Techniques for Machining Straight Deep Holes -- SHOP GEM --

hey guys don't buy here too advanced innovations welcome back to the shop you know a question that I get a lot is how to drill a small diameter deep hole there's a technique for it there's a technique that I have for it that has proven to be fairly successful over the years and when I started thinking about how to convey that particular demonstration it led me to something which led me to something which led me to the board right here right now so I'm going to put something up here that I thought was it was a good tip bit for you to be aware of and to see this it's kind of unbelievable until you until you really crush the numbers and look at the geometry of what's going on its lucky we can drill straight holes at all so let me grab a marker here put this up on the board for it check this out let's say we're using a try to make this round and large enough so that you can see it that's a potato right 250 diameter six millimeter 250 died number there's your drill your drill starts going in that hole resulting in I didn't seriously gonna we're gonna do it anyway so hang in there a 252 hole not unusual right couple pound bigger now if you look at the potential for a round peg in a round hole to bounce around with these two dimensions what do you have to thousands worth of total indicator reading or to thousands worth of movement a thousand either way here's your center know about that rock your world here's a watch that this this is from here to here to 52 52 symmetrical let's assume for a moment that they are coaxial this gap right here is a thousand this gap right here is also a thousand now 250 drill does not have a round footprint on it until you're at least three times the diameter give or take depending on the grind of the drill into the drill that's when you have 90 degree contact until which time you're relying on edge contact which greatly reduces the footprint of the inside unit let's take that to a horrible extreme let's look at the inside tangent point right there and strike the line vertical so right here to the hole one thousandth of an inch gap right there what do you suppose that is I'm failing that almost 16,000 seven-inch both ways so the potential for that drill to dance around a quarter of an inch girl to dance around a 32nd of an inch until you're about three quarters of an inch deep that just blows your mind now if you get it to a smaller diameter drill it gets even worse because now rigidity comes into play and the drill could even be flexing why is this important well this is important for many reasons to be aware of this 1016 'thou potential error depending on mating geometries is especially important in tooling if you have a milling machine and you're trying to make two plates that go together one with pins and one with holes and you're mm soft on the center of thousands off on the center and it won't fit together will you use what's called the diamond pin and this is what the diamond pin does it addresses this problem right here I'll be side step here for just one second and say when you have fixture plates that are going together one has a pins in it one has the holes in it one of those pins actually doing well and then he'd give it time you have the two pins unrelated to the 250 of all just use of the board one pig controls rotation right and the other pin controls the angle so this one here is just dance a hole over the place until it gets in line with this one and then it locks in so that they both have to be round no they do not the pivot point needs to be round the location pit needs to be round the angular control pin does not this is where you would use the diamond pin now I'm going to draw that a little bit out of scale of course but just to give you the idea based on the black graphic the diamond pink would be shaped like this just like a diamond but on the outside edge you still retain some degree of the radius of the original pin and that is right here that is that particular chord of the circle which controls boom perfect now knowing what you've seen here the smaller you make that diamond here the more leeway you're going to have Center to Center so if you have an old rattle out machine that can hold its own no matter what day of the week it is and you try to make a precision fixture there's your answer the diamond and the diamond works because of what you just saw right there get that off of there draw something different on the inside let's make that a square because basically that's what you have when you're looking at four points of contact if you have a square I'm going to leave that there because it's very relative to what's going on here this is where we hit the finish word right it comes to square okay four points of contact square inside of circle as you can see as the square starts to deteriorate on one of the two possible pairs of corners this is where this comes into hand this is where it comes into play now does it go all the way around but as these tips go away or as they're removed for cooling purposes you can see that it doesn't matter how far they going after a certain point it's the sites that work and not the top so this is really handy to know for cooling purposes and if you've ever tried to do that on an old worn out machine two pins two holes doesn't always