Machining Tapered Threads for a Steam Locomotive Try-Cock Repair

[Music] hello Keith Rucker grievance machinery org guys got a little project I'm gonna work on today this one's gonna be a little interesting I think a little turning job here on the lathe for the most part anyway but what I've got is a while back I actually did made some new stems for a pair of tri they go on a steam locomotive and when I sent those back to the person that I was doing that job for he went to put them back together and he tightened this part up down here on the bottom this is the bottom half of one of the tri when he tightened it up it snapped off a piece of threaded piece in here that it was just a little bit it's just old and then profiled and been gone through a lot of torque over the years and it just snapped off so what he has done has asked me if I could remake the bottom part of this truck valve and that's what we're going to be attempting to do today this can be a little bit complicated and the fact that we got two threads on here one of them is up against a very tight shoulder which is going to be interesting to do on the lathe but even more challenging and something that I've quite honestly never done before is we're gonna be turning tapered threads so the threads on here our Boulder tap threads there I think it's 12 threads per inch but it's on a three-quarter inch per foot taper same taper that you have on pipe threads but on boiler threads they basically are just a really long stretch of possible sizes that these things can fit up into anyway we're gonna be doing that over on the lathe and that's gonna be the game plan let me zoom you in here show you what we got I got a piece of brass stock here we're gonna make a new piece out of and we'll go over the lathe and get started so here's what we're dealing with and again this is kind of all the components here the top part of this is fine this is the new valve stem that I made previously in a video a while back the top part here while being called up with a pipe wrench over the years there's really nothing wrong with that basically this bottom piece here is what this threads down on to a thread sent on that thread there I think it was inch in the eighth seven I'll double-check that again later when we get ready to turn it but this part down here snapped off and actually if you look you can tell where even this tapered threads on here it looks like it had been bent or cocked a little bit at one time so we're gonna remake this bottom section gonna have the threads on this side tapered threads this side up here we'll turn that down it's got to be cut down the inside and have a matching seat for that valve to go close up in there and then we'll have to cross drill and this is just a pipe thread in here this is just for a little nozzle that comes out of there that the steam comes out this is used to manually check the water level in a bowl or on a on a steam boiler there's usually three of these sometimes two sometimes four but there's several on the boiler and what you can do is you can crack these valves and depending on whether steam or water comes out of this hole right here you can manually determine the water level of the boiler there's a sight glass on there to visually be able to do that but if something were to happen to that sight glass this is kind of the backup system to manually be able to check water height in the border which is extremely important when you're operating a boulder if you let the water level get too low it can lead to a bowl or explosion which is never a good day enough on that we're gonna do this go over here and get set up on the lathe and get ready to start making this fart I think what I'm going to do is we're going to turn the taper in first honestly guys that's where the most can go wrong in this project so I want to get that knocked out first once we get that done I think the rest I would be fairly straightforward so let's go over to the metal lathe and we'll talk about how we're gonna set up do this so I got this founded up over in the lathe and we'll go ahead and start kind of prepping this bottom end and we're going to turn of course the taper in first I'm going to face the bottom I think I'm going to conclude this up in here and then we will start getting our taper set so that we can actually turn that taper so that's fire up the lathe start by facing the bottom a little mark on here about how far down I want to clean that up too and I'm not I'm just going to shave a little bit off of this right now I'm just trying to get a surface that is running true to the spindle I think I've got my taper attachment set up back here and in case you guys are not for me with how a taper attachment works if you look we got this bar back here in the back and it is set at an angle there's a track in here and basically connects to my cross slide I'm able to disconnect the the screw not really it still can screw back and forth but basically as it moves across this back here it's going to move the compound along with that so if you watch as it's coming in I don't know if you can see it or not but as it's coming toward me it is moving the cross slide back at the same rate that that taper is actually riding on that taper back there notice the tapers standing still and that allows us to cut a taper we should be ready to start going here I'm gonna come on in as it gets out there toward the vacuum you're going to see the light get cut it getting lighter and lighter and lighter eventually it's going to run out [Music] no feed-in come back into the car and we are cutting that taper got a little bit of a taper turned on here and I want to actually confirm that we're turning the taper we want to turn so as you guys i've already showed you of using this little gauge that i made to kind of set the machine with and the way I did that was I just literally laid it back here against this template that we're basically cutting against and just lined it up against the casting down there and that was to get me a rough setting and after now that I have got a little bit turned on here I want to come in here and see where I'm at and see how close we really are and see where we need to go from there now to check and measure this this taper what I'm going to use is a taper micrometer now this tool is set up where you basically have two points on this side two points on this side this is a sign bar for all intent purposes you can use that to measure angles with by using some trigonometry we're basically figuring out with this so you know when when these measurements this measurement here reads zero is straight it's perfectly flat we're measuring the difference distance from flat up here you think of that as a right triangle and you can do use a sine function which is why they call it a sine bar to