Miniature Engine Lathe - #2 - The Crank Handle

next piece that i think i'm probably going to attack is the cross slide knob now i've heard that this can be a bear to do and i can see why if you look at how it's laid out you have a 5 30 seconds ball on the end 3 16 in the center and a 1 8 on the end on this side and a square through the middle so this is only approximately just over a half an inch long 20 12 13 about 13 and a half millimeters give or take so it's 437 center to center for the ends and the one thing that they don't show you or the one thing i just you know it's eaten away at me i just don't believe that this is drawn correctly this is not supposed to be a spherical feature right here and here on either side that little hourglass shape that you're looking at right there i just got to believe that that's a mistake that is supposed to be straight up and down if this were a weldment you were connecting tubes to another vertical cylinder it's going to look like that but when you have a round cylinder intersecting a ball it does not have that little scalloped feature right there so that's going to be one of the things that's going to throw you off track i'm going to take this into the whiteboard this is a perfect example to show you how i'm going to approach this and possibly give you a little bit of geometry and trig along the way something else i'll think about when you encounter something like this so let's get on the whiteboard and do it okay here's the part in all of its glory and wonderful dimensions black numbers are the imperial numbers the green numbers are the metric equivalent and the red is just the decimal equivalent of the fraction as drawn on the print like i showed you out there the curve that it's shown between the cylinder and the ball is represented as such but this is how it's actually going to look if you were to drill a hole in a ball it results in a flat plane which is exactly what's going on here 7 16 of an inch center to center on the ends this is not centered because these balls are different sizes so the radius on the smaller ball naturally is less than the radius on the larger ball now where do you start how do you do this what's the approach there is all the information you need to do this this is actually not nearly as tough as it looks let's start with the center one 3 16 diameter that's an 0.93 radius knowing that we know that there's a triangle right here actually let's do it on this side it's much better one leg of the triangle it's the radius right there it's a full size cut right there oh 93 we know that this is also 0.93 across so the radius of 046 and a half is right here once you have the hypotenuse and one leg a squared plus b squared equals c squared kicks in and you can calculate this leg all day long same thing on this one radius oh 78 it is a five thirty seconds or 156 diameter the o78 is right here oh 46 because it's the same center line coming across 46 here too will allow you to calculate this as soon as you have this one and this one add them up subtract them from this one which is the center of the center and that will give you this do the exact same thing for the other side oh 62 radius is right here so 46 actually oh 46 and a half right yep oh 46 5. same here allows you to calculate this this will be the same guys with that so i left that on there just to show you what it actually looks like so this dimension will be exactly the same on either side this dimension is called out as the same because 7 30 seconds is half of 7 16. you have all the stack that you need to do this remember that when you cut a circle you can use the radius of the circle as the hypotenuse to figure out the cord and it works extremely well when i do this part i'm going to do this part once i calculate how big this cut is right here i'm going to take a round piece of material i'm going to put two undercuts in it and i'm going to form the radiuses with the two undercuts already done so here's my tool right there i'm gonna put one undercut there i'm gonna put one undercut here and then i will shape the radius in on both i'll show you a neat trick for holding this when you are finishing this piece up they expect you to put a 100 or 2.5 millimeter square hole right in the center i've got a great trick for that you're gonna like it i like it there it is uh i know the drawing is a whole lot bigger than the part actually the entire part is about that long right there that's about the real size of this part so this there's a lot going on it's very small but knowing how to cut the geometry out and figure out what you have the mechanics behind it you have all the information you need go get it let's grab a piece of material start cutting [Music] okay this is 3 16 diameter cold roll steel we're going to make a three point barbell out of that with a couple of undercuts i'm going to do a little bit of radius work on it there will be some filing here unless you have a grinder a wheel dresser and a lot of patience we're just gonna have to try to form this freehand i'm gonna stay connected to the raw stock gonna take it over to the mill pop a couple of holes in it and then we're going to put a square in the center before we part that off so let's do it first thing i'm going to do is face it off [Music] so sequentially i'm going to go for a 125 diameter a 187 diameter and a 156 back here the undercuts are going to be 93 000 each this is really a small part and i'm hoping that when i drill it and put the square in the center that it doesn't bend back here i may forgo the details in the back until after the square and the hole are put in there so i'm going to start with just the front ball the undercut and the center diameter and leave it at that [Music] okay for anyone not familiar with this particular measuring device right here this is called a blade mic and it is used specifically for small undercuts and areas where a standard anvil