Machining a Miniature Lathe - The Apron and Power feed clutch

well if red check marks aren't any indication of how close we're getting to the end of this project i would say that we're pretty close anything that is not checked off is apron related and that is this sub-assembly right here in the front it's got a half a dozen pieces gonna be a little fussy to line up actually because it has to line up the drive shaft at installation so that'll be another video for sure let's start with making all these little components first one in line number 19. and i believe that is the clutch knob be a fun little part right there so so shaft collars are next made out of the same material the clutch knob was just made out of so so these are simple shaft collars there will be two pieces coming out of this little slug right here and in a setup like this you have multiple choices you can make you can zero out on the inside of your stop offset for the first hole calculate the length of your part and just shift accordingly for the second hole because i'm going to cut one piece off of each end or zero the face cut it flip it bank it again it's already on location drill it or you can zero the outside edge and do the exact same thing for sake of visibility i'm going to zero the outside end and flip it when i flip it since the length of the part doesn't change the end on the opposite side ends up in the exact same position so this should be rather easy [Music] hmm so let's take a quick look at the positioning of the apron and why it is so critical all right let's find the casting here's the casting right here these are gates on top and they will ultimately come off you must work from these elevations here because you can't change the location of those elevations so they're very important so they have to be factored into whatever is going to happen next this thing has to attach to the bottom of the carriage move back and forth now on the inside of the apron we have a couple of drive gears we have one sitting there that would be the hand wheel gear and this little guy right here this is the clutch mechanism for when you engage the power fee i think anybody with a south bend will recognize that particular configuration for the for the clutch anyway when it's tight these guys move in unison when you unloosen it this one on the inside is allowed to freewheel from the rotation of the light of the lead screw or the drive shaft and when you torque it down it then moves the carriage and they engage by a cone there's actually a taper on the one and a taper inside the other one so when any pressure is applied they just simply bind up but it's not a very mild taper and that's good if it was a mild taper it might want to press and lock like a morse taper does but this is a 60 degree cone and when they're not under pressure they're very cooperative anyway this guy also sits under there this is just getting too small to touch there you go and i think it's pretty important to see right now we're very clear to see how the center line of those two features those two holes in this apron need to line up perfectly with this apron in order for the gap to be correct from the underside of the carriage to the center line of each shaft and i am going to cheat when i do this 100 cheat and i think it's a great way to do it so anybody wants a copy have at it i'm going to set my bed up in the machine i'm going to use an edge finder against the bottom of the carriage now this still does flop because there's nothing holding it down right now i'll put a pin in the drill chuck and i will space the pin back until i can traverse this bed and get this gear to walk along that rack comfortably at that time i'll know what the number is and i'll know how far up i have to come from the center line of the apron and establish this surface right here for that to work don't ask me to repeat that holy mackerel anyway there are some numbers on the print and i'm sure the numbers on the print are good but they're also very conditional if the height of your bed the features is high low if the notches in your carriage are too deep not deep enough this whole assembly will lift and if you use those numbers you may bind these gears right here and be very disappointed at the very last minute of this build been a lot of work here i will not take any chances i will make sure that the numbers i'm going to use are correct based on what i have here all right let's set this thing up in the mill and i'll show you exactly what that just meant the bed and the carriage upper is very gently squeezed in my vise right here and what i mean gently i mean two-finger pressure on the knob that tightens down the movable jaw now this is on a pivot so i just want to show you how that's squeezed in there single parallel against the machined flat side i'm going to swing this back into position right in line with the bottom of that carriage this is the dimension i'm looking for right there i'm going to show you how to do it [Music] that is a 125 diameter pin in a 125 collet and as the whole assembly shifts to the rear to the camera left right now this gap will get smaller and smaller so i'm going to move it until i like what i see okay minimal backlash now if all goes well when i move the table this gear should walk along that rack perfectly which it does get here check the backlash here if anything is out of square out of parallel this is where you're gonna see it [Music] all right i like it now with my digital readout set on zero i can put an edge finder in here and move over and pick up the bottom of the carriage casting and naturally with the offset uh based on the diameter of the edge finder that you use i will come up with the exact measurement i need for the front of that apron to the gear center lines so that when i screw it together it'll work at least that sounds good on paper right let's put an edge finder in here and come up with a number that's a great way to do that keep that in mind this is one of those fit at assembly moments that you don't know how to do it so i hope this gives you