Mini Dials for the Mini Lathe

in keeping with the fabrication this little lathe this is giving me an opportunity to try or not try but actually practice a different approach for cutting a specific feature now if you watch the production of this little crank right here you saw me do the inside with a square file held in a drill chuck and activate it up and down like a die filer it worked out very well putting the dial on this is going to be a whole different animal this square has to be very concentric very true position to the outside or when you turn the crank it's going to look like you know it's going to run out period it's not going to look like anything it's going to run out the dial on the tail stock has the exact same square drive feature the hand wheel on the carriage has the exact same square drive feature and so does the lead screw for the cross slide i'm going to make a brooch this morning really quick for this particular feature right here and for the other hand wheel naturally and for the little brass style that i'm going to put on that guy right there quarter inch diameter high speed steel drill blank i'm going to hand grind it real quick and then i'm going to put it in a spin indexer in the mill and i've already done a video on this called can you grind on a mill and yes you can so i'm going to do it again real quick before i broach out those components let's take a look my grinder is set up with a coarse wheel on the left and a finer wheel on the right i will take the majority of the material off of this high speed drill blank on the left hand side dunking it in between because that is getting quite warm trying to keep it concentric get it over on the fine side and get it down to a manageable diameter that i don't have to grind too much off of on the mill i'm gonna load it up in my spin indexer the other side of that is a much larger square this is going to be about an eighty thousand maybe about a two millimeter across the flat square using a norton cup wheel and a homemade arbor i'll hold this entire assembly in a three quarter collet in my mill that's all it takes quarter 20 screw recorded collet here we come i'm going to spin this at about 1800 rpm which is a little slow this wheel can go to 5800 rpm spin indexer in the vise raise the heel of the spin indexer just a little bit to put a mild draft angle on the brooch that way it doesn't drag all the way down it cuts on the front just a little tiny bit going to reposition the camera here we're going to look at it from underneath and it's okay if it's running out like that you see the eccentricity on the outside of that wheel it's not a problem the face is true and that's all that we're cutting with these are about 10 000 of an inch deep passes here and i'm just going to run it down till i know it will enter the pilot hole that i'm going to put in the material comfortably and yes the machine is thoroughly draped at this point every conceivable surface is covered up you don't want this grinding dust flying around your machine once you know you have all corners nice and sharp i'll lock it off in a specific position and i will use the edge of the wheel to make a small hollow grind on the nose of the tool right there done looking for an 0.96 final square this is a setup piece of brass so i know that when i get to my real dial i know what my readings will be on my digital readout and the easiest way is to just poke into one corner and walk it to the next corner to the next corner to the next corner and i have a lifelong habit of always turning my dials clockwise so if you see me back out that's what i'm doing there's a little look for you with a dental mirror makes a nice feature but it's got to fit the mating part right so make sure you double check everything and it doesn't take a whole lot for it not to go the adjustments here are about one thousandth of an inch per surface until it just sneaks in make sure whatever you make your brooch from that it's large enough in diameter that it doesn't flex under the load of the cut i'm going to prepare the stationary and movable dials on the same or actually on different ends of the same piece of material using a common piece of material like this or an extended piece of material like this makes it a lot easier to handle the final product when the final piece is small stationary dial is a simple turn to od with a reamed hole through the center and the movable dial will be basically the same as this but we're going to back turn a small diameter on it so that it looks like the lock nut that you would find like on a mill table the bearing make sure the gauge pins fit always break the od where the cut terminates right there if there's any flare it could affect the concentricity of the opposite side of the plank i'll do the exact same thing turn it to the same diameter so the diameters match that assembly drill and ream the inside and plunge cut the back with the parting tool make sure your parting tool is rigid enough so that it doesn't flex under the cut and that it's ground correctly to give you a nice square corner this little counter bore right here is the controlling feature that will terminate the lead screw and square drive features this is critical this depth right