mic cannot access o-ring grooves piston ring grooves and i'm looking for 0.93 on this cut right here you can see why this bike is just perfect for that let's see what we got 114 21 more so me unavoidably this part is so small my hand will be getting in your way i'm going to do the undercut right here i'm going to finish forming the back of the 125 diameter in the front and the 3 30 seconds round right here this ultimately has to be the same diameter as that but the drilling and milling operations that are going to take place in these areas i think this would compromise it and it would just make it too flexible under the pressure so i'm going to leave this big for now to expedite the process of these rounds you might want to put some chamfers on there to remove the bulk of the material then finish it with a file when you get close shine it up with some memory now i do trust the size of the material it's not going to flex as much as i thought so i'm going to finish that back diameter and a 156 diameter in the rear so for the filing work that i'm doing with these balls the files that i'm using i have taken the teeth off the edge of the file so i can get down in the undercut use the undercut as the reference surface and rock the file back and forth now you can see that the first file in line here has still got sharp edges the side is dull but the edges are still very sharp the second one in line has been chamfered on the edge as well get a reflection on it and the third one is the same so i'll use the second one this one here is the better choice see the teeth do not go all the way to the edge and that should work out quite well let's do it a real good way to accelerate a hand filed radius is to put a chamfer on it with a 45 degree tool to remove the bulk of the material don't get carried away with the chamfer tool you're going to end up with a flat spot on the radius follow this up with the work with the file and check your progress ultimately with some emery cloth to see how smooth and how round your feature really is we're going to go from here over to the mill and it's going to get handled again so no shine necessary right now this part is a very unusual geometry and would be exceptionally hard to sweep or use an edge finder on so i'm using a solid quarter inch drill blank i'm going to sweep across the face of this part until i find a high spot i'll just let's do it i'll show you what i'm talking about try not to snap it off in the meantime all right it's a quarter inch drill blank position just close to the part usually going to line it up and move it in just a hair 2 thou fielder gauge zero out my digital it is trapped and sweep past and see if we've got a good spot okay now going to move in half the pin which is 125. effectively the center of that pin is now over the end of the part you do the exact same thing with the ball itself 218 from the center of each one of the round features o 62 from the end of the round to the center of the round makes for a 280 shift to center [Music] and re-zero the pin should now be directly over the ball the big one in the middle i think i like it you could use an edge finder right now if you wanted to if you can trust being on the high spot of that ball let me do the exact same thing with the feeler gauge and the pin i trust it that much actually let's go yeah i trust it this way forgive the camera angle here for a second guys as soon as you have a little bit of tension get off the part zero the y i'm gonna move in the thickness of the shim and half the diameter of the pin 127 that puts the pin over the edge now whatever your diameter is here in the center move in half of that looking for 0.93 there if the planets lined up this morning when i got out of bed i am on location i'm gonna call that my zero zero spot we're gonna put flats on either side of the center ball and we're gonna put a square hole in that i've been looking forward to that all day this is where we put the flats on either side of the 187 diameter center feature on the crank print calls out for 1 8 side to side and it is a 5c spin indexer so that makes it relatively easy if i had to make two of these the next one i would do and i have a flat on the small 1 8 ball on the end as well even with the 0.93 undercut for cosmetics i think that would work out much better when you add the brass handle to this component moving on to the drilling operation now make sure your center drill is nice and sharp and do be very delicate when you put the center spot center drill in the end you'll see some flex to this part just a little there you go the square in the center is called out as uh 0.100 100 000. that's about two and a half millimeter square this end hole here is a 1 16 through hole and i think uh once it comes back into focus here you'll see why a flat on that end ball would be better right now it's a very sharp edge i'm gonna go with the same sixteenth drill through the middle then i'm going to put a one that's i'm not gonna go with a hundred i won't approach it to a hundred this is about an o ninety five drill which is just a little bit under nice and clean part is still in the 5c indexer and i have a small file in my drill check i am not going to turn the machine on it is in back gear it is in the lowest range and by working the quill up and down i'm going to file a hole in the center of that that's going to accept a 100 square gauge i'll film a little bit of it but i'm not going to film the whole thing because i can promise you this is going to take a while the file is bigger than the hole and the file is positioned at 45 degrees so by applying pressure to the rear to the front left and right i can adjust the size of the square accordingly i'm going to be real delicate with this first couple of passes so i don't compromise anything the file is naturally going to find its way to the high spots on the circle so by putting pressure x and y positive and