Machining a Miniature Lathe - The Cone Pulley - Dimensional Crash ????

next piece of line on this model is the cone pulley this particular kit came with two cone pulleys which they were so nice to supply we have the one for the main drive and the other one is for whatever mechanism you're going to use to drive it and they should be opposed to change the gear ratios there's about forty thousandths about one millimeter worth of extra material all the way around on this and this is an interesting setup this is part of the back gear mechanism that goes all in here and i'll tell you when this is put together it's pretty cool but i am very disappointed with the fact that this is not a functional bull pin it will disconnect the gear from the step pulley but it's not the kind that you can reach in there and pull out like an old south bend i'm sure a lot of you guys are familiar with that i'm going to make a brass arbor for this first thing i'm going to do is clean it up of course so i can do something with it as far as holding it is concerned there will be some pressure turning there will be some drilling there will be some reaming and after that we're just going to make an arbor screw it down and have at it one of the features on here that's going to be not difficult to do and it's probably not critical because this radius right here a one inch diameter crown radius and that just means i mean it's a crown radius but you can have a one inch diameter on a 500 diameter so all that means is just what it says a crown radius one inch long 250 steps 1 8 inch give or take incremental steps on the way up and it should be relatively easy this 312 diameter here is a press fit for this component right there and this component slides on the spindle and everything just articulates three wheels this not so lucky this has to press fit on here or screw down i would rather see a press fit but that's going to be a little tough to do all right let's clean these things up cut some metal first step is make the pressure turn over this is not a big deal at all if you're going to pressure turn anything make sure it's not going to migrate back into the collet or chuck that you don't want to do that 7 8 diameter brass i'm going to turn it down to 750 then reverse it and put in a three quarter collet and it's not going to go anywhere no matter how much pressure you put on [Music] it my knowing that i'm going to be holding on a larger diameter i have a small recess in the face of this to avoid the chance of the part rocking if the tool is off center it's the only reason i just did that i will face it again for smaller diameters with the parts securely pressed against the brass arbor that i just made i'm going to turn the four diameters that are required i'm going to i know that from contacting the tool to the face i'll tell you what i'll just show you once you have your slug turned and reversed and put in a smaller collet it's not going to migrate into the collet with pressure take a dust cut on the face and zero out your digital your dial indicators or whatever method you use to track the carriage movement [Music] now with the tool zero to the face of the arbor any cut that you make on here you'll know exactly where that cut is located knowing that i want to remove this at a later date i'm going to move all the way out to the end and i'm going to face the end and turn the steps i'll move my hand so you see it i'll move the tool all the way out to the end and take a face cut as close as i can get to the driving center and so long as the tool does not go below the required overall length of the part i'm good well that'll make a whole lot of sense here in a second i'll stick the piece on here go with a very slow rpm and tap it till it runs true [Music] okay the part is adequately running true i know that when this piece is finished it's an inch long knowing that the tool is zeroed on the back surface i need to stay within that one inch range in order not to blow this part i want to leave a lot of material in the back so i'll do all my work in the front watching my digital not to go below the one inch mark as a matter of fact i want to leave it one inch 30 one inch 25 so i can turn it around and face the ugly off the back it's a matter of turning four diameters concentric and four shoulders one two three four and then i'll flip it around face the back off and we'll put the through hole in before it mounts on the arbor for the radius features on these steps the steps at this point are just going to be a visual reference for the form tool at a later op let's do it if you are going to pressure turn something like this and there's a through hole to be placed in it at a later date make sure whatever center is in contact with the part is a smaller diameter than the through hole so whatever nub is left underneath that center will disappear when the hole is pushed through so all right here's a little piece of shop trivia for you if you're ever turning in an extremely soft material gummy sticky material like this cast aluminum is and the finish goes from very nice to crappy to very nice to crappy that is because the material is cold welding to the face of the tool and under pressure the additional cutting forces knock the chip off of the tool and it cuts better that's the shiny part and then it builds up again and that's the torn part and then it cuts better again so it's a lather rinse and repeat scenario when that happens you're going to need to stone the tip of the tool i'll show you what that is it is easy to throw terms around when you are comfortable with the terminology but for those of you that are not ex experienced enough or have ever been exposed to it when i say stone the tool because you have galling or cold fusion right at the very tip of the tool where it cuts right there drag your fingernail across the cutting edge and if it hangs up you got something stuck to it we do have