here it goes one way or the other it is very possible that the assembly will pinch and not turn and once you're happy with the diameter and the depth deburr everything move on to the back turn and take it over to the mill give you a quick look at the setup here if i were doing multiples of this piece i would have a stop on the stationary vice jaw to hold the v block in place as well when you put the parts in the middle make sure that you indicate everything for a concentric relationship in the features this is the broaching operation for the movable dial and there is no rotational relationship required here this dial will spin so this square can be in any position but for sizing purposes it's always good to have your broach in line with the table so your x and y moves will give you nice straight edges now this face is so small that a visual alignment here is fine i lay a scale across it and i look at the scale in relationship to one of the jaws and when i'm content that it's true we go for it always make sure there's sufficient room underneath your tool that you can put your mating piece or a gauge in that's really you know quite a shock when you're working on a critical feature and you need to move the table because you can't get the gauge pin in we've all been there i know i have and this is a through broach operation that is the critical counter bore that you saw me bore in the previous operation in the lathe all goes well the lead screw goes in and the round diameter engages the bottom of the counter bore same time the square goes through that is a control surface extremely important oh moving on to the stationary dial make sure that the concentricity is there since there's no stop on the v block these are the two anti-rotation dowel pin holes that will make sure that this dial does not spin as the lead screw spins through the smaller center bore and i place these by i think next time i'd place them i place them a little bit closer to the center because they are just about tickling the od of this part this part was any smaller this would be a scalloped hole and that's not a good thing i'm doing it much deeper than it needs to be so the reamer doesn't pack up and this will be parted off in the lathe after the fact so this is going to be a very small washer but this is just a much easier way to handle it o63 reamer finish off both the holes and the secondary work on this part is basically complete this is the stationary index dial and it does require a single index mark positioned 180 degrees of post from those two dowel pins that i just drilled now that surface right there is facing the camera and not facing me so this is going to be something i have to fiddle with with the mirror so it's easier to film than it is to do this is a 90 degree high speed steel brooch i'm coming down in the quill with it and it's not going down past the shoulder on that part although it looks like it is it's not it's staying well shy of it i'll creep up on it visually from the side i only want to go about five to seven deep make sure that if you're going to do this that you do this at the same time you drill those two holes because that marks got to be got to be opposite those two holes for correct positioning at assembly this brooch is so rigid and this material is so soft that i literally can't even feel whether or not it's cutting i have to see if it's cutting and when i get the depth i'll put my finger on the back side of it just to see if there's any deflection or movement or contact interference at all and i can tell you that i didn't feel a thing i didn't feel a thing this groove will be filled with a black lacquer right assembly so you can see it as long as it's steep enough to accept the lacquer the feature is good enough try to make it the same width as the lines on the dial just for visual cosmetics no interference back in the lathe for the parting operation i'm setting my tool by dragging my razor blade across the face of the tool and waiting for it to stop clicking against the outside of the parting tool zero out the digital move in your required amount i'm going to make a very superficial plunge cut here come back with a 45 degree tool and chamfer both of those exposed corners and finish the parting operation this is the stationary dial and i'm using a catch tool that a viewer sent in i'll see if i can put a link to that particular tool in the video description handy little thing to have only because this is a scale model and for no other reason i'm sure there are 10 different ways to do what i'm about to do but i'm going to knock this out in the most backwards fashion i can possibly think of because time is of the essence here and i want to get through this i have taken the diameter of this particular part multiplied it times pi coincidentally to come up with the circumference that particular length divided by 25 is what i need to do on the od of this particular wheel right here you cannot get what you need with the graduations that they give you that being said white packing paper from the very beginning to the very end is one complete revolution of the face of that spin indexer i'm going to cut a piece of this off strip it all the way back to about a quarter of an inch and tape it