Let's Make a TAP FOLLOWER!

hello Internet my name is Quinn and this is blondie hacks one of the tools I get asked most about in my comments is this little guy this is a shop made a spring-loaded to tap follower and I have some improvements I want to make so we're gonna make another one and this time you get to watch let's go let's start by taking a look at what a tap follower actually does when we're tapping a hole we need something to keep the centerline of the tap on target and so taps generally have a Center in the back of them and that's useful if you're using an open back tap wrench like a greenfield style or if you're just using a regular wrench on the tap itself and very small taps will have a point on the back instead of a typical Center because there isn't physically space there for a center so you have to use these with something that has a negative Center on it but if you're using a tap wrench such as this starett it has its own Center and it completely encloses the back of the tap so it doesn't actually matter what type it is but regardless the spring-loaded tap followers role is to go in the back of the tap and you can use it on the mill you can use it on the drill press and you can even use it on the lathe and you can lock whatever quill is pressing on the back of the tap and the spring-loaded action of the tap follower keeps the tap aligned and allows you to move it in and out so that spring-loaded point there is is really the key and the other key is that the entire device is very concentric and so it will keep that tap on the center axis of whatever machine you are using it in this is a shot made tap follower that I made several years ago so let's take a look at how it's built and look at some improvements that I'd like to make this is a pretty typical design the front of it unscrews and inside we have this sliding pointer here and then behind that pointer of course is a spring that makes it all work now the weakness of this design is that it relies on the the center portion of the pointer they're doing all of the support because while you're tapping there's side loads on this pointer and ideally you want the front narrow portion of the pointer to be supported as well as the wide portion at the back so there's two points of separation that are spread apart a bit but to achieve that you need a very concentric bore on the tap follower in a very concentric opening in the cap and if the cap is threaded on it's very difficult to achieve that and for some reason I also decided to make the tip and this guy out of a replaceable piece of tool steel that is threaded into this piece of mild steel and that also makes it difficult to keep it concentric because threaded fasteners generally don't hold concentricity so this whole design here is pretty over engineered and because of that I had to open up the hole in the cap in order to maintain concentricity so I lose that second point of support I also don't like how thin this pointer is so I want to make one that's beefier has more lateral rigidity the other weakness of this design is that because everything near the end is threaded when you're using a spring-loaded tap follower there are spinning forces on things the pointer tends to catch the tap and turn and so it has a tendency to unthread itself and that's the cap and the pointer sometimes come on threaded while you're using it which is annoying and the other flaw and this one is I don't know if you can tell on video but that pointer is actually slightly bent because I heat-treated it but didn't I don't have a surface grinder so I didn't surface grind it after the heat treating and as often happens the heat treating warped it slightly so we're gonna fix all of that with this new design and this guy has a single piece pointer so there's nothing to unthread and the real key to this design is that the hole for the pointer is in the solid end so the cap that unthreads is in the back and I've also added a small negative Center in the far end so that the pointer can be removed and reversed for using with small taps and you'll note that the design is asymmetrical because generally if you're using a very small tap you don't need as much travel on that pointer so the one-piece pointer and the one-piece design if the business end of the tap follower should allow us to achieve excellent concentricity and thus have those two points of support against lateral loads which should make for cleaner and straighter threaded holes so we'll start by making the main body and here's a trick to find out exactly how much stock you should cut so measure the length of my jaws here so we've got 1.5 inches there and then bring your parting tool in as close as you're comfortable to the stock and then measure that distance there we got another 0.3 of call it point 5 inches there we add an inch for metallic or the god of machining and we end up with 6 inches of stock which we can mark and then face this guy often know that when we pull it out we've got a nice firm grip with our jaws so we'll start by facing the end as is tradition and we are going to need tail support for the turning that is to come so we'll throw some anchor lube on there hashtag not sponsored and punch a number two Center right in there and now we can pull this guy out to our mark confident that we have enough room for the parting blade and for the full dimension that we need on our part and now we can start turning this guy down to dimension so I'm using 12 L 14 steel here you could use mild steel you could even use tool steel if you're up for it whatever works for you it there's not a lot of stresses on this tool honestly so it's pretty easy going as far as what material you use so I'm just turning this guy down to a 500000 again the dimensions on this are all pretty flexible I would suggest making the outer diameter of the body something standard like in the imperial case 500 thousands because that will allow you to put it in a Jacob's Chuck or in a collet and on the mill in particular being able to put it in a collet often saves you a ton of vertical real estate so I'm shooting for 500 and I lined it on four ninety nine and nine tenths in some shops that gets you fired in the plunging axe shop that gets you promoted now we're gonna make that inner boar and rather than disrupt the part in the chuck I'm going to bring in the steady