negative it's going to find its way through now you're going to see some flex in the file right there and i can assure you that somewhere in the edited footage the file pressure is applied evenly and it is a tapered file so be real careful before the whole body of the file gets through this hole once it does get through you can apply a lot less pressure and let the file do the work and ultimately you'll come up with the size that you're looking for i did make a brass gauge to check the size and that square came out to around 104 very pleased let's get back to the lathe and finish it finish length of the part is 577. i'm going to go partially way through it finish as much of the rear radius as i can then cut it off 577. here we go so [Music] i think that looks pretty close to me let's part it the rest of the way off take care of that by hand all goes well this should fit in a 3 16 collet risky but it should fit okay guys moment of brutal honesty here when you make a part this small i mean that is an awesome looking crank handle okay but when you edit something like this when you put this on a computer monitor it looks like this needless to say not acceptable i'm going to touch this up i'm going to make a form tool real quick and it's really it shouldn't be all that bad i'm going to make a split bushing to hold this thing and i'm going to make this shine like it's chrome plated because close enough on something like this just isn't good enough that is tiny i'm also going to throw one of these on it just for laughs let's see how fast we can get this done i'm going to take a quarter inch high speed square tool bit and we're going to make a form tool to correct that little knob this little guy here because that ball under magnification is just not round enough one in the center is good the one on the end is good but that five 30 seconds radius on the end is just not cutting it this morning tip of the tool is blued it's locked in here because it's just easier if you're going to do a form tool just you have a nice registration surface for the radius gauge you can position it on the tool blank accordingly i'm going to work from the toughest feature back and that means i'm going to grind a nice radius on this and then i'm going to determine how deep it is at a later date right now the radius is the most important part so i'm going to get in the way of the camera here for a second you can see the line that's drawn on that this end of the tool here is much deeper than the allowable undercut in the tool or in the crank itself but after you grind the radius on you can nose this back and i'm pointing at this area right there so i'll grind the radius in here first to get a good profile and then i will adjust the nose of this back so it fits in the undercut on the part i'm going to rough this out on a pedestal grinder then i'm going to come back and finish it with a cut-off wheel on a dremel tool because you get a lot of control that way all right after about 15 minutes being extra careful with the cutoff wheel on a dremel this is what we've come up with and i think that's going to do the outside and inside radiuses quite nicely very mild relief on it a lot of primary or secondary relief but the tough stuff right at the top this should give us a nice profile i'm going to do the nose of the part first and i will grind this back for the undercut and hopefully come up with a ball looks like it's chromed let's do it we're going to do the outside part of the radius outside radius first and the form tool is as ground you got to be really careful here i'm going to put some sharpie marker on it so we can see the contact i'm going to come in with the od first and then bump the carriage forward to clean up the radius and i'll adjust both as i go along be real careful with this the amount of contact you have on that radius tool is probably equal to or greater than the cross section of that 0.93 and a little too much pressure could just snap it right off you can see the black left over from the sharpie those are low spots on the ball i'm going to try to work them out until they disappear or become superficial enough to come off with emery okay after about 15 trips back and forth to the pedestal grinder and a whole lot of looking down through a jeweler's loop i think i got the tool ground to where i like it i wish i could get an overhead shot but i cannot i'm coming in from the back of the ball on this side so the tool is in the undercut and we'll see if we can make this thing look round here we go let's get overhead see if i can get you a better shot of that there it is all right there's a couple of bumps on it but we're going to take a smooth file and round that off and polish that thing up like a trailer hitch nothing else we'll do i'll be back all right a little tip for you when you are trying to bring something to a very bright shine and it may have radial scratches in it hit it with a sharpie marker and as you file or use your sandpaper over top of the part the low spots will be black stripes like you see here now that is incredibly superficial but when it comes to a high shine that will be a distortion in the reflection and it will stick out like a sore thumb so although this is incredibly small uh devil's in the details right so i'm going to continue with this i'm going to shine it up and show you what it looks like when it's done but remember that tip that's a good tip black sharpie marker on the part as you file it or sand it or whatever the low spots will continue to show up as black lines like you see here and that is just unacceptable with a little tlc take your time that's what you can achieve you can still see some mild scratches in the 0.93 part of that but as far as the reflectivity of that ball is concerned i'm not complaining about that that is a million times better than it was and that son of a gun is tiny i'm gonna spin this around and polish up the