Mating the RACK & PINION TIPS #575 tubalcain

hello again it's mr. peak your youtube shop teacher and this is tips number 575 entitled mating the rack and pinion gears together now this is the fourth in a series of four parts about rack and pinion so today in this episode I'm going to tell you how to set it up how to mill it and make it into possibly a useful piece although this is nothing more than a little do-nothing machine to show you how to meet the rack with the pinion into a workpiece in this case just a piece of one-inch thick aluminum I sliced off a little piece of the gear and a little sliver of the rack so that I could talk just a little bit about the working depth and all of that because well I always get right back to math as much as you may dislike it but and I'll touch only lightly on that but the teeth must mesh not too deeply where they bind nor too shallow where there's a chance of stripping a gear or or breaking a tooth off so let me show you the dimensions and way the way to determine that other than baguettes and by gosh this is the whole series of videos that I made on the subject what I'm talking about right now may not make sense to you if you have not seen the other video so check them out there are entire books written on those subjects and I'm just touching lightly here remember the tooth depth and I showed you that in the first video and that's how to determine the linear pitch which is the same as the circular pitch that is the distance between the teeth what I showed you was a repeat so this is new and again these formulas came out of the little black book but the working depth is - that's a constant divided by the pitch and the pitch of course is 20 so doing the math you can see that the working depth is 100 thousands and remember that the tooth depth was 108 thousands I ran out of black paper but that is how to determine the minimum clearance so there has to be clearance the teeth cannot bottom out and using the little formula again with a constant and then always with the pitch we have 8,000 now that says a minimum clearance so I'm really going to provide a little more clearance than that so that there is no binding of the teeth this is the little black book remember there's different versions of this and this is the engineers Edition and there are two pages here with all of that information I show this picture to you in an earlier video but again there's a little bit of clearance right here at the tip of the pencil I thought I'd throw this little bit of information in here and as usually in all of the lathe books regarding again working depth on your gears so when you're setting the banjo on your lathe up against another gear when you're changing gears what they're usually telling you to do for working depth is be careful not to get it too deep or too shallow and the gauge is simply a little strip of writing paper so that when you engage it that is acting as a shim to give you that clearance how accurate is that apparently it's good enough this video or this operation of fitting this up really was more complicated and I spent more time on it than I did on the other videos because there's machining here there's a one inch bore that I had to bore out with a boring head and there's a slot that has to fit perfectly so there is no all slop but yet there has to be a little clearance but you can see there's very little wiggle and the depth has to be right I can back that off that depth has to be just right so that the cover plate here does not clamp down the rack and prevent it from turret from moving so there's your rack and pinion steering and I put a little end washer on here and a collar to contain the rack this is the original project that we did at the high school I've talked about that before a smaller bird press now I haven't done any of this for over 40 years really so it took a little bit of jogging of my memory to remember how I did all of this and a little studying as well but it's it's very interesting to do but there's a little math involved let me show you the original blueprints again so that's the blueprint that I made up I still call them blueprints that I made up Oh 40 years ago or something like that but zooming in on the rack there's the rack now that's not the one that I made here in these videos this is the the one I made at school that looks well something like that it matter correct exactly like that but remember so that the kids didn't have to do all the math I gave them the information right on the blueprint there so they got the the information of the cutter size the pressure angle the pitch the linear pitch and the the tooth depth that's for the rack similarly for the pinion it was also 12 diametral pitch 14 and 1/2 degree pressure angle 13 teeth which means they use cutter number eighth eighth and the tooth depth was one hundred and seventy nine thousand and all the math was worked out for them as well telling them to bore it out one and a quarter inch and that the working depth of the gear is a hundred and sixty-six thousandths and there were the dimensions for them to do all of that work and yes there were a lot of failures on that kind of a difficult job for a high school boy I know you're thinking when is this guy gonna start making chips well you really need this background information before you start cutting but I think this is interesting but I'm gonna take it one step farther and the reason that I cut these into wafers is we're gonna go out we're gonna take a field trip right now we're going out to the shadowgraph and that will blow these way up so that you can get a little idea and of what it looks like and how they mesh and the clearance and any tiny imperfections here will be magnified because I'm blowing it up by ten times let's start on that trip I'll see you momentarily okay we're out here in the other shop at the shear Tamiko optical comparator which I like to call a shadow graph and the one-inch pinion now is blown up to ten inches so that's the size of a small pizza and alpha nose Pizza real where I used to go I'm not sure how well this is showing up but if I can zoom in just a little bit here you can see that the teeth are meshed and right here is the