rest and that will provide some lateral stability just to keep it from wandering off course during the drilling because we do have a lot of stick out there so there's going to be some flexibility so I bring in the steady rest here and set this guy up on my to-do list is to do a complete rebuild on this steady wrist as with many budget machine tools the accessories like this are pretty mediocre but this guy will get the job done for us and I'll check the run out on the far end just to make sure I haven't distorted anything with the steady rest and it looks good making a very deep bore with a flat bottom is actually very difficult so instead I've accounted for the hundred and eighteen degree drill point in my drawing and fusion 360 will tell me how deep I need to go with that drill to create that a little bit of a shoulder so it'll just be sort of like a fudge area that is inside that bore so you can see we need to drill two 2.83 inches but one of the limitations of small lathes like this is they have limited quill travel on the tailstock so instead what I'm doing is just marking the depth on the drill itself and not using the quill markings and this is obviously less precise than using the hand wheel and the markings on the quill but I've just allowed 40 or 50 thousandths of wiggle room in the design so that I don't have to be super precise with this design and I don't risk punching through to the far side this particularly advertises a whopping three inches of oil travel on the tail stock but the anti-rotation tang on the taper the holes of the Jakob Chuck actually costs you another half an inch so yeah these are the little things that are not in the brochure but we can make it work by marking the drill so I drilled out the entire bore to one size under a quarter inch because that's the size of the pointer hole at the end and then I drilled and reamed the body out to five sixteenths because that's the size of the larger inner bore and then once that's done then I go back in with a quarter inch reamer and finish the hole at the end so I end up with a quarter inch hole and a five sixteenths for both very concentric and precisely dimensioned next we need to make the smaller diameter for the threaded portion where the cap goes on and here's an easier order of operations do this before you do the drilling I just show it while you still have the center in place I didn't think to do that this time so I'm going to do it with the steady rest in place so I've just set my tool on the end of the part and then I'm counting back the 430,000 this and then I rezero my indicator and now I can start turning that shoulder down and I'm getting some chatter here so it seems that my steady rest isn't quite tight enough so I snug that up a little bit and now it's cutting well and now I'm cutting those threads using my tail stock dye holder if you don't have one of these you can also just use a die wrench and hold the die wrench square by pressing the face of the tail stock quill up against it that works just fine as well and we'll deburr that guy while we've got it set up here next we're gonna mark where to part this guy off and I started at the parting operation but we're working pretty far from the Chuck here and it's a hollow tube so it's not very structurally sound so I was getting some chatter so this wasn't gonna work very well so instead I brought in the tailstock and now you don't normally want to part with the tail stock in place but what I'm doing here is just going in most of the way and getting through the tough part and then once I'm almost done then I pull the tail stock out for safety and Yahtzee and a little deeper on that and Bob's your uncle I got a pretty good finish with that parting blade so I'm not gonna bother facing the end but you certainly could flip it around and face that if you wanted to next we're gonna make the cap shown there in yellow and once again that involves a fairly precise drilling operation and once again I've just marked the drill point in the drawing and taken that measurement six one six nine so I can hit that guy with the drill so here's an easy way to do that I just use my machinist scale and bring the drill up and then I use the tailstock coil to measure the depth from there and then the thickness of the machinist scale basically gives me a margin of error and then I tap the threads for the cap and you'll notice that I'm cheating and using my old tap follower here to make the new one if you don't have one of those there's other ways to do this check out my video on using taps and dies on the lathe for lots of other approaches that also work so I've gone in with a taper tap and I'm going in with a bottoming a tap to get as many threads in there as I can and we'll do a test fit of the body into our cap here and if you're an experienced machinist you know this isn't going to work very well there's always going to be a gap there and that's because it's basically impossible to cut threads right to the base of a shoulder so we're gonna make a little relief so here's a quick and easy way to do that I just go in with a 7/16 drill which is the size of my thread the major diameter of my thread I'm gonna send that in 100 thou creates a little counter bore there and now our cap threads on very nicely you could also do that with a boring bar or other fancy methods but just using the big drill works and now I align the far edge of my parting blade with the end of my part and put an indicator on there and count in the length of my part that I want a little sanity check with the caliper make sure I'm in the right spot and then go ahead and part this guy off to lengths yeah Yahtzee and then we'll flip that guy around and face off the end and I'm gripping this quite lightly because this is a thin-walled hollow tube but for a light facing operation like this we don't need a turbo grip on the chuck alright so there's the body and the cap looking fine and we'll double check make sure that guy assembles nicely and that's looking really good here's a dirty little secret for you I actually made these parts twice because I misread the drawing the first time and made it the wrong length so that's how I happened to have the other footage of cutting the relief area on the end in a different order of operations all right now onto the pointer they're shown in teal and I'm gonna