other side just because i can't have it looking like that that'll make the brass crank for it damn that's small all right no crank candle is complete without the actual handle part itself this is brass and this is one of those shape to fit i like those kind of dimensions shape to suit love it so eighth inch diameter brass i am going to stick this in there form this up by hand and the first thing i'm going to do is take a parting tool and make a witness boundary mark on it so i know basically where everything is so it's visually appealing this should be relatively quick and i will back turn this so the eighth inch material will be in the collet here i will plunge this undercut and feed it out and then part it off that way you don't have to worry about sticking it back in the machine after the fact because it's going to be pretty shiny when it drops off let's do it first thing we're going to do here is face the front off as a reference surface going to bring the party tool in and visually align the outside edge of the parting tool with the face move it in the length of the handle itself that's 375 or about 10 millimeters bringing in a large radius tool working back and forth now to give myself the profile i'm looking for and as i'm moving it back and forth i am diving it in doing that reduces the chance that this part is going to come up and over that tool i'll form the ball on the end of the file and the transition between the large radius and the major diameter of the material that will blend out with a piece of memory you'll see here in a second so you get that elliptical bell look and shape on the end this is one of those personal preference things as it develops you machine it however suits your fancy now if you have to make three of these and you want them all to look the same well you might want to take some numbers if you have a digital readout that's easy to do just pay attention to the digital pay attention to the dials and anybody that's ever polished anything to a high shine knows that even the smallest of scratches looks monumental when the thing is glass clean and one of the other frustrations is chasing a scratch that's actually a reflection from some feature on the machine i've learned that the hard way several times move it out make sure there's no polishing compound on the collet and come in and back turn the small diameter that's going to fit down inside the steel component of the handle assembly pay attention to the outside component i'm looking at a jeweler's looking through a jeweler's loop right now as this diameter gets smaller the only way to check it is with a blade mic so that's what that was just there as this diameter gets smaller the shear mass of the end of this part although it is tiny will have a tendency to want to whip so if that starts to happen be careful about how much surface contact you have or how high the rpm is if that happens you'll get a taper in this feature and it will be smaller towards the outside of the part and bigger towards the collet okay now when you're making this it's called out as a 1 8 diameter all the way down but remember the small end of the crank is 1 8 diameter but when you pop a hole in it it becomes much smaller where the land is so if you want this to look relatively decent put a chamfer on the back of this or turn this part down right here to considerably smaller i'm going to put i'm going to turn it down and re-polish it because i know what it's going to look like when it goes on and i'm not going to be pleased as you turn this back diameter down it is going to get longer so if that's something that you still like the way it looks by all means leave it polish it up and call it a day but if you go back in there with the radius tool be careful since it's a smaller driving diameter the material is going to want to climb up and over that tool at a greater risk level so be careful measure the thickness of the end of the crank where the 1 8 ball is that you just did and this stem needs to be that long maybe a little bit longer because they recommend peening it over but this is so small i guess that is up to you how you're going to do that mine comes out to about 110. will register the parting tool on the inside of the large diameter move it down 110 part it off as with many of the small parts that i do i am looking down on the top of the parting tool with a jeweler's loop and from the turning operation when i reduced that back diameter not the small diameter but the cosmetic diameter it did leave a crown burst so if you see some chips flying off i know the comments are going to be well that's a little bit more than registering now i'm just removing the bur as well and i know that the tool i used to put that undercut in there had a 20 hour radius on either side so you'll see the radius go away here in a second right there and i simply shift over however long you want it since the outside of the parting tool is now a zero surface a simple shift and you're done camera is going to cut out on the parting operation but you'll take a look at the assembly here shortly [Music] well i hope you enjoyed watching that as much as i enjoyed doing it i only have to make two more of these handles not the steel part the rest is aluminum so it's a lot easier this is probably the toughest one this is the cross slide setup but two more of the brass sections out on the end you know if i get real cocky i think i might just figure out how to make that swivel so your hand doesn't get a blister when you crank it anyway thanks for watching guys hang in there until next time stay healthy joel pi advanced innovations in austin texas i'm out shut up there you go holy cow that took a while all right we're back

Channel: Joe Pieczynski

Views: 45,209

Rating: 4.97192 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 machines, scale models

Id: mad99eyXpJE

Length: 38min 36sec (2316 seconds)

Published: Sun Jan 17 2021