a term for that but in order to maintain the g rated rating of this video we're just going to not tell you what that's called but it's fly it's fly excrement let's put it that way you've got supply excrement on it you need to get that off sometimes simply applying pressure to the leading edge will be sufficient to dislodge it sometimes don't apply a lot of pressure if it's a carbide tool you can chip the tool if that doesn't work take a file to it take the stone to it and by stoning i'm talking about we're just going to lay a nice stone across the front ground edge roll it back and forth feel it again still present let's go for the top be very careful when you stone the top of your tool to remove the you can see it in the reflection that little shiny part right there that is not supposed to be there make sure that your stone is in line with the rake of the tool so you don't wipe out your cutting edge and the front as well all right no more protrusions put it back in the machine [Music] not all you guys that are going to type comments about why don't you just make this from a piece of bar stock do the entire part and part it off that would be the absolute perfect way to do this but i'm going to go with what's in the kit and i'm going to do it like you have to do it if you don't have bar stock if this were a continuous aluminum bar that would be the ideal way to do it the piece could take the pressure from the form tool it could take a boring ream operation and it could take a part off and you'd be done but now i got to flip it around i'm going to face the back off to the overall length now i'm going to put it back in maybe locating on the id under pressure and put the radius on but right now i'm not going to put the radius on the journals here because i just don't trust it from the pressure it's going to be a lot of surface contact and i don't want to see it jump out okay let's take it out flip it around each one of these is a nominal imperial size so it's going to make it real easy to hold say once you know the od is running and the face is running true go ahead put the mounting hole in can't argue with that so in order to guarantee that the reamer is going to track true through this part and not follow the drilled hole predominantly i'm going to put a small lead on the size of the finished hole so high speed steel straight flute chucking reamer six flute 320 rpm wd-40 is coolant do not hesitate at the beginning if it chatters it could be a problem [Music] all right a shorty look at the parts they are not complete yet the diameters are all still straight and not domed as called out on the print one of these belongs in the lathe and the other one is the drive mechanism from whatever outrigger i will rig up and rest assured i will got to put the bull pin hole in the back and then we'll mount it back on the arbor and put the radiuses on and stick while the gears on stay tuned before i move on to the crown radius detail i'm going to put the 330 seconds feature in the end now if you're building this and you have a precision issue or fear of hitting this with the mating gear this can be a slot it can be a small elongated feature because it's strictly a driving feature for the set screw that's in the headstock gear i'm gonna do this in a five seat collet in the mill set up for this operation is very straightforward 5c collet block squared up with a 1 2 3 block indicated in true so the form tool is required to do those one-inch domed radiuses and this is my setup for laying out the tool i have a one two three block in my grinding vise that i'm going to use as a backstop a 7 8 parallel and a quarter inch wide tool now the center of this tool is now one inch from this surface so when i take a two inch blank and lay it on top it registers quite nicely and puts the center of this radius right on the center of that tool it's just a matter of blowing it up describing it and grinding it let's do that it is an exceptionally mild feature exceptionally mild i'm going to do this on the corner of the grinding wheel and probably file it in for what it is i'm not going to lap it in it's just not worth it foreign this is the same piece of brass that i used to pressure turn the cone pulley originally i just put a 312 lead on it so it'll go down inside the bore on the part i've also fabricated a pusher for it big center drill on one side turned into the 500 which is the lead diameter of the pulley and another 312 so it will be trapped effectively quite securely unlike some things in this shop all right let's stick this right on here and these diameters are finished size so i will blue them up or black them up or whatever and i will look for the radius to approach tangent that's when i'll call it a day let's do it there's an awful lot of work it could be avoided by doing this out of one inch material or 7 8 material for that matter so anybody at pm research if you're listening make this about a half an inch longer and give the buyer the option to do that certainly would make it 100 times easier i'm going to bump the tool against each one of the steps to set my depth there may be a crown because the side of the tool is relieved and it's about a thousand and a half under size on the width but a chamfer will take care of that so here we go [Music] all right that is a super mild feature that's almost not even worth doing but it does help keep the belt centered and tracking and in place so i'm going to knock these corners off with a 45 degree tool at this moment shine it up [Music] so you can see the mild crown on each one that will help the belt track this is the helper pulley this is the one that will be outside the machine used to control the spindle speed not the gear ratio but it is a spindle speed thing we do the exact same thing to the other one but the other one has a dog hole in it for the back gear adjustment otherwise it's exactly the same next step in the process