Machining a Model Steam Engine - Part 19 - The Crankshaft

well it is with mixed emotions that i approach the last piece in this build i have really enjoyed this and i appreciate all the support and comments that i've been getting thank you all very much here it is the crankshaft i am uh going to start the same way i start with all the other castings i'm going to take off all the ugly on this and i'm going to check and see how straight it is this way and this way so see if i can get away with a little bit different approach on this ultimately yes it will be finished between centers but why rough it between centers when all that noise takes place if this thing is straight and you can trust these diameters well grip it here turn this grip it here turn that and don't turn them to the finish diameter of course if this thing is bent or running out you want to make sure that you leave sufficient material to clean it up between centers at the end but i'm going to rough it out completely different than roughing it out between centers and if i like the way it looks when i put it up between centers and it's all running true i may just finish these guys up held in a collet or such and then finish these up between centers because that's the only critical part about it they do give you well this is critical diameter as well they do give you a reference drawing in the pm research kit for a fixture that you can make and no it doesn't suggest using hose clamps but i guess if that's uh what makes it work that's all that matters so who knows i might end up using them too so i better not say anything too quick there the one thing i did see and everybody that's now rolling their eyes about that last hose clamp comment was the other builder that did this mistakenly turned this diameter all the way to this face and then used bronze shims on either side of that particular feature you know what i sent her a message offline and said nice job and i really did like the creative recovery of that particular bronze shim i think it's actually better than the cast iron elevations or the bosses that they have here and if i can find a piece of bronze laying around i may just copy that because i really enjoyed that i think it was a great way to think on your feet and recover on the fly all right let's take this over to the sander let's take it over and hit it with a file wave the magic wand make all this ugly go away and take another look hang around ah [Music] to get a feel for how straight this casting is i'm got it sitting on a small surface plate on my bench one two three blocks on it and i'm looking at the gap between the casting and the top of the block and that appears to be relatively straight the only way to be sure is to go 90 degrees now look at it again it does crown a little bit but beware that little gap right there if you think that's only a small gap if you were to hold that in a three-jaw chuck or some other method supporting it by this end that becomes a projected error and when it lays flat on the blocks the distance that this dips or rises depending on that small gap is like a gun sight when you're looking 100 yards down the range you may not move very much at the table but you're three feet off center when the bullet strikes the paper so beware small gaps like that when you correct it all on one side of a fixture or one side of a part you can really end up in a world of hurt on the other side i might put this in a three-jaw chuck and just dust it anyway so i can trust the surfaces just to clean them up this is a 511 diameter cleans up at 374. so quickly in my head that's about 12 7 millimeters currently and cleans up at around 10. so i can take a dust cut on this and get a better feel for what i'm working with still going to do it between centers though ultimately why not all right off to the lathe first step in my process is going to be to put a drill blank a half inch drill blank in my three jaw chuck and i'm going to get that to run true and use that as the standard setting i'm not going to adjust anything i am going to turn the journals one at a time and regardless of what happens to the center of the part the end that's trapped between centers will remain linear and can be center drilled in a step like this should you choose to approach this part this way rotate the crank in the chuck and turn the machine on until you get this end of the part to run as true as you possibly can or true to your liking i know that i have a considerable amount of material coming off of here so a little run out is acceptable but i've got it pretty close you can see the end i sanded the end off because it's going to be very hard to machine this off and the sanded surface is going to be fine there's nothing that's going to reference that just make sure that your center drill is not influenced by any tilt you may have in that surface i may try to face it off as set right now but because of the extension i just have to imagine it's not going to end well it may chatter a little bit so i'm going to try to center drill that first let's take a look at how clean this thing runs it runs rather well i'm surprised does call for a number two center drill [Applause] just for aesthetics i think i'll go with the number two nice and easy so you have a good footprint on the end the drill's going to want to wiggle around this is an extended center drill a shorter one would probably have less of a tendency to want to jump [Applause] there we go [Applause] [Applause] on an extremely critical part if you're putting a center in and you know that that center has to be true set your compound to 30 degrees 60 degrees whatever angle it is that you need and if you can get in there and single point that you'll guarantee that the concentricity is not affected by the setup just change over to a live center and dust that od the small shoulder diameter adjacent to the journal area is called out as half inch or 512.7 millimeters if you are going to rough turn this down prior to going between centers try not to go below that diameter if you intend to keep that feature on that part in this area right here this is a bigger diameter than this i'm only roughing