DIY Gear Hob Part One

all right we're going to make an involuted gear involute gear for an Atlas 618 changed gears I know from research on the web that it's a 24 pitch and it has a pressure angle of 14.5 degrees it's very important that you understand each and the pressure angle of the gear you wish to reproduce so if you look you don't have one that you can't find it on the web take your calipers get an outside diameter the outside diameter of this one is 1.9 7 over top of it puts your number of teeth this one has 44 teeth add 2 to it and then divide it and you'll get 23 point 3 5 0 so your pitch of this gear or your demetria pitch is 24 you round it up now when you do that with your gear if you don't get anything even close to a whole number it's going to be a whole nut and even number then you probably have a metric gear and in my description for this video I gave a link to a guy's website he does a really good job of describing how to figure out for modular type gears the metric system so you could go take a look at that and now the pitch angle the pressure angle sorry the pressure angle is either usually probably either 14.5 or 20 when they're looking for strength of durability they'll go up to a pressure angle of about 20 14.5 gives you a little plus or minus on your depth and it's a good one then if you don't have any idea what your pressure angle is make your make your cutter a 14.5 do your plunge cuts and then take your cutter that you've and then made it with your gear okay and you should be able to tell if it's going to make correctly if it doesn't then you can take a 20 degree bit and redo your plunges to the 20 degree and that's probably what you're going to find you need a lot of discussion about these Hobbes and what they can do and what they can't do anybody that I know that's actually made one and actually use the gears they've found out they work quite well if you see my thread cutting attachment that I made the video on that one those were all hobbed with a gear lob like this except a little smaller so what we're going to do today is we'll make a hob then I'll make a gear and I'll make the gear with this store-bought Atlas gate thus assisted this is the gear that came with my Atlas and we'll put them under the microscope we'll run them side by side take a look at them then I'll take it out from under the microscope and I'll put the gear that we made on my lathe and I'll run my lathe and you can get an idea of how they run and what they sound like when you're done that should give you a pretty good enough information to make a decision whether you want to make a hob or you want to go with this a single point cutter I look at it like gasoline if most cars can run on regular gas maybe 10% of the cars actually need premium so if you need premium you might want to go out and buy a set of cutters and do it a different way but if you're making gears I made a lot of stuff with these hobbs they work pretty good I like them but do things to make the Haab we need to know we need to know the circular pitch or the distance between our plunge cuts that we're going to make to make this hot now to figure that out your circular pitch equals three point one four six over your de metrio pitch which in our case is 24 so that equals point one three one zero eight three three if you use in the calculator so we're going to get use this here so that's going to be our distance between cuts now we need to know when we make our plunge cut how deep are we going to go with it all right and you figure out how deep it is by putting 3.40 over your de metrio pitch again and that equals 0.14 and one six six six because if you're using a calculator we're going to go to 0.14 so that's what we need to get started so let's go into the shop and start making this table all right we're going to start off by cutting off a half inch of water hardening drill rod at two and a half inches and that's how we'll make our plug [Applause] all right let's start off with our facing this drill rod stand for the edge a little bit we're better built fit alright tip it over to the mill alright what we're going to do now is we're going to cut a little quarter inch wide relief in the end of the hob so that when you put it in your holder it's going to you can put it a set screw on it and the test screw will hold it and if you get any thing in the metal if your your heart will still come out of the thing it won't get caught up on the game and there that's going that should do it right there all right so now we got to get our cutting bit we need 14.5 degrees so I built this little wooden jig and you just simply put your feets in here like that and keep going side to side this one's about ready now your table set at seven degrees so that you got a nice rake on the side of it you want a 29 degree included angle so there's your 29 degree concluded angle [Music] and now when you've done [Applause] [Music] taking India stone or a diamond stone or something and then you can just run the top of it across that like you would your graver or anything like that that you're sharpening and then I just run the sides just a little bit and then give it a test out your cutting edge on your there you go all right you got a good cutting edge there okay just wanted to give you a good look at that tool post holder holds the tool upside down on the rear side the first hob I made had a 20 degree bit and I didn't have any trouble with the plunge cuts with that but with the 14.5 bit I had all kinds of troubles and I I messed around with my bearings in the head and the tail stock I tightened the Gibbs up I used a tail stock with just messed around with that tool stuff I squared the tool with a head I round with feeds and speeds forever I tried cutting it like you would your threads and that didn't really work either and all of a sudden it dawned on me that people use a cut-off saws and that's a plunge cut by reversing it on the backside so I made it and sure enough it as you can you'll see in the film it just plunges in there quite nicely and I liked it so much I even made a bigger one and that one's for my atlas and and I got cut off blade on one side and I got the regular quarter inch tool bit on the other side and I like them a lot and in the video you'll see them so you can keep that in the back your head in case you want to make one okay I've skin cut and i put dyke' them on here and I'm starting my a plunge cut there's the first one there [Applause] ah [Applause] [Applause] [Applause] okay I'm going to start the first plunge cut [Applause] all right there's the first one cut I'm not going to show you all of them I'll just make them enough show you parts and pieces [Applause] [Applause] all right there it is there's your five lunch cuts that's the hardest part of this old job and they're done now and they look pretty good now but we'll measure I'm going to take a little back this off a little bit and take triangular file and just kind of knock the edges off [Applause] all right [Applause] right now I'm cutting the relief on the backside of the hog and it'll take a while and I won't bore you with the whole thing as I get near the end I'll come back on okay we finished the back relief take them tamper the edges okay before we go over to the mill I wanted to show you this graphic representation of what we're going to do when we get over there we're going to put a slitting saw in there and we're going to foot cut five slots notice that the slot the cut is just above the center the center line of the hub then we'll rotate it 90 degrees and then we'll use an end mill to cut it off like that these are our cutting edges here and we're just going to cut some relief behind them this is just a graphic representation this is you can kind of do this mostly by eye the only thing that's really critical is this slitting saw has to be right on center or slightly above the center and then you'll get the proper rake on your on your cutting edge okay let's go over to the mill and do this okay this next move is really critical you get your hob in here with your slitting saw bring your Cindy's flipping sauce so it just touches off the top of the hob then move your y-axis away from it okay and now you're set and ready to make your slits [Applause] alright we're cousins slits in the slots in that table right now cutting five of them this will take a while so I'll stop every once in a while and just give you a look and see how it fits and see how it's going all right that's the end of the slitting saw cutting so now we'll get there to that get anvil in there and finish this thing up [Applause] all right now we're using the end mill to cut the relief on the cutter edge this will take a while I'll come back and forth to show you what's going on [Applause] they were making our last few Pat's here take it off you they were starting a hardening process on it on the table using map gas to do this with propane I've done it with propane before I just happened to have Matt we're going to heat it to Cherry now we got a can of water sitting right there punching it in the water okay that's that okay here's a finished look at the hob get an idea how it went and we're ready now to go over to the mill and start making our gear

Channel: robertt4522

Views: 256,287

Keywords: gears, gear hobbing, machining, lathe, mill, change gears, Atlas lathe, lathe change gears, involute gears, spur gears, gear making

Id: bQXW5DP4ZSc

Length: 18min 53sec (1133 seconds)

Published: Tue Aug 08 2017