clearance and of course that's called the working depth very difficult to manipulate this because everything is backwards also you can see the burrs that I didn't get removed the Sauber's they would have one of these machines in the inspection department and they probably would have templates very accurately made templates that they could which are like an overlay and they could actually measure the tooth to see if the tooth was the correct dimensions enough of that okay here's the game plan I already cut this off to a working length and that is where I'm going to bore a one-inch hole so I'll rough drill it and then I'll use the boring bar boring ahead with the boring bar to fit to the one-inch gear opinion that I've made so I'll take this out now so I can use this as a gauge here's the setup for drilling and boring the hole I have repositioned the work into what I call the vertical position here and you can see that the gear fits in there nice the pinion just nice really and I already took a light cut off of here to square it up and just remove some of the excess but laying the rack on there now you can see that there is still a little more material that will need to be removed off the top and I want that's the very last thing that I will do so taking that off and this is a 3/8 end mill even though I want a 1/2 inch wide hole if I use a 1/2 inch end mill you know that doesn't really produce a 1/2 inch slot and it'll be rougher than a cop so I'm going to mill this with a 3/8 and then later widen it with the same end mill to the width of 1/2 inch but now concerning the working depth there's a lot of ways to do this and this is not the way we did it at the school but I think maybe this is a better way but I'm going to mill back and forth back and forth until I break into the bore then I'll deburr it and start to take some measurements but the first thing I'll do then is to put this back in after I get the burrs out it'll be a big bird on there and then I can start to determine some of the dimensions and how far I have to go in and in fact what I'll do is I'll touch off onto the shaft and that'll give me the exact position depth wise and then I can get my working depth from there I think that's a good way without doing a whole lot of measuring because I'm well that can be done with micrometer too but I will just dial in the depth then with the knee crank on the milling machine you okay did you see that that the your chips down in there so I have broken through sorry about that I think some of the picture there was out of frame but now there's blurs and this is a one-inch reamer just to clean that bore up just a little bit so that I can get the pinion in there pull that out from this view you can see the pinion the shaft there so what I'm going to do is come in and touch off on the shaft not the aluminum but the steel shaft I'll have to drop the table a little bit to do that but then I have determined that I am exactly on the gear and I can then mill to the working depth which is I got a look again I believe it was right about a hundred thousand so I'll be right back okay the working depth is one hundred thousandths but we have to have a little more clearance there and remember the minimum clearance I think was eight thousandths so I'm going to feed in a total of 90 thousandths in other words I'm going to mill that slot ninety thousand more deep than what it is now after I have touched off and I'll take that in several passes here's how I am touching off I'm right over the shaft now so I'm bringing in bringing the cutter down until it touches and I'm locking the quill I am zeroing the graduated collar on the knee now I want to get this out of here and you can see I left the scratch on it so I know I was touching it maybe you can't but there's a scratch right there that said I am down for the working duck okay the next step is I'm going to widen the slot at the same depth that I'm already at so that it is 1/2 inch wide so I've already already done a layout on each side a rough layout I will mill close to the line and then I'll take a micrometer and I'll measure each side so that they are 1/4 inch and then test fit it with the actual rack to make sure that it's a good fit I'll work up to it [Music] well I'm just about there I'm using a caliper and an adjustable parallel here and I got about one or two thousands to go the rack itself doesn't quite go in but I really like to sneak up on a dimension like this because I can't put the metal back on [Music] [Music] okay that's that seems to mess just fine now the next step is to take a final pass off of the top here I'll deburr it and take off a few thousandths and then it's ready for the cap now here is all I'm gonna do that I've got the rack in place I'm going to basically press it down just a little bit make sure it's fully seated I already checked to make sure there's no chips in there and I'll lock the quill and I will drop the table about three thousandths I think 3,000 clearance for the cover plate is about right I'm just taking a educated guess at that but I think that'll work so it'll be simple enough you that's it I'm done on the mill okay here's the workpiece right off of the milling machine you can see I've got some deburring to do here and here and there is the the slot that I talked about and I'll also run a file just a little bit right here and here because that's always a little bit of a problematic area in terms of burr so I'll do that off-camera and I'll be right back we'll talk about putting the plate on there all right it's bendy bird and roughly assembled here now taking my calipers and this has become my favorite calipers to reach for because of the large numbers on it's just a beauty really this is just a rough measurement because I'm not sure if my calipers are perpendicular here but I'm getting 84 thousands clearance also I could check with a telescope engage the diameter from right here up to a tooth and get the working depth but I think that's redundant just showing you there's different ways of doing it this is the cover plate that's eighth inch aluminum one inch wide and I've already laid out the holes and you can see that's gonna fit on there just nice now