this now be careful about that diameter right there let's do it [Music] i'm pleased with that it's relatively clean relatively concentric up here to the casting that's a good thing i want to take this to a diameter that fits in a collet so i'll stay with a regular recognizable sign cut it to whatever size you can hold comfortably for the next stop currently positioned in a 3160 forts 5c collet we're going to test the validity of the last setup these should be running very concentric if you just took your time and made sure that both sides of this are the same diameter just for this reason let's turn it on look at that end right there [Applause] [Applause] so i'm gonna stick the center back in here get a little bit closer to the 374 and take it down around to the 400 mark leave myself about a half a millimeter to clean that up between centers because i know these things like to jump and chirp and bang and make all kinds of obnoxious sounds when you're trying to do it the way it should be done so i'm going to cheat and get close before i ever have to worry about that let's do it uh [Music] and for sake of not bouncing your setup completely out of the between centers dog driven arrangement that you're ultimately going to have to deal with this would probably not be a bad time to establish the 500 diameters on the print and the width of this right here because you know you got a good solid setup you start doing an interruption in between centers and this thing is going to sing and chatter and just really let you know it's not happy so consider it it's definitely an option 423 i'm gonna go for 406 406 23 right now we can consider the part roughed at this point because this is what it looks like starting to look more like the print that's a good thing this is where you get your calipers out get your scales out get your microscopes out and start comparing what you have here to what is shown here this is where you start needing to pay attention of what's coming off of what surface so i'm going to do a mechanical inspection on this i'm going to compare what we have or what i have and i will know exactly what i can get away with back in the setup i am going to do the interruptions with the exception of the eccentric i am going to do the interrupted surfaces in a collet pinched right here on one side naturally in the center on the other side but that will greatly reduce the banging going on when it comes time for this to encounter this eccentric swing right here because boy i tell you between centers you can expect that to just make all kinds of noise i might have said that five times already but that's why i'm going to double check it see what i got we'll put it back in the machine and clean the surfaces up after a little bit of inspection you're going to find out that that protrusion right there those two arms that support the journal are almost net shape there's about five thousands that can be cleaned up off of each outer face now that is not the critical dimension the critical dimension is the width of the entire unit to those 500 shoulders on each side that's what's going to keep this thing centered in the frame and drive the casting accordingly you also want that center journal centered about that one inch 250 thickness of the part here and you have all the collets i have the one size that i size down to that particular collet is missing from the set and i have no idea where it is so yep i've got to shim around the shank got to do what you got to do right all right i'm going to clean up the outside edges of both sides of this thing and i'm going to turn the 500 diameter on i'm going to do it to print for now but i really like that bronze pushing idea and i may put shims in there after the fact let's do it once you've successfully cleaned up both sides of this protrusion i'm sure there's a technical name for it but it i don't have it right now so forgive me if anybody knows what they're called that hold that offset journal by all means let me know what it's called there is a 45 degree call out on each of the outer edges here and over here and just for sake of getting cleaned up i ran a tool across the od as well let's do the chamfer [Music] [Music] plan is a single point that 45 on there i'm just getting too much chatter with the extension of the tools uh the part is pulled out of the collet about another hundred thousands to allow for the half inch shank tool that i'm using to clear the back [Music] side very consistent no bounce in the tool nice turn finish let's flip the part around do that again [Music] [Music] i'm going to remove the part check those chamfers with a depth mic if it needs to be re-cut i'll mark it and re-cut it stay tuned back in the lathe for the final turning operations on the outside diameters of this part after a couple of calculations we are looking at approximately 130 out from each of the faces that's already been established now i'm almost ashamed to admit that i did not have a dog small enough to drive this diameter so bring one up split cap on this side because that diameter is going to change operation to operation first time it's going to be bigger second time's going to be smaller and this is fixed so the center to center is fixed and this diameter this cap is got two screws so that comes down it cinches down this is just strictly going to be a back and forth and we'll see if i can get some of it on video for you but that's the center to center and you just can't beat turning something straight if it's done between centers hopefully this has no influence on on the part because usually these float but i trust the setup and i'll see whether or not it works out that way i've also got the mass of the crank opposite the mass of the clamp to try to balance the setup [Music] out this is the configuration that i will be using for the final turning ops i've taken it out of the hole and just allowed to drive spring-loaded so it doesn't vibrate i am going to go with the conventional bosses on the print to start and i may turn them back maybe not all the way to the outside of the casting itself and maybe halfway and just put a small washer on it because i like that idea anytime you can keep metal on metal from happening the better off you are so there's no sense in showing the actual complete turning of this i am about 10 000 away per side i'll get it very close and then i will polish it up and we'll cut this center out here i'm using a different camera for this and i'm actually kind of there you go there it is we'll solve this out and hope that there's no stress in this material because if you saw a web out after doing such meticulous work to get everything straight and true and clean and any stress in the work could cause it to pop that would be most unfortunate so we will pick this back up as soon as i get these sides turned to 374. 