determine the angle or in this case the taper now because of what we're doing is a taper where it's inches per foot this gets really easy because this is exactly one inch between these two pins so I know that if I'm at 3/4 of an inch per foot is my taper I can divide that by 12 and it comes out to 0.0625 inches four inches your taper so we should be able to come in here with this tool we kind of come in here and you get the bottom in where it's touching you're getting the basically want both of these to touch and you want both of these to touch we come in here we get a measurement and I read that measurement and it should be what we've got over there and I'm gonna double-check this yes it's measuring what I got while ago all right I've come in here with my tapir micrometer I've measured that measurement and the measurement I'm getting is point 1 to 0 so the difference in the height from zero is a hundred and twenty thousands of an inch and we're shooting for a tapir of a 3/4 of an inch per foot that comes out to point zero six to five thousands per inch now because this is an included tapir in other words when I'm measuring this I'm measuring the tapir on both sides when we save the 3/4 inch forefoot that's off of the center of this so we have to double that that's 125,000 since what it should be reading if it's correct so basically my tapir is off on the included tapers off five thousandths of an inch per inch or on one side two-and-a-half thousands per inch okay so what I want to do now is figure out how far do I need to move this back here to make up that difference so I've gone back and bit from the center to this mark right here of this bar the pivot point to that bar is 12 inches so again I need to take that two-and-a-half thousands and because we're going out 12 inches that's tapir per foot on one side because we're this taper here is half of the included angle I need to move this times 12 that which is gonna be 30 thousandths of an inch I hope that makes sense basically just you can see it here's some math there's what I did I was shooting for 125 I got 120 that leaves me five thousands that's the included angle so I divide that by two that gives me two and a half thousand multiplied that times 12 because I'm coming out 12 inches on that sign bar or that taper bar back there I need to move it 30 thousandths of an inch and we should have it exactly right and it does need to get larger so it needs to move away from me let me go get some wrenches and we'll go back there and see if we can dial that bar in the needle comes toward me it's moving this way I want to go away from me so the dial needs to move in this direction I'm going to loosen these up loosen this one up and now just loosening it moved it a couple of South I can adjust it right there there's 30,000 switch is what I want to go to and all right that didn't move I figured whenever I tightened it up that wouldn't move all right that should have my taper final adjustment made in there I'll clean that off makeup cut pass or two will recheck it with the taper micrometer and make sure we're right on the money we should be all right we're just making our pass down through here [Music] so that should be cleaned up now with the new taper I'll get my taper micrometer back out I'm going to be honest with you when I made the first adjustment while ago I went in the wrong direction so I had to move it back 60 thousandths I actually take up what we did wrong plus compensate for what we should have dialed in to begin with and if this measure is the same I should be right on the money let's get a good measurement here this thing can be a little bit aggravating all right and we're shooting for 125 which should be zero on the dial there and all right so we are according to that 310 thousandths of an inch over I can live with that we have our taper set though now we have our taper set it's just a matter of turning that taper in there and getting it down to the dimensions we want so we'll turn our way basically we're going to do this just like we were turning it straight I just take a little bit at a time until we get down there I'm probably going to just turn it up to about where we've got it going right here right now and then I'm gonna I'll have to kind of transition this area in between after we get the taper in there but that's kind of the end of my taper and anyway we'll freehand that in or something put a different angle on that to transition between there let's fire her up and get to going start taking some little bit heavier cuts here now that I got my angle set where I walk we'll get those cut on through this instead of that shoulder right there [Applause] [Music] another pass [Music] I went ahead and finished turning this out I put a little chamfer in there it's just a 45-degree angle going down through the taper I've got this set up now to do 12 threads per inch and I want to just do a little scratch pass on here to make sure I've got everything set up exactly where I want them to be on 12 and let me just make sure double check all my settings here I think we're about ready so let's engage this so let's engage this we're going to go out to that line right there and just back out I want to check that with my thread pitch gauge we're on 12 + good start cutting some breads and see is following the taper just like we were cutting with it while ago and cutting threads here is going to be exactly the same as it would for anything else but instead of going flat across it we're cutting it at a taper [Music] [Music] I'm basically just doing these until I get a sharp point up on the top because of the way this taper works there's really not a test fit here I'm just doing a scratch pass here I actually like that that looks good right there I think for uh we're gonna call that good all right I think we're ready to go ahead and park this to law for this part off and we'll turn it around and finish on the other side so I've got to mark there where I want to cut it let's get this lathe fired up it's just part until down through there come apart turn around backwards in here now we're gonna work on this side and basically you need to turn it down this is an inch 1/8 diameter I got a mark on there about how deep we need to go and get that and then we'll have to thread it so come in here that's all [Music] [Applause] barely fuzz that we were he'd take off about and that's reading right on the money all right good job me face the bottom of that I want to face okay this next step here is cutting these threads these are seven threads per inch pretty coarse pretty deep threads and to make even more fun we're going to go up against the blind shoulder here which is gonna make sure that I have to stop it and pull out of there as quick as I can when I get down there at the end so I've got to lay