something to think about 125 diameter pin is out the gear is out and the y-axis has not been moved i'm going to come in with my edge finder and register on the bottom of the carriage make sure when you do this that you don't hit any inclusions or casting gates or anything make sure you are banking on the same surface that the apron will bank on so i'm shooting for right in here and yes i did indicate this face to make sure it's running true let's do it whatever reading you get on your digital or your dial make sure you add the appropriate radius of your edge finder to come up with your number 364 and a half on the digital we are looking for center line there it is 365. gotta give him a big round of applause for that that is just right there that also indicates that many of the things that i've been doing on this model have gone right up to this point that is going to be my minimum number i am not going to go below that anything below that you might start introducing a little bit more bind and a little bit less backlash so i'm gonna stay i'm gonna leave this as my absolute minimum possibly stay a couple thousands higher okay every once in a while things do not come to you the way you would want them to come to you and this particular inclusion right here in the casting well you know what's to be expected this is a mass-produced part there was another one on this boss right here so i took the boss lower than the print by about 15 20 000 ish and i will make a brass shim to go in there because that's where the hand wheel goes on this edge right here i'm going to put a large chamfer across the front blend it in and then re-blast it we'll see if we can make that inclusion go away i just can't bring myself to use another piece i did request one the company will probably be generous enough to provide you with one if there's something that you're not happy with but i'm going to put a chamfer on that because it looks like a 45 might clean it up let's find out i like it a little bit of blending and rounding another blast job you'll never see that i'm also going to take a dust cut thinking about taking the dust cut across this bottom just for tooling purposes well maybe not all right let's shift it go vertical i'm not going to cut the bottom i'm going to leave the bottom stock as is i will clean this up and blast it let's do it part is successfully relocated never took it off the fixture plate just hold the fixture plate vertically now gives me access for the 272 actually for the two 172 mounting holes in the top and there is a slot that goes in behind this for the clutch gear assembly that assembles through this hole right here that may be kind of hard to film but i'll film the threading and i'll show you the slot when it's done this is the pocket for the clutch gear whatever with your clutch gear is make sure it fits down in here this is called out as a 125 and the clutch gear is 0.93 so there should be plenty of room and i am fairly sure that that's so that you can unlock the clutch mechanism when the time comes i'm gonna put a slot right down there it goes through one wall so all right the apron is about 99 of the way complete the three gear shaft holes are in there this is a press fit hole there'll be a shaft press fit in there for another gear this is the hand wheel i believe and this is the clutch there's the little slot that i put in mounting holes i think the repairs came out fairly well the champer did take care of the ugly on the front of it i will blast this so it looks exactly the same as the rest of it and i'll make a shim for this so that is not a big deal this will look great i promise you let's take a look at the clutch mechanism clutch mechanism is a conical feature on one and a conical feature on the other and if i don't get that net it's going to make you crazy anyway when they come together under pressure the cones bind and that's your clutch that clutch mechanism fits right in this slot right here put that together prove it and that is the clutch when the knobs turn count or clockwise tighten it up both gears spin at the same time when you turn this counterclockwise yeah you thought it was going to stay on loosen didn't you but i didn't all right the gears can now spin this can stay put while this one spins that's the clutch tighten it up now it turns let's put it on the carriage check the spacing and to answer the questions that are going to come no i had no idea this thing was so detailed when i started it well like anything else if you're going to start it finish it [Music] watch the nap how cool is that clutch gear is 0.93 wide and that slot is 125 so you do have about 0.8 millimeters play in that you will never encounter the face of the casting which is good you see the gap right in there but there is a little way to land and whatever clearance you put between the clutch gear and the rack is going to be the lift that you're going to have on the carriage so watch it move ever so slightly now that is going to be taken up by the drive rod that goes through here and anchors to these two points here so the drive rod is going to hold the apron the apron is going to hold the carriage and all will end well getting close starting to look like something i am only a couple of pieces away from being done with this i have to do the worm the key for the worm and the two anchor blocks on the ends and one drilled and tapped hole here for the gear cluster that mounts to the end then it's time to put it together i do thank you for hanging in this has been a very lengthy series but i am just thrilled the way this is coming out thanks for watching i hope you're happy and well wherever you are in the world joel pi advanced innovations in austin texas i'm out you

Channel: Joe Pieczynski

Views: 24,747

Rating: 4.986228 out of 5

Keywords: Joe Pie, JoePieczynski, Advanced Innovations, advanced innovations llc, how to, machine shop, shop tricks, shop hacks, shop techniques, shop tutorials, EL 1, PM research, miniature lathe, scale models

Id: MNP3L-tfK74

Length: 30min 6sec (1806 seconds)

Published: Sat Jul 17 2021