work I know you guys are already piped will slot one of the holes stop tightening you can do that too you can make a slot on one side you can make a round hole on the other does exactly the same thing as a round hole or a round pin and a diamond pin but it may not give you the reverse ability depending on the design of whatever it is your design so as far as the rather time you are concerned that's what's happening now let's look at this from the drill aspect five more an answer let's put at the top water for it you have a small primary edge on the drill or the diameter of the drill you are cutting edge after all the total blank here here we go like that a little bit of heal relief here's your drill as it's cutting it should be cutting fine but it still has that 15 thousands worth of movement potential as it makes contact keep that in mind happy you Ted let's move on to the good stuff so you get a little bit of geometry lesson today you get a little bit of milling philosophy and you're going to get my philosophy for drilling long skinny holes with the great deal of success one thing that I've seen and I got to laugh when I see it because it's an innocent mistake it's not stupid or right here it's just innocent you don't know you don't know if you need to drill a hole that's let's say four inches deep if you can drill in half and half from side to side and do that that way it's only a two inch deep hole but don't start with the four inch drill just don't do it because as you apply the pressure the drill is got an opportunity to bow from the pressure you may be able to visually see it or not but as it bows the tip geometry aims in a different direction and before you know it that drills doing this down inside that hole and there's no way the two holes are going to meet they're just not I've actually seen guys drill holes where the drill actually blows out the side of the part inside the Charter inside the collar they pull it out they go hey how come I can't see through the hole that's because it came out the side drills are a lot more flexible than you think and they will Bend they will flex they will walk so the most important part of drilling a deep hole is the beginning you absolutely must pay attention to the very start of that hole if it's a matter of super precision that you need don't trust the center drill type of small center drill in there and then bore it you got to make sure that that initial footprint is running concentric or the rest of the hole it's just a crapshoot it really is so here's the fun ladies part we're gonna put Chuck over here color over here whatever we're going to put the part right here here's your part sticking out first and foremost if you've tried to drill a deep straight hole in a shaft or god knows what make sure that the part that you're working on don't assume anything check the part a lot of times you'll get a piece of material from a bar end that may have a little bit of kick to it before it straightens out we roll it on a surface plate look for it to do the old flip-flop thing as it's going to look for a light under and in the center as its rolling make sure the part is straight that's really important because if you're going to grip it end to end and it's been pulse they may meet but it's going to be an apex and it's not going to be a straight hole all right step number one Center to a level spot drill at center drill it I don't care what you do just start the hole I personally use center drill pretty much on everything these spot goes on the mill you center drill dolly put them all in here that is close to the size of the hole that you want don't go don't go full guns and say I'm just going to get knocked this right out of the park don't do it use a stub drill important used to sure this drill that you can get away with initially to drill a deep hole you don't use one drill you use several drills as you get deeper into the hole you change the drill put a little bit longer drill in there and use the amount of flute that you have on that and then put a longer one in use the amount of food that you have on that and then go for the throat with the deep one don't start with the deep one first have several make sure they're sharp in the beginning put that undersized haul in here if you have to board it at this point if you need a really small boring bar to make sure that that drill didn't do that high point low point thing that I just showed you before dust that hole until your gauge pin fits in it now it may be eccentric maybe it's not eccentric but put a lead in here make sure that that is running true you only will need to make sure it's encrypted to true olace before I don't care how many guys are going to scream it out I can do it with a reamer you're never going to get the same concentricity accuracy that you will with the boring part it's just you won't because drills and Reimers are slaves to the pilot if it's a wall or down hole and it's going eccentric when you stick a reamer in there it's not going to true it up it's gonna follow that ugly hole it's going to open it up but it's not going to true it up the only way to do that is with a boring bar okay so for a small lead in there then take your reamer the size of the finished hole and read that hole read the first half inch or 3/4 of an inch depending on what diameter of X you're using