is to press the head stock gear into the cone pulley this was not videoed it is just simply a turn diameter drilled piece of gear stock i'm going to use the press-f8 arbor or the pressure turn arbor that i just used to do the cone pulley for the installation to keep everything straight so and out of the vice next piece in line is the gear that goes on the back of the spindle relatively straightforward a very primitive setup for the set screw operation and just one tip here for you i am trying to get the set screw directly in the center of this little boss down here and to indicate that is almost impossible this is also gear stock so although it's round it's going to be incredibly hard to indicate as well in a situation like this you can tram either side of your v block if you know that your material nests in the center and you can check that on a surface plate i know mine is true so i'm using the edge and as far as the back of the vise is concerned that will be my registration point a 100 000 touch finder when i kick out on the back jaw i will have to move about 53 thousands to get into the center of that hole or the center of that boss so i'll let you find the v block i'll edge find the vice jaw and i will just trust that the planets lined up this morning and my hole is going to go in the right spot pretty sure it's going to work out let's do it [Music] and for situations just like this double ended center drill that i have relieved down to clear setups just like that since a 1 8 is not going to go in there this is sub-surface this will [Music] [Music] a really good example of how dimensioning and tolerancing can come up and bite you in your butt just on display right here the distance between these two gears is called out on the print as one inch the length of this cone pulley is called out as one inch using the standard plus or minus five that they've given you this could be 995 this could be one inch double o five at which time you engage the back gear and the insides of the gears will encounter the insides or the outsides of the cone pulley this is a definite problem right here in the very corner right there if we were to move that gear out chances are it could encounter that casting at full mesh you can see just yes it will [Music] so the best option here is a thinner gear i have two options i can make another one of these guys or i can chuck this up and dust clearance material off the insides of each one of these gears and as much as that kills me that's about the only option at this time if i don't feel like making new gears so we're going to put this back in the machine i'm going to chuck up on this 3 16ths diameter on the end here put a center in it and dust ten thousands off each side and we will revisit this and you can see the clearance that will be present at that time so [Music] all right 10 thou cut off the inside of the larger back gear gear and that's where you get to find out whether or not your press fit is any good a razor sharp tool i just recently sharpened this tool is a big plus when you're going across a brass interruption like the gear presents you don't have to spend the whole day trying to debur it i completely expect the insides of these holes to be adversely affected by the pressure of this center which i'm not very happy about but it's going to happen for something like this the tail stock is unloosened at this point and i'm just turning it to the point where the tail stock starts to move back that's the only amount of pressure i'm putting on that piece just so that it doesn't mushroom the hole and 10 off of this side as well i will make notes on the prints on this for anybody that's curious let's take a final look at the progress up until now the only thing missing off of this assembly right now is the main spindle gear and the spindle itself the piece of brass that's placed in there is just strictly for fit and function and just check everything out see how it's all working out this would be back gear engaged because you can see the gears in the back are meshing which in turn drives the smaller gear the smaller gear will drive the larger gear the larger gear will drive the spindle so when you engage the back gear the cone pulley and the spindle gear are floating they're independent of each other and see how the gear ratio would change considerably slower the eccentric collars that you make in the back you can see how the shaft moves watch for this shaft here to migrate can you see the movement that takes it in and out now when it's disengaged the cone pulley should not turn that back gear assembly and it does not this is when you engage your bullpen on your headstock or your spindle gear and it's direct drive from the pulley to the gear to the spindle the back your assembly doesn't even move the camera moves but the back gear doesn't let's see if we get in there okay that is all she wrote for today guys i don't have the time to make the spindle or the gear but that will be the next installment and i will put in the oil cup holes because i know somebody's going to ask and there's a lock hole in the back here as well to keep this thing engaged or not and that should wrap up the main drive mechanism for the headstock so again i hope you enjoyed that i certainly did thanks for watching hope you're welcome joe pie advanced innovations in austin texas i'm out and for anybody that's curious how i sleep at night with the crack in the original handle well i sleep just fine because i made another one this is the original right here this is the new one the neck is a little bit thinner than this one and i changed it to more of a elliptical than a conical so there you go no cracks on this piece worked out quite well you

Channel: Joe Pieczynski

Views: 38,403

Rating: 4.971787 out of 5

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

Id: NaA1er1-c-M

Length: 40min 18sec (2418 seconds)

Published: Sat Jun 12 2021