I'm gonna drill these holes and tap them lay them out all of that just a little bit differently the one I usually do normally I transfer them you've seen me transfer them with transfer punchers from this you've seen me use transfer screws transferring from a tapped hole in the base piece onto a plate like this so I'm gonna show you a third way perhaps it's the way you always use but it is the way that I originally learned on when I was 16 this is the Stewart steam-engine model I made a machine shop when I was 16 or 17 and we had no digital readout there was no such thing I had never even heard of transfer screws or transfer punches till I was much older we did not have them maybe they didn't had an amendment if I don't know but to transfer and to get all of the screws lined up you know in the cover plate right here and there six of them and these six here on the end and then there's six here my dad showed me how to do it by drilling all the way through both pieces then tapping the holes then drilling clearance holes so that's how I'm going to do this today this has already been laid out I told you so I'm gonna go ahead and drill these holes off-camera on the little camera on drill press and that will be the tap drill size whatever that is I forgot the tap drill size for 632 screws and I always start out with extra screws because I count on losing one so if I need four I start with five if there is if it just so happens that I didn't drop one and lose one I throw the extra way why cuz I have 10,000 of these okay here's the setup this is a three-inch vise I'll have the vise on its side and I will drill all four holes in this set up to the depth allow plenty of depth from your blind holes or you're gonna be disappointed later on and since of course the thickness of this is slightly different than this I used some packing then I'll take it apart drill clearance holes in the cover plate and tap into the thick block you okay now I can rest assure that all these holes are gonna line up now I'll take this over and drill those four rolls out 964 don't take the time to mark things and think about acetyl grab the wrong drill and mistral you don't mind ruining this piece but you certainly don't want to ruin this piece or you'll be pouting until next Christmas and then these four holes of course tapped what did I say 632 okay I have the four holes drilled clearance holes they look good and next I'm going to tap these holes now why did I tell you to drill them extra deep because they're blind holes and then we don't have to fiddle around with the bottoming tap I can just go deep enough with my plug or my taper tap and not have to deal with a shallow blind hole plus these screws are quite short it's what I had a ten thousand of their self tapping to maybe I don't even need a tap oh yeah I do okay I'll finish those up and we're just about done okay now let's see if it actually fits together or was I full of it on my method and this is a method that I tell you if you don't let the work slip in the vise you know it works every time I'll be sure and put witness marks on there which you saw me do so you can always reassemble it in the exact matter hey I got an extra screw that's a miracle now a drumroll please first of all let's put the rack in just to see what kind of fit we got now again you've got to have just a little bit of a clearance but you can see there isn't much one way or the other got a bit of so so it's pretty nice fit now well this fit in make sure there's no chips in there and there we go and that's not binding it's going from one end to the other let me deburr it get that die off of there and put the end caps on and summarize us but first a short story you really have to work with great precision on this type of job or just if you're gonna work so if your name is Bubba or Melvin forget about doing this now why do I say Melvin well I had a student in class and 40 years ago his name was Melvin actually that was his last name he was this was a beginning metals class where we used a lot of hand tools this boy was so rough so crude that even the other kids picked up on this and they call him hacksaw Melvin because he used a hacksaw for just about everything he did and he would saw so fast and so violently that the blades would either shatter or they would actually fly off the pins you don't go across the room so he was kind of an expensive student to have in the class but I for some reason I remember things like that and I had to kind of tell the other kids to back off but it didn't seem to bother old Hacksaw Melvin when they made fun of them but I had to say it listen Melvin mr. Melvin you got a 10-inch blade take about stroll not a two inch stroke and let's cut at about you know sixty or eighty strokes per minute not five hundred strokes per minute you'll get a lot more done and by the way put the blade in with the teeth pointing forward will you well there you have it a rack and pinion steering well we knew some tie rods and front wheels and a few other gadgets and we got rack and pinion steering that was stupid well there we have a rack and pinion this was a four part video make sure you have watched all four parts this last one was just about fitting the two together which is probably the most difficult part of the four part series and you can do that with any pitch I need a metro pitch any size gear but you have to have $10,000 worth of equipment to do this milling machines you need a drill press Neely's you need a lot so I did a five dollar job with ten thousand dollars worth of equipment but some of you might have found this interesting in the back of an old machine shop book there are about 50 projects here is one of them I have considered making that it's more or less a nutcracker but I guess I covered it all in this video well thank you for watching I hope you enjoyed this video series on a rack and pinion and be sure and watch my many other videos that I have and this is mr. Pete saying so long for now I'll see you next time you

Channel: mrpete222

Views: 26,767

Rating: 4.9900866 out of 5

Keywords: machine shop, machinist, tool & die maker

Id: zXrqFZfagrA

Length: 30min 16sec (1816 seconds)

Published: Sat Apr 04 2020