ream it out so we have a center drill a pilot hole a bore a dust board doesn't have to be full depth quarter inch whatever just something that's running true and when that reamer hits it the remark is going to follow the true concentric feature formed by the boring bar and it's going to walk in there and it's going to clean this up and it's going to give you the square contact points that you need for your twist drill to locate at the tip and somewhere in the back at ninety degrees that's what you're looking for how far into that drill can you get so that the tip of the flutes at the nose of the drill are 90 degrees to the next contact point look at that distance on your drill and I think that you'll be shocked at how far apart some of those are once you have this concentric relationship that start with a smaller drill progressing up through the longer and finally to the ultimate left no push up be patient use lubricant and make sure that you retract the drill to clean the flutes out often if one flute packs up that's the flute that says I'm not going any further and the other flute tries to do the work you'll take some hard left you think you had it all going on but it got hot it got a cold fusion and just ruin the part good way to do it speaker walk out I'll pop one in I'll probably go fast forward on it because it's a it's a process that you just need to take your time but the fact that you have a pilot board pilot and then a Rheem guide and then go with the drill doesn't hurt so it's way I do it that's what I've always done it and it has worked outstanding every time keep the reamer handy about every half inch inch or so depending on what you're doing put the reamer in there and if you want to check whether or not the holes walking out back to everything off clean out the hole stick a pin in it and let the machine run on a slow rpm if the pins doing this well you might as well go get yourself another piece of stock because it didn't work hey let's do it let's take a look at the parts we're gonna use for the sample this is a three quarter inch diameter slug of 316 stainless or inches long just over four inches long I will face both ends of this because I'm going to drill this from both sides I will see how deep I can get it from one side but let's just start with the fact that we're gonna try to do it from both sides face it off center drill it both ends we're gonna go for a 201 through here that's a number seven drill 2:01 I'm gonna take a 191 diameter drill I'm gonna go about 3/4 of an inch with a 191 diameter drill I'm going to follow that up by boring it to 201 finish sighs guys 201 only have to go man 300,000 have to go very deep but make sure this is a very nice fit on the gauge pins make sure you have several gauge pins laying around you want this to be right on size with the pin any slop here could affect the whole rest of the show take the reamer finish the reamer to the depth of the pilot hole you now have a built-in drill guide for the remainder of your drill or drilling operation we're gonna use three different drills for this for about the first inch give or take I'm going to use a stub drill high speed then I'm gonna go to a jobber length and then I'm gonna go to an extended do not start with the long one work your way up just like you're working your way into the part work your way up in sizes of the drills these are not that expensive if you have something that's critical there are only a few dollars a piece go online find about one of the local supply houses and get them before you start the job you will be glad you did now inside I talked about high-rise drills or high spiral or fast spiral drills and this is a perfect example of that let's line up the flutes you can see the one on the right is considerably slower and by that I mean by the time it comes back around this one has already come back around in half the distance so by the time this one comes around twice this one has come around four times one two three times so this is much more likely to hold a true diameter in my opinion if there's some reason that somebody out there knows the reason that that shouldn't be true by all means put it in the comment line but as per the graphic on the board you can see that by the time this one reaches its ninety degree contact point and has four points of contact inside the hole the distance is a lot shorter then your standard twist drill which goes little bit further back about 50% further back it's a flat bottom all right let's throw this guy in the machine face the end off chances are there's going to be some voiceover because this is not a fast process take your time doing this and as I will show you instead of cranking the tail stock in and out 9,000 times set your carriage as a stop and bump the tail stock up against it make sure that underneath the tail stock is clean and there's some oil on to ways and it should just float right along let's do it okay first things first you are going to hear me say bump the carriage this is what I'm talking about tail stock physically encounters the carriage don't slam it against it lock it off drill back off a half a turn on the crank back this out to clear the drill put the drill back in the hole block it you know at half a turn it's going to engage drill whatever you have to drill back off half a turn slide in and