side, there are the three holes here and the three holes here. So these are actually kind of similar and in fact that almost goes so far as to say they're virtually identical. There are some obvious differences. This says 679A, this says K679A, so that's that. Let's take a look at the other side. So this one says K678, looks like a B or maybe a D. This is the equivalent and it would be like this. This one says 678D, so maybe that's D as well. But that's obviously where this gear sits and other than that, it looks pretty much the same. So aside from a slightly different style, like for example in the one that we're taking apart, this section is totally filled in while this section is not. So this section here is sort of totally filled in while this section is not. So obviously they used different molds but essentially the same outcome. So let's go ahead and continue to take parts off of the right side. So I'm going to close off bag eight and I'm going to start a new bag nine to hold all the parts that we take off of this side. So bag nine. So the other possibility is that they started with the 70,000s during the first year that they made these and then continued so that 80,000 would be the next year and so on. Unfortunately that doesn't really help very much because if the first year was 19, what did I say, 1921 I think, that would be the 70,000s and then 1928 was the last year. So that would be seven years which means that they would be in the 140,000s. So that's consistent but whether it's true, who knows, 77339. Alright so let's go ahead and take this gear out now. So it's also got a retaining clip which we can probably remove in the same way. So I'll just hook one end, pull the other. Unfortunately my hand's in the way but it probably can't be helped. Maybe if I just had the right tool to do this. It removes the clip and let's see what have we got. Okay we've got a large washer and the washer outer diameter is .628 and it's thickness is .034. So that goes in bag nine. And then can we remove the gear? Well this gear is also just by itself is hard to move. So that indicates that whatever oil or whatever was used for this, it was really bad. So I'm just pulling this out, pulling it out and there we go. So there's the gear and there's this other part that turns. I think this is probably, well it's either press fit or it's essentially glued in by the oil. So we're just going to leave this as is. And I'm going to stick it in bag nine just so that if those parts do get loose they don't get lost. Yeah so this is the, wow it's sticky. Almost as if somebody used like vegetable oil which is a really bad stupid thing to do. Okay let's flip this around and now we can remove the retaining lever for the crank handle. So I'm just going to remove the spring from its post. Okay the spring is now removed from its post. Alright so this is also on a post which means that the spring can come off. So because of that I'm going to remove the spring and then I'm going to measure it. So I will measure its outer diameter. Measure its outer diameter which is 0.152. Measure its wire thickness 0.019. And I'm going to measure its length. So it looks like it's about 0.7, 0.71 or so. So that way if there's another spring I can differentiate the two. Okay so now we have this lever so is there a nut on the other side? No it's just a screw and because it's pretty loose that probably means that there's going to be one of those washers with a little shoulder on it that this lever can sit on. So I will just remove the screw. Well even this bit is too thick so I'm going to choose a thinner bit actually. Can my big screwdriver fit in? No. Okay so this is a little unfortunate because the bit that actually fits in here is the screw is actually wider than that bit so I just have to be really careful. So the problem again with using a thinner, well not a thinner bit but a narrower bit than the screw is that as you apply force you're going to need more torque to apply force to the screw in order to turn it. More torque than you would if you had a wider bit. Which means that it's easy to damage your screwdriver probably not so much the screw. So I'll get it approximately centered so that the torques are balanced out and then I will just turn. There we go. Now I can loosen it by hand. So I'm just going to very carefully remove the screw. Okay so there's the screw. Okay well there was no... Ah okay so the shoulder is actually integral to the screw. That's good to know. So the thing about screws like this they're basically custom and there was a thing called a screw machine and a screw machine was kind of like a sort of mechanically programmable lathe essentially. And what it would do is it would, you can go on YouTube and look for screw machines. There aren't really any of those anymore because nowadays we have CNC. But basically it would take a shaft of the material right and it would push it through and then it would have little cams with different cutting tools on them. So there would be one cutting tool here and then if it turned there would be another cutting tool and then it would turn again and there would be another cutting tool. And there would be a tool facing this way and another tool facing this way. So this would spin and then this tool would come in up to a certain point and it was all controlled by cams. It would come into a certain point and then it would move in order to do a cut and then the tool changer would change to another tool and then it would make another cut and eventually you would cut off the piece and then it would drop into a bin and then you get a piece like this that was unthreaded and didn't have a slot cut into it. And then the threading and the slot cutting would happen in a different operation. And that's how they automated making thousands of these. So that's what a screw machine was for. So anyway, there are the pieces. Oh, I didn't measure the screw. I should do that. I think this is too loose to be a 1032. It is an 836. Do not lose the screw. Oh no, where did it go? Well, now I have to crawl