Expansion Arbors --- No through hole...No Problem..Take a Look

hey guys drill PI here in advance innovations welcome back to the shop the one true statement that I think that we can all agree on is in a machining environment you can't cut it if you can't hold it and we all know that there's a million different ways to hold any job that you get on any given day well today I'm going to show you something called an expansion Arbor so if you're a tradesman and you do this for a living you know exactly what an expansion Arbor is well over the years I've been faced with a couple of challenges that an expansion Arbor was a perfect candidate to solve as far as workholding is concerned but there was little things that just made it not practical and that's when you evolve and you come up with new and fresh material anyway I've got a bunch of parts sitting on my bench out of the shop and I'm going to show you a couple of different styles of expansion rubbers and a couple of different generations of each style to overcome certain workholding problems so let's take a walk out to the bench I'll run it down for you hope you like what you see alright guys this is the most common type of expansion Arbor this is strictly an aluminum slug the drill then tap this is a 5/16 18 screw 82 degree countersink split six ways in a band saw nothing precision a relief cut so that the Flex is a little bit amplified if you didn't put this relief cut in there these would be very hard to spread out and don't get too crazy with how deep the relief cut goes because when you put your six slices in that wok and get pretty thin and you may lose the whole effect of Flex so you'll get a feel for it air for a while and whatever you do when you use an arbor like this this is going to go down inside of a part and you reach down inside the part with you or allen key and you tighten up on your screw and it expands because the screw forces the feet out alright let me say when you do this make sure that the screw that you use extends beyond your cut it'll be a lot stronger for the arbor okay but this just happens to be the only screw I could find right now so we're going to use this one watch the gap open up as I turn this down see how it flares that's not distortion from the camera that's the part actually opening up it's a tremendous amount of force when this countersink hits that counter you know its underside of the counter screen screw and forces it out now when you're making these the location diameters should be turned in an expanded state so when you put this in your lathe put a little bit of torque on this open it up a little bit and then turn everything to your finish size that way when you're done and you stick your key back in here and you release the pressure it closes down a little bit and it's easier to get your part off not a problem right if we get that in there turn it now for whatever reason you need to hold on the OD of this part or excuse me hold on the idea this part now it's in your collet or your Chuck you can access the entire outside of the part let's change this up a little bit let's say the boss tells you we're gonna make these out of acrylic and you can't use an expanding arbor like this because the pressure is so great that it's going to blow up the acrylic now what do you do well I'll show you how I overcame that feed you some food for thought you can do with this as you please this is a relatively unassuming looking a little arbor here this is a quarter 20 countersink screw this is an 82 degree head on this wherever you are and whatever kind of hardware you use make sure you match the screw to the countersink now this is strictly a determined diameter and I'll tell you why and how to determine the diameter a sleeve and a cap if you have a piece of delicate material and you don't want to crack it but you do want to drive it I'll search around your shop for an o-ring anything close is fine it doesn't have to be spot-on and you can see this o-ring is pretty far from being spot on but when you stretch it over top of a piece of material it's going to get a little bit bigger so keep turning your blank down until when you stretch the o-ring over top of it it just about drags on the inside of your part we're gonna put the collar on just to start somewhere put the cap on put the screw in [Applause] now this is an arbor that I developed many years ago to hold acrylic tube because every time we clamp down with the aluminum expansion once it was blowing the parts so now when you tighten down on the cap watch the o-ring your ink displaces because of the pressure it's a very even pressure and believe it or not it's as strong as it is gentle so you put that on there and you torque down on your screw that particular row ring is going to expand and it's going to drive this part quite solid now the reason there's a sleeve on this if you find that a single o-ring doesn't do it for you and you'll have to forgive my fungal fingers here I'm looking through the camera I'm not looking at the parts and there's a just a tiny little delay so it's kind of hard with the o-ring up [Applause] you'll get yourself another ring yeah [Applause] I'll just squeeze it down they'll both come out I think you'll find that there's more of a front bias than a rear bias here and believe me this is incredibly strong if you were to take a piece of tubing like this that had a real thin wall and stick it on here and squeeze down on this cap you would actually see bubbles in the OD of the material from the strength that this can offer all right so let's go one one step beyond this the boss comes and says okay here's your part I want you to stick this on the expansion Arbor and I want you to work on the backside I want you to do some work on the opposite end of this now it's already been board it's already been undercut it's real delicate it's plastic you can't squeeze it in a three jaw Chuck because you'll smash all these ribs and you say okay no problem we're just gonna take this guy right here loosen it up do exactly the same thing you just did with the other part stick it on there's no hole in it so now what how do you use an expansion I run a part that doesn't have a hole not a problem take the cap off we go to plan B Plan B is a threaded cap we're over the top bring the screw in from the pack ah boss thought he was gonna trick you on this one but guess what not today but you stick that in there and torque down on that cap that cap displaces those o-rings just fine there you go you just used on expansion Arbor on a part that does not have a through-hole so I guess we could call this an expansion plug and although there are no set dimensions for this the one thing that you want to be sure of is whatever screw you use from the front that the tap drill that you use for that screw is larger than the major diameter of the screw you come through from the back lift since I used a quarter 20 from the front and the tap drill for the quarter twenty is a 201 201 is just a little bit bigger than a 1032 so I have a 1032 coming through from the back for the cap and a quarter 20 coming through from the front for the tube so there you go you have an expansion arbor that will hold I D OD [Applause] whatever true hole no through-hole it doesn't matter that's style number one actually that's style number two let's see what that other one looks like let's say though yo rings are slipping and you don't want to use the O rings well you get the same problem with this one you can't get this one on or you can get it on but you can't tighten it you can overcome that problem exactly the same way as the first one but only here's your solution an 82 degree plug goes down in the countersink screw comes through from behind now as you tighten up on that screw there you go it pulls the plug down into the countersink and expands the part stick it on tighten it down and that my friends is not going anywhere that is very strong and will distort your part if you're not careful so when you're using delicate material Plastics thin wall brass copper anything that's going to be influenced be very careful on how much pressure you put on it and you may wish to consider the o-ring style because the o-ring style is a continuous contact and it's very even pressure naturally the more serrations you have to your arbor [Applause] the less distortion you're going to have if you only had four cuts it's going to go off at 90 degrees and you're going to turn your part into a square actually it's going to have high spots and low spots it'll be round while it's turning but when you release the pressure on the arbor you're gonna have an inconsistency in the thickness of your walls there you go guys two different styles of o ring or excuse me two different size of expansion arbors a couple of different thoughts on each one through holes bottom holes it doesn't matter these guys will get you over the hump we'll get the job done look you like what you see thanks