out this is really helpful when it's an exceptionally deep hole if you're in there for inches or so and you have a hundred-thousand retraction per rotation of your crank you don't want to crank it 40 times to get the drill in and out every time you Peck this is much easier when you run out of stroke rezero your tail stock move the entire assembly in until it bumps to the bottom of the hole half a turn up lock it start the drill out lather rinse and repeat it's a good technique it'll save you a lot of time okay make sure the OD of the part is running true if there's any kind of projection make sure you check it two places very first thing we're going to do is pop a center drill in there and I'm real happy that the one side of the center drill was severely worn and the other is not watch it start the vibrate just a little bit it's chattered just a little bit and I'll tell you from where I was standing it looked like it was running out a mile when you know you have a deep hole it's absolutely critical that you start tight start tighten and right so let's spin the center drill around I've shortened up on the spindle projection I've locked it I'm dragging the lock right now and I'm feeding it incredibly slow so the center drill is now acting like a boring bar it's cutting the run-out off and it's cutting off the chatter on the bottom of the hole and believe me when you encounter this you'll feel it you'll hear it there'll be all kinds of indications that it has happened I'm gonna take it to just about finish sighs not going to go full 250 it's only a tool one hope next thing we're gonna do is put the 191 in there that's a 10 thousands below or a quarter of a millimeter below the final size hole got to go about three quarters of an inch deep or or 20 millimeters give or take and when you see stainless steel kicking off to chips like that coming out of a high-speed drill you know it's cutting very well this is running at about 425 rpm possibly 320 at this point and I know a lot of your screw machine automatic CNC guys are probably saying wow that's way too slow but when the drill is cutting good leave it where it is don't mess with it and we're getting a little bit of smoke the wd-40 that I'm using as a lubricant does work believe it or not a lot of people say it doesn't but the wd-40 does work and if you have the smoke then that means you have friction and it's not optimized it's cutting good so I'm not going to change anything and I run this down to the final depth to clean it out we're going to put a boring bar right here we're going to come back and we're going to bore the 201 diameter to about quarter of an inch deep make sure you proper sized boarding bore everything clears and bear in mind we only need to take five thousand assault so just a small dust cut initially I'm going to go about as far as the relief section of the boring bar there's really no need to go any farther I'll boil the chips off and I have several gauges handy 199 through 202 and I always start with a couple thousand X cut that I can dial in I can dial in at least as much as the difference between the pin that I selected and the finished size of the hole that gives me some place to start I believe that was a probably a 197 reading and I'm feeding that by hand going a couple times in and out you don't want to spring past to get a come up and bite you in the butt at this point and start checking it with the pins that are within the range for the size you're looking for shooting for 201 and on this side I'm going to be honest with you guys I was a little bit over the 201 the - OH - just about stuck in there and I figured why not it's close enough that I was gonna fake my way through it I'll be the two hun 2:01 and the 202 you can see right there by my index finger but a 1/8 rock-solid so I'm not going to mess with it this is where you pull out the reamer that pilot diameter that you just bored in there is now the guide for the reamer so the reamer is going to track true regardless of what that 191 hole is doing that front board pilot is going to keep this reamer tracking straight don't get over-aggressive with it don't drive it in like you're trying to split wood or anything just drive it in nice and easy and I want to say thank you to stanza Kowski for giving me this anchor loop I've been using it for tapping stainless and found out that it's quite an amazing fluid I believe all industrial supplied it for the Bosch and I got a couple samples while I was out there so thanks a lot Stan I'm a big fan of Molly D and this isn't nearly as nasty as Molly D but it does hang on to the cutting tools very well so I highly recommend this anchor loop stuff I'm new to the applications for it so if you've got something that you use it for by all means put it in the comment line all right first on size drill number 7 201 diameter this is a high speed steel split point 118 degree stubby 320 rpm I know that sounds slow but when this drill hits that 316 stainless you're going to know right away whether or not it's cutting and Italian the way this thing was puking those chips out of that hole I just couldn't ask for a better the rapid retract is the whole tail stock moving I am not dialing back on that be careful that you do not run out of flute relief on your drill because the chips will pack up and you're going to get yourself