374 on the print that's what we'll shoot for [Music] side number one is complete and i figured i would show you the technique used to get such a beautiful finish on cast iron because turning a finish like that on cast iron can be challenging if not impossible so i'm actually going to do it the old-fashioned way and a lot of you all-timers out there are going to go you go boy i'm going gonna do it with a file believe it or not i will get that finish on there with a file but you gotta trust your file that's the whole secret here i'm going to use yeah this is about a three-quarter inch wide extremely fine and this is my it might as well be a diamond lap because i just absolutely love this i try not to do corners with this it's only ever used for flat surface cutting and the way you can tell you're cutting flat or not i'm going to put a dark line across here and when you bring the file down on top of it you'll be able to see exactly what type of path your file is cutting is it cutting on either side or high in the center or what it's doing and if it takes a nice bite off the line initially you know you've got a file you can trust and you need to put that one on the side and just trust it forever so i'm going to reposition a camera maybe not this one and i'm going to show you what we can do with a file okay you start off with a line you can trust i think you can see it right there make sure the fire is clean here we go [Music] nice light splash you can see that the track that the file is leaving is relatively reliable that was a very superficial pressure and you can't tell when you initially do this whether or not it's the contour surface finish of the part or the file that you're going to use so trust it for a couple minutes and see how it works for you [Music] so and that is a very consistent very consistent removal of that blue line that is just beautiful surface finish is getting much better much quicker and dimensionally we can give it a little bit more pressure if you have one area of your part or another that you would like to address with the line back on that and work only in that area removing that line on this particular part is going to take off about three tenths [Music] still see some shadow of the line which means the ink is down in the grooves of the part so the surface finish could be better i'm going to take it right to the number i'm shooting for and i will finish with emery sitting on 374 right now and i can expect that to go about a half a thousand by the time i'm done this is very smooth [Music] [Music] so [Music] [Music] [Music] that finish is looking pretty good if you are going to check dimensionally after the fact make sure the part is cool if you're not sure if it's red hot get somebody else to test it i'm only kidding you can usually tell all right go for some scotch brite [Music] okay right now i'm going to do everything in my power to bring the center to or the edge to edge dimension in so that it fits within the frame i believe the frame is called for one h253 looking for a one inch 250 across these i should have a couple coming off each side two and a half with a very sharp nose tool i'm going to clean up the inside of that and i'm going to run it down and create a small relief right there both sides so that's pretty if you're doing this and you're wondering how far to come forward with this inside relief this gives you a pretty good idea i would say realistically you don't have to come forward very far there is plenty of room in there next phase of this operation is to create the eccentric lobe to drive the connecting rod i am not going to beat this to death in an offset setup i'm going to put this in the mill i'm going to clamp it in the vise and i'm going to clean this center section up leaving minimal amount of material so that the interruption is minimized and the vibration will be minimized so that'll be the first step then we're going to put it in the suggested fixture and make it a little creative there stick around all right now for everybody that's already typing the comment we're going to get back over to the bench and we're going to cut this piece out we're going to relieve it out first with a hacksaw i'm not even going to put it across the bandsaw then i'm going to rough this slot on the mill because interrupted cut this side is going to want to sing and this side is rock solid so that would be the next step i like it getting close i should rent these fixtures out i'm just saying i should put them all in a box little behind-the-scenes warning here make sure that when you remove one of the webs in the crank that you remove the one that's in line with the journals that you've already turned don't make the mistake and remove the other one remove the one that is in line however you have to you'll see the benefit of having a turn surface here it'll give me something to sit on that's parallel and give us a nice consistent web once we dial in center part is simply sitting on parallels in the vise with the saw cut side up this is where you can customize this crank to your needs if for any reason when you did your connecting rod if it ended up too thin well then just accommodate this make this thinner accordingly the print gives you a five thousandths difference between the center of this this opening right here or the size of this opening and the size of the connecting rod so about two and a half thousands per i'm side take an end mill come right down through the center of it leslie and that will give