make this out of a single piece of a one tool steel in the US we typically call this drill rod so I cut it to length and I'm gonna go ahead and start with the four jaw because we're gonna need to maintain concentricity here through multiple operations and the nice thing about drill rod is at the outside of it is precision ground so it's quite easy to get it dialed in very precisely now I'm going to face this a bunch of Center in it but if you have a negative Center for your tail stock a better order of operations would be to put the point on now and then use the negative Center to hold that for the rest of the operations but I don't have that so I'll show you the other way to do it to put a center in there traditional style and I dial this guy in again because any time you move the part you've probably lost concentricity and of course putting the tail stock in there influences concentricity as well and then I mark my dimensions on there just to get a sense of where things are and I don't know I always do that right away and it's always pointless because then I immediately start turning and I remove all those marks I don't know why I do that it's just a thing after that first pass we are actually very close because this stock is only a little bit larger than the final diameter that I need so we'll do a finishing pass and I'm actually leaving this one foul our Jan you'll see why here in a moment and I'll also deeper that end while I have the chance so as I said we are a bit large and we need a really precision fit on this pointer and of course it doesn't fit yet so what I'm gonna do is finish this off with Emery paper so we can really dial in the tenths on this fit and of course you'll notice I've got protection on my ways there because you don't want to shower those with grinding grit starting with some 320 grit here and I use this to get it down to dimension and basically just to make it perfect what I'm doing is actually just test fitting with the tube over and over I'm not just assuming that the reaming operation left the inner borås is some perfect dimension and I'm actually just fitting it bespoke if you will to that tube and then once I've got the fit perfect then I go back in with some 800 grit Emery paper and smooth out the grinding marks for a perfect sliding fit so with the major diameter established now I can go ahead and Mark for the smaller diameter at one end and this is going to be the negative Center end used with small taps because we've already put a centre in it so I'm bringing back in my dead centre this time instead of the live Center because I need more space to get in close as you can see here to turn down that diameter and that diameter is needs to be as close to it precisely 250 as I can get because that's the hole that we reamed in the end of the body for the pointers to come out of and again I'm just test fitting that little by little until it is perfect and then I can polish that guy up again with some 800 grit Emery paper and then a quick deeper and that end is done and I'm marking the inner diameter and this is the main pointer area so we'll blue that up and Mark it for length as well and this guy I'm just coming in with a sharp nose tool and plunging in directly you can see I've brought the live centre back in for support there I'm taking light passes here because there's a limit to how much you can plunge straight in with a pointed cutting tool like that pretty soon it turns into a form tool and once again finishing a bit large and using Emery cloth to dial that fit perfectly now we can't test fit this inner diameter however we know from the outer diameter at the other end exactly what size is a perfect fit so I'm making this inner diameter exactly the same as the outer one down to the tenth here's our part so far and you can see how that fine emery paper almost makes me look like I know what I'm doing now we need to part this off but we're working kind of far from the chuck here and this is tool steels tough-going so I'm not going to try to part it off in the lathe instead I pulled it out and I'm parting it off if you will with the hacksaw as I said in my parting video there's no shame in using a hacksaw when the time is right so now I'm going to put this back in the Forge on and flip it around but my usual copper soft jaws are a little too thick and so I can't hold the small diameter so instead I've got a soda can on there to protect the part from the jaws and I'm dialing it back in now we have to grip on the larger diameter which leaves us with a lot of stick out I wasn't sure if this would actually work but it did Plan B was to use a split block like this which allows you to clamp down on the part and then you clamp the larger block in the jaws and that allows you to work on a smaller diameter that's outboard of a larger diameter next we're going to set up our compound to turn the 60-degree point on the end of this 60 degrees is the sort of standard taper that's used on centers for lathe tooling and of course also taps and be mindful of your markings on this remember that Chinese lathes have zero 90 degrees different from American lathes so watch for that and now we start turning our point and if you haven't seen this technique before it's pretty simple you lock down the carriage you use the cross slide to set your depth of cut and you do the actual passes with the compound set at the angle and that that creates the angle on the end of the part there that we want and this is a very very easy way to make tapers the disadvantage to it is that you're limited by the amount of travel that you have on your compound which on small leads like this is not very much I've only got about two and a half or three inches of compound travel but for a small point like this it's the thing you can decide how far to take this down I didn't go all the way to a completely razor-sharp point because I'm not going to be hardening this so I figured if I make a really sharp point it's just gonna break off anyway so then I remove the tool marks once again with some Emery paper and there's our final pointer looking pretty sharp well not that sharp because I left the end a little blood so we'll do a test fit in the normal use direction and that fit is great it looks like we achieved our concentricity and our dimensions that we were hoping for that feels really really good