in trouble I am marginally at the end of the flute relief on this drill so it's about time to switch over to a new drill very good possibility that I am going to refloat that reamer down in that hole just to get a good feel for whether or not the hole is still tracking straight when you put that reamer in there if there is an eccentricity between the drill and the reamer you're going to feel it when you crank it in it's going to give you a little tapping feel you're going to feel it as it's going in if it's still running concentric it's going to float straight in and you're not even going to know where you're at you're just going to hit the bottom of the hole and come right back out switch it over to the job relents drill here this one's got about two inches of flute give or take and as luck would have it I ended up not using the extended I did go in from end to end and we're going to show you the pump the carriage setup right now right now I just pulled a carriage back so that I can slide the tailstock up and bump it going in with the the jabra length drill until I hit the bottom of the hole I will back off about a half a turn and move the entire tailstock out this one was cutting so smooth I just didn't have the heart to change anything up so I just kept it going chips are flowing keep it going and if you don't have a long string coming off the other side of your drill at least check the flute and make sure that there are chips in the flute you do not want the drill cutting only on one side that is a recipe for it to kick and it's going to walk off and you're going to get a hole that's down inside that part whipping around and you just can't see it I think this stuff this anchor loop is pretty good on stainless this is not an infomercial for make your loop but I was really impressed and these tools were ice cold quite shocked that they were still cold normally when you push in a high speed steel tool down through stainless steel you're going to generate some heat but I was very impressed and that doesn't happen very often all right I'm about full length on the flute length of this particular high speed drill the Jabra drill which is your standard kit drill when I think I'm about halfway or I've run out of flute relief on that I'll put the reamer back in and I will float the reamer down to assure that we have fairly continuous diameter and everything is nice and straight you may have to just several times to realize that the tailstock is actually moving out as I'm setting it I'm pushing the tailstock back when the drill hits the bottom of the hole back in with the reamer same speed 320 rpm nice and easy you can see that the tailstock quill is a little bit snug it's not locked down but the with the black vertical handle there's a little bit of drag on that alright we're about two hundred quarter inches deep 201 diameter 316 stainless steel we're going to flip this part over we're gonna do exactly the same thing on the other side possibly add a little faster frame rate as not to bore you to tears hang on [Music] [Music] all right guys we're gonna change the camera angle here and see if you can follow along I am bumping the carriage with the tailstock unlocked I'm going to move the drill till it just hits the bottom of the hole and watch the tailstock walk back a little bit now I'm going to lock it and as I drill and we'll pull that whole tail stock out read bump the carriage unlock relock it you'll notice that I always back off about 1/2 to 1/4 turn and that is so much quicker than cranking it all the way out night and day difference once you've done that you'll be really shocked at how much more you're going to enjoy that and like I said before that drill is ice-cold I just did that because of that anchor Lou I didn't want it on my fingers I'm gonna pull the tail stock all the way in the tail stock is not locked I'm gonna run the drill to the bottom of the hole and watch for the tail stock to push back okay now I'm locked I'm gonna bring the carriage up - that's not my stop point so every time I bump into the carriage I know the drill is shy from the bottom of the hole if you jam a drill down inside of a spinning part like that it's going to bite and it's going to blow up and you can kiss your part goodbye I did use two speed ranges to drill this whole first side was thought at 3:20 all the center drilling all the reaming all the pilot drilling boring everything was 3:20 the second side I did at 425 and I got to tell you that at the the feel of pushing those drills down in that hole was much better at the 3:20 than it was at the 425 there you go there's the speed change right there as I said previously this is not an operation that you want to rush this raw footage was about 40 minutes I guess it was and that's not all it's worth of runtime that's a camera angles and such but forty minutes total edited down to what you're actually watching now doing the same thing with the reamer floating the reamer in after the drill joints match you'll feel the bump if it's out of whack you're gonna know it because it's gonna you're gonna feel a little clicking feeling going on in that handle it's gonna feel like you're it's just gonna feel like someone's tapping on that reamer pull back probably move the carriage up if I had to guess nope tailstock is unlocked we're going to hit the bottom