the slowed down pretty slow as you can see when we engage the half knot it's making a pretty good run down through there of course I got it taken out a taper mode and all that kind of stuff right now so I'll tell you what let's go in here touch off I'm gonna do a scratch pass here make sure we're where we need to be and that looks like seven threads alright I won't make you guys watch all of this make our way down through there I'll bring you back we get a little closer to the bottom we're getting pretty close down here to the bottom that is a little bit snug but it's really really close as well so let me just take another bow or two out of there and we'll Whittle it down in there that's tight let's think about another towel out of there we don't need much more it was hidden in that root down there didn't hit the face but I think this is probably going to be right where I need to be yeah that I think it's going to be good very nice a little gap in there but that's what we had before that's bottoming out I like the way that feels so I think we're good and that thread is just about perfect all right so next need to work on that inside part there get that drilled out and get a seat down in the bottom this into the right right angle let me figure out what we need for that got a countersink on here this is a 90-degree included angle it matches the seat that will go down in there so I'm basically just going to cut that seatbelt on the bottom there it is and we'll cut that in there and I believe that seed is going to work just fine this of course will screw that in their seat right down the bottom in that top piece that's what to open and close the valve so I think we're good to go there now my quarter-inch hold is not all the way through I'm going to leave this checked up in the lathe until I can get a longer drill bit and get that done but before I do anything else I think what I want to do is go ahead I'm going to screw this piece back on and I want to just clean that up get all that roughness off of it it just looks bad and we can do better than that so we'll get us a tool here and just come in there and clean that out alright that looks a lot better and I'm gonna well I'm there I'm just gonna came from the back of that with that cutter that's in there break that sharp corner you can definitely tell this to different materials but I think it'll be fine I'm mixing up some lapping paste here this is time-saver this is their course and basically it's a powder you mix it with a little bit of all make a paste the nice thing about this time saver stuff is is that it was made by the are invented by the Navy is what I was told back in the fair in World War 2 where they could use it for lapping in propellers and stuff on ships and if you didn't get it all cleaned out it breaks down over time so it's not a big deal which is nice and a lot of applications where you don't have to worry about getting it cleaned up this one here we could clean it up wouldn't be a big deal but hey it's nice to use this stuff and what I want to do is I just want to lap those two surfaces together so we'll fire the laid back up I'll just feed them together down in that bottom we'll hit it a couple of times I'm not sure how deep this is all right I'm just gonna do that a couple of times putting some fresh compound on there every time until I get a nice nice finish in there too good mating surfaces alright I feel pretty good about having a good seat down there now and go ahead and take this out and I'm to the point now where I just need to get my longer drill bit before I want to take that out of the lathe so I'm gonna go ahead and get that order tonight and we'll finish this video up once that comes in got my long drill bit in now order that for mcmaster-carr came in we're gonna go ahead and finish grilling this thing out and I think we're through next thing we got is a little pieces drilled and tapped kind of crossways to this it's just for a little nipple to come out that the seam actually comes out of and that's tapped quarter inch or excuse me eighth inch national pipe thread eighth inch twenty seven so that needs to be drill with a letter S drill bit according to my drill chart that's what I got in here spot that get us place started and the Frog thrilled all right there we go we got a hole drilled through it got my tap in here with a tap foul or going right down that same hole that we drilled there and with the pipes habits of tapered tap and I actually put a mark on there I actually screwed it down into the old original part to see how far it would go down or at least that black line but that's how far I want to tap down to it's pretty much matches the depth of tap in the old one we had [Music] that's it right there and with that I think we have this job finished ivory assembled the Tri of course here's the broken original piece new piece we made for it and refreshed up the old existing parts here and put it all back together this should service him well I do believe you know one thing I've thought about doing was milling some slots in here to put some wrenches on this but he told me he wanted to leave it like it was but just to keep it original why they made it where you had to use a pipe wrench I'll never know but that's the way they did it and he wants to leave it like it is so that's what we're gonna do but anyway there you go turning tapered threads machining brass learning a couple of threads on the lathe a nice little project here nice little fun little project and I think this is gonna work out just fine for him only thing I wish that we could have done a little bit different was match the brass here in the long run I don't think it really matter this brass down here is what's rated for doing with steam fittings and so forth which is why I purchased this particular grade I remember which one it is but obviously it's a little bit different alloy between the two but hey no big deal it's gonna it's gonna work just fine and just like that another job knocked out here we'll get this back over to our gentlemen that we did this project for and he can hopefully get it back on the locomotive and have it going and another project finished here in the shop as always guys thanks for watching please subscribe if you haven't already thumbs up or appreciated on these videos and with that we'll catch you on the next video [Music] you

Channel: Keith Rucker - VintageMachinery.org

Views: 103,503

Rating: 4.9705548 out of 5

Keywords: Machine Shop, Machinist, Lathe, Milling Machine, Restoration, Vintage Machinery, Metalworking, How to run a lathe, how to run a mill, Keith Rucker, VintageMachinery.org, vintage machinery keith rucker, steam locomotive, try cock, tapered threads, thread cutting

Id: FaHYXAjqDpw

Length: 33min 25sec (2005 seconds)

Published: Fri Feb 21 2020