around on the floor like a baby until I find the screw. So let me just go do that. I think it went somewhere around here. Yeah, that's really bad. Don't drop screws. If you were working on a pocket watch and you dropped a screw, that's even worse. So I don't know where the screw went. I can't find it. It's obviously on the floor. How far did it roll? Okay, well, I'm going to have to find it later. So that's kind of unfortunate. So I'll just have to remember that there is a screw on the ground that I have to find. So we'll go in bag nine. Really, really bad to drop screws. So you saw it. I did it. I am the dumb one. Okay, let's turn this over and let's deal with this mechanism over here. It looks like the entire mechanism can come right out. This is just a pivot and it's actually just loose right over here. So there's nothing really holding any of this in except for these two screws. So I'm going to go ahead and unscrew those screws. I'm holding my hands well away from the edge now. 836 and 0.340 bag nine. And then we've got another screw to remove here. 836, 0.335. Okay, so now this whole mechanism should just lift right out. So parts are going to be loose. This part, this is the zero or the clear key. It is held in place with a retaining wire basically and a stop. So that's not going to come out. This on the other hand is going to come out certainly thus. So let's remove it and it actually sat in a pivot right here. So that's for something. So that'll go in bag nine. Then this can be removed I think somehow. Okay, so this one can now be removed. Now you notice that the difference is that this one has a square cutout and this one has a sort of funny shape cutout. So that comes out. And then I'm just going to leave the rest of the mechanism in place. So that's that mechanism. So all that will go in bag nine. Okay, let's see what else we've got. Okay, so we've got a screw here, a screw here and this standoff. There's a nut here and a nut here. So the standoff doesn't seem to have any nut. Let's remove that first. There is a washer. So the standoff is 1032. And the standoff, well this is the only standoff. So I don't really need to measure it. I'll stick it in bag nine. The washer itself is .375 outer diameter, .04 thickness. Inner diameter is .189. Bag that. Okay, so now let's deal with this screw and it's got a nut on it. So let's go ahead and loosen the nut. And then we can keep the screw with the nut and any other parts that happen to be attached to it. So there's the screw. I mean the nut. There's the screw. And I'm just going to put it together again in the right orientation because flipping this nut around is the wrong thing to do. So bag nine. And finally we've got this screw which is held on by this nut. Remove the nut. Loosen the nut. So there's the nut. There's a spring washer or a split washer. Split washer. Is this loose? Yes. It is loose and there is also yet another washer on it. So it goes screw, washer, frame, split washer, nut. I'm going to put these together again. Split washers are interesting. They're supposed to act like springs. In other words they're supposed to expand or have force that expands. So in this case it would push against the nut and the frame. And the idea behind that is that it would hold the parts firmly in the face of vibration. The idea being that if you tighten down on a nut that would be sort of the same force that you would get by compressing this spring. Now there's a lot of controversy about that if you look on the web. NASA has published a paper that basically says that once you compress these split washers so that they're flat they actually serve no purpose. They certainly don't grip the metal thus preventing rotation. So they definitely do not prevent rotation when they're fully compressed. There's another demonstration on YouTube that you can look for that shows a screw or a bolt with a nut and without a split washer and the same thing with a split washer. And then they vibrate the piece basically in the same way and it shows that the split washer actually does nothing to prevent loosening under vibration. So that's the big controversy today whether they're actually of any use whatsoever. If I were actually doing something today I would probably replace this with either a lock nut or a lock washer. Is this called a lock washer? I'm not sure. But it's a washer that has sort of this rough surface which sort of digs into the metal. Anyway, but I'm not a mechanical engineer so what the hell do I know? And that's it. The frame is now completely clear of parts. We can clean it up. We can maybe coat it with something that will prevent it from rusting because this is basically bare steel. It seems to have done a good job on its own not rusting. I mean I do see some discoloration that kind of looks like rust but I mean it's not completely crusted over with rust so either this was kept in a really good humidity free environment or maybe it's actually plated with something. I have a zinc plating kit that I wanted to experiment with. The idea behind zinc plating of ferrous parts is that the zinc acts as a sacrificial metal and it actually rusts first. It just forms a kind of a white powder so it protects the underlying iron from rusting. And in fact you don't have to even cover the entire part with zinc because rusting is actually an electronic phenomenon and of course in metals electrons move pretty freely. So just having bits of zinc plated onto the metal will actually prevent rust even on the parts that are not coated with zinc because the electron transfer will actually move between the zinc and the iron. But that's enough of that. So there we go. Let's see. It is about 25 minutes so what I'm going to do is I'm going to set this aside. I'm going to stop the video early because I need some time to go find that screw that I lost. I feel like an idiot. So I really need to get that off of my mind. So that screw is going to go in bag 9. Hopefully in the next video I will have found that screw and I won't feel like so much of a dumb dumb. Okay. Bye.