now over on the other end if we will flip it around to use for small taps the news is less good it goes in as it did before but it gets stopped right where the end should be poking through the small bore at the end and so just to make sure there wasn't some grit or a little bit of a burr or something in there I ran the five sixteenths reamer back in there by hand and just to make sure there wasn't some tiny taper or something in the end now we know the major diameter is good and we know the smaller diameter is good because it fits through by itself so that can only mean one thing we have a concentricity problem so I'm gonna compensate by just reducing the diameter of the smaller end here a little bit so I won't have quite as good support from the bore on the end as I'd hoped but this end is short anyway so it doesn't matter that much and we'll give it another go here so I took another couple of tenths off of that guy and now it fits in there pretty well but the stick out is very very short so double-checked my lengths here I've got a half inch there but here's the thing remember the reamer is how we made that shoulder and you can see how the reamer doesn't get all the way to the end because there's a bit of a rounded end on Reimers and there's also that hundred an 18-degree drill point in there so that all cost us a fair bit of length so in the end the negative drill end didn't work out great but the main end is awesome I can't feel any lateral play in that at all so really really happy with this in now we need some Springs so it's over to the toy box to see what I've got and I think something like these guys will work well this is a this spring has a good length but it's not really stiff enough I kind of want two of them so I could put them in back-to-back like that which would be a fun surprise for later me it's like one of those cans of snakes but you know that actually takes your eye out and that's that's gonna work but I want to kind of combine these two Springs so here's a little trick if you have a link that you like but you need this spring to be stiffer you can kind of weave them together like this and make one stiffer spring you lose a little bit of travel doing this but it's an easy way to get around not having the exact right spring you want this spring tension to be pretty high because it has to resist the lateral loads on the tap but not too high that it's jamming the tap in there and threatening to deform your threads or something like that so that feels just about right okay but how do we end up with that concentricity problem on the other end because we made that part all in one setup right well not exactly there was a moment where I switched out to using my dead center for clearance and in principle centers are all the same but in practice especially when you're talking about the 10,000th levels of precision that I'm going for with this fit the different Center could have made a difference so that's one possibility another possibility is that my live Center may actually not be good enough for the levels of precision that I'm trying to achieve with this part so let's actually check the run out on my live Center you see I've actually got about half a thousandth here and that seems like a lot and well it is but let's see why that is by going live center shopping here's the live Center I'm using it's from a little machine shop and it's very hobbyist friendly priced at $25 but there's no accuracy listed for it which should concern you in itself so let's look at a comparable model on MSC and this guy is $67 and this guy does list its precision in millimeters at 0.01 and that's 4/10 so that's pretty comparable to what I'm getting on mine well here's a right 10 live Center and now let's look at its accuracy oh look at that zero run-out measurable oh and it's five hundred and sixty dollars want to spend even more this royal products live Center is $1100 I guess the name means only the Queen can afford it but maybe that number might be in binary in which case it's only thirteen dollars and two cents I'll try sending MSC thirteen dollars and see if they send me that live Center but the point of all this is that you do give what you pay for and so if you're trying to hit tints diameters and maintain perfect concentricity as I'm trying to do here you will start running into limits of budget machine tooling okay let's finish up our part so I'm gonna do a cold bluing here which I like to do on my tools looks nice so the first step is to clean it up with acetone all of these cold bluing chemicals require the part to be absolutely spotlessly clean and I'm using Brownells ox flow blue here which is kind of my favorite and this guy just wipes on with a cotton swab and it's pretty much magic if your surface finish is good on the part and it's clean then it just instantly turns a perfect oxide black it's pretty awesome stuff you and then we'll do the cap as well and you just let that sit for a minute and then wipe off any excess and a nice finishing touch is to rub some light oil on there for extra corrosion protection I found this to be optional if your surface finish is good the black oxide gives you a little bit of extra protection against rust okay let's do some final assembly here so our pointer goes in like so and that fit is still good which is good because nothing's changed and we put our springs in there and our cap goes on the end and that my friends is a spring-loaded tap follower so out with the old in with the new you can see the difference in quality between those two parts that's the difference that several years of experience in machining makes I hope you've enjoyed watching this and I hope you will make your own tap follower check out my patreon for the drawings and I'll see you next time you

Channel: Blondihacks

Views: 177,110

Rating: 4.9272971 out of 5

Keywords: blondihacks, machining, machinist, abom79, this old tony, vintage machinery, steam, electronics, making, maker, hacking, hacker, lathe, mill, woodworking, workshop, shop, model engineering, engineer, engineering, live steam, machine shop, metal lathe, vertical mill, metalworking, metal shop, jewlery making, diy, home improvement, resin casting, how to, do it yourself, do it yourself (hobby), ASMR, mini mill, mini lathe

Id: IQfC0K-U2dU

Length: 23min 55sec (1435 seconds)

Published: Sat Jan 11 2020