on and then i'm going to visually use a pointer and stop on each one of these lines to give me 25 even graduations about the diameter of that small brass dial and if you don't think i'm serious there you go excel spreadsheet gives me all the numbers i need and i laid it out with the 24 inch burner so a little bit of overkill but i can probably assure you that these lines are going to be very close to accurate well as accurate as my eyes are so let's shave a piece of this off tape it to the dial put some graduations on that little brass thing there you go these cuts are going to be incredibly superficial and the rotation will be locked right there let's put in a count set the machine up put some graduations on that little guy this is the final setup i will be using this is my pointer mechanism here on the side i'm just going to rotate this by eye until the bottom of that tool lines up with the line on the paper and i'll bet you that it comes out pretty close you think about a projected error when you get down to the little diameter that we actually cut down here versus the space between these lines those lines are going to be pretty fine so if i can get these lines pretty much spot on that pointer we should be in good shape i'll take a few test cuts at one location because there's no guarantee it will repeat no i mean it's going to repeat as good as my eye i am using a snap tap internal threading bar to do this so these are 60 degree v-grooves that is a very fine insert let me spin that around show you that that's the insert that i will be using it is visually lined up on center with the blank and all the cutting will be done i guess maybe i could do it around the front let your watch progress as it happens right about this angle here okay let's get on the tripod finish this spindle speed is about 1900 rpm for this operation i'm going about five to seven deep all the burrs and everything will be shaved off on the lathe after the fact and these groups will be filled with a black lacquer to match the stationary dial this is accelerated footage foreign that is incredibly hard to film as you can see depth of field is really narrow all right let's pop it out clean it up take a better look at it let's see if i can do this with the camera right in my face these are o62 long dial pins excuse me 062 diameter about 1.2 millimeters excuse me 1.5 millimeters you can see the index marking the top now this is the dial that does not move the lead screw through from the back put the new one on okay get back here here we go let's try that again now this guy has to be driven by this screw itself so that's got the square brooks in it from before you can see the lines as the screw turns that knob turns and forgive me for not putting numbers on there i just barely see those lines i will ultimately fill them up with a black lacquer and wipe it off so any any cutter marks or chatter or whatever will go away but you can see how nice and uniform that that turns out doing it that way that is only about a 5 000 steep scratch right there that is very superficial there is a rather critical stack dimension that needs to be hit or when you tighten the crank down everything will pinch and nothing will move so that dimension has not been established yet and that is brought in not only by the depth of the square cut in the graduated dial but the thickness of the stationary dial that is all adjustable let's put this on my goodness that is small the tolerances that i used on my dials are a little tighter than the tolerances they give you for these knobs there we go that's squeaking and howling here in the back it is an incredibly windy day here in texas and that is the big garage doors jumping around and the roof vents and they are even cinched down as tight as they can get those roof vents they're still jumping there you go that took an awful lot of time it took a full day to do that in case you're wondering what the real time was here that's a full day worth of messing around generated a couple of drawings and yes the handle is still loose i'm not going to cinch it down because i don't want to gall anything i generated a few drawings made all the parts made the brooch and those lines should give you an advancement of the carriage excuse me of the cross slide one thou two thousands coming off the diameter for each one of those lines 25 graduations 40 threads per inch on the screw and that's about as good as it gets right there that's as good as i'm gonna get it that's all we got guys thank you very much for hanging in this is a fun project and i appreciate all the comments and feedback i hope you're well wherever you are in the world let's hope 2021 is going to be a great year so far this has got me distracted to the point where i almost feel human thanks for watching joe pi advanced innovations in austin texas i'm out you

Channel: Joe Pieczynski

Views: 40,301

Rating: 4.9731145 out of 5

Keywords: Joe Pie, JoePieczynski, Advanced Innovations, advanced innovations llc, how to, machine shop, shop tricks, shop hacks, shop techniques, shop tutorials, PM Research, mini lathe, scale models, graduated dials, indexer, odd number divisions

Id: gx8OQQteCxY

Length: 24min 46sec (1486 seconds)

Published: Thu Mar 18 2021