me a much easier target when i get into the lathe go on the fixture i'll be able to center up my tools a lot easier because one side will be inaccessible at that point front you can probably still get to the back side you can't unless you take it out and then you risk losing your concentricity okay let's mill this out once you have clean surfaces on the inside that you can trust here comes the math figure out what size the slot currently is measure both of these uprights you want these to be the exact same thickness so adjust the center of your cut accordingly to move left or right to balance these out and then you'll know how much more to move the cutter to open up the center slot but now is a good time to take a couple of measurements figure out where the actual center is if you didn't pick it up with an edge finder i did this by eye i know the cutter is undersized so give me a couple of minutes i'm going to measure this up find my center and i'll be back i'm going to have to beg your forgiveness here for a second sometimes i just skip over things that i take for granted and second nature i want to explain how to pick up that center i think it's important if you've never done it it could be a head scratcher so let's just take a quick look at what's going on here these are theoretical numbers these do not represent what i just found on my part but for sake of demonstration i think it's important to show you if you measured this thickness right here and it came out to be 280 and you measured this thickness right here and it came out to be 300 well the difference in those two numbers is o20 which one is smaller this one is smaller so we need material on this side so that it gets closer to being this size we'll take this number take the difference between that these two numbers which is o20 total and split that in half that is how much this center line needs to move in that direction ten thousands once you make your shift dust each side again and watch for these numbers to deteriorate and increase or deteriorate and increase and get closer together that's the way you're going to track your center after you've done that and established on your digital readout or on your dial when you have a dimension that's exactly the same on each side that's when you go for the gap in the middle and as the gap in the middle increases these will decrease symmetrically and everything will be about center okay i hope that's clear and sorry i skipped over that that's kind of important let's get back to the [Music] part i'm gonna go to my bag of tricks here and stick an expanding parallel in my part squeeze it now i have a positive surface i can run the mic on get a pretty good feel for where i'm at and i'm looking at 4 32 well i'm right there i'm right there another light dust cut on either side we'll go back to the lathe and finish that journal watch the gap on that side you can see that the screw does give it some adjustment center to center this way is fixed this is not going anywhere 750 because it was hard set and reindicated after the fact if this journal looks off center this way to the body these are the screws that you use to put it back on center right there remember it will be pinched in the chuck under a jaw so in order to make any type of adjustment you may have to unloosen the chuck to do so there it is how to work it in there all right let's go set it up here's a final look at the tool there's a very good angle you can see that the undercut i put in the center initially to reduce the thickness of the lance i then went back in and created an angle on either one of those lands leaving behind a very small straight section that you can barely see but it's there then after that i went in and i necked the tool back so that it wouldn't catch on the inside of the journals got a secondary tool relief on either side of this tool so i don't have to worry about the lugs hitting the parting tool it is cut back only the very front is cutting and i'm going to bring this slot to width the diameter is complete but the width is a little bit snug for my liking it will probably work but it's just a little tight and can't take the chance let's clean it up so so that's a beautiful thing right there i don't like it all ready shine it up watch your fingers on this step that's for sure all i'm going to do is put some strip memory in there and take the ugly off and we'll take it out take a look there's the final product little blend on the inside still got the 500 diameters on the outside i did not put any bushings on it i may go back and do that i don't know we'll see but this is what i want to see right here like a kid on christmas right coincidentally it is christmas let's put the rods on like butter love it cross head drop everything in place well you can't even feel it look i absolutely love it well that'll mess with the autofocus won't it here i am no i'm over here oh just beautiful i couldn't be happier i'm going to clean it up i'm going to go back over the print see if there's anything on the print that needs to be addressed as far as tolerances are concerned some of these holes are called out as the same size as the rod and being an ocd virgo new jersey tool maker i chose to hit the number right on the number if it said 188 the hole was 188. so if there's a rod going through there that's 188 i will probably ream it out to 189 190 depending i could just sit watch out all day that's just too cool all right guys it's another installment and i will be back to put this thing together for you and take a lot of really super close-ups because i am thrilled the way that looks fantastic thanks for coming along do appreciate it joe pi advanced innovations in austin texas i'm out if that doesn't make you smile you're in the wrong trade i love it you

Channel: Joe Pieczynski

Views: 136,581

Rating: 4.8825102 out of 5

Keywords: Joe Pie, JoePieczynski, Advanced Innovations, advanced innovations llc, how to, machine shop, shop tricks, shop hacks, shop techniques, shop tutorials, steam engine, crankshaft, model building, PM Research, eccentric turning

Id: xoEiuDLje5k

Length: 45min 37sec (2737 seconds)

Published: Sun Dec 20 2020