of the hole watch for the canary go let's move back and we start the drill set the carriage stop here we go this is accelerated footage and I do apologize you guys would be bored out of your mind if you had to watch this whole thing I know it was tedious just to film it but make sure you got enough lubrication underneath your tail stock so it floats on the oil if you have to lift the nose in the tail stock up and write it up over the oil that you've put on just make sure there's no chips or anything on the ways as you do that get a nice thick machine of oil underneath of that tail stock and the thing will literally float back and forth quite well now you got to be patient when you start getting the drill in as deep as it is now it's not solid two inches into this part make sure you have a the chips are coming out same thing with the other the chips are only coming out on one flute check the drill or replace the drill because it's only going to bite you in the end make sure that you proceed gently towards the breakpoint because when this drill breaks through it's going to want to grab just as if you were drilling a piece of sheet metal so keep everything snugged up take small bites and genuinely have a pretty good feel for where you are as you proceed deeper into the hole make sure you don't run out of flute with your drill make sure all your chips can be evacuated comfortably and I think we're about ready to break through you can also see the width of the swarf that comes out of there will get thinner as you're breaking through that's another good indicator that the tip of the drill is breaking through and the body is up not ready to go there you go we're done that's the moment of truth when those holes break through if one hole doesn't line up with the other one you're going to start cutting on an eccentric on the other side the other lead side and it's just going to ruin your day when you feel that bumping going on in the handle and to finish it off float the river back through it you don't have to go all the way through the part go to the parting line maybe a little bit further and just pull it back out let's take this part out collet flush it out some alcohol taken over the bench we'll see if we can get a light down inside that hole and check it out some gauge prints see how we did okay we got four and a half inches of 316 stainless here [Applause] as with any drilled hole it's not ream quality the lead is ream let's see what we got 199 diameter pin yep all day long well within spec 200 201 202 203 it is 201 now this one should go let's give it a little help [Applause] that's that putting about oh maybe two pounds of pressure on that 201 I'm not pushing it very hard but I am feeling the center you can feel where the holes meet but still you got to believe a hardened 201 diameter pin the hole has to be tracking straight and at least two inch increments in order to get that through you're not going to bend that pin - OH - a little bit right at the very tip and I can tell you that that's the first bore pass that I did on the first side so 202 goes in there and just sits in there ever so gently this side no bueno not happening there you go I want to do it do it the way I showed you and try it that was real time I didn't take well I can't say I didn't take anything out I may have I didn't edit this yet but I certainly didn't run that whole thing in real time because you'd sit there and your eyes would bleed waiting for it to happen but don't forget about the unlocking the entire tailstock pull the tail stock out bore the lead for the reamer ream the hole and then start the drill and don't be afraid to remit as you go you will have great success 201 4 and 200,000 a quarter inches worth of 316 stainless not the most friendly stuff for smaller drills that's a win thanks for watching sorry it took so long to get to but it is a time-consuming process take your time make sure you have several drills around be patient lubrication and that whole carriage the tailstock bump thing will save you from wearing out your arm if it's a deep hole it's just so much easier to unlock the tailstock and just push it back in and just turn it unlock it still a good workout but you're not going to wear the machine out you're not going to wear your wrist out doing something I've been doing for a while you want to put something soft in between the two so they don't hammer into each other that's fine when you run out of stroke on the tailstock zero it out move the carriage up until the drills just about there lock the carriage off lather rinse and repeat hope you enjoyed what you saw I hope the whole diamond concept for fix tree and the multiple tools for a straight small hole help you in your shop and I thank you for watching joepie dance innovations in austin texas stay well be safe see you you

Channel: Joe Pieczynski

Views: 72,511

Rating: 4.9308801 out of 5

Keywords: Joe Pie, JoePieczynski, Advanced Innovations, advanced innovations llc, how to, machine shop, shop tricks, shop hacks, shop techniques, shop tutorials, drilling deep holes, drilling on a lathe, how to drill deep holes, lathe work, running a lathe, lathe tips, lathe hacks, drills walk, stopping drills from walking, diresta, furze, ave, ave e, abom, abom79

Id: jnwVCliIiPI

Length: 44min 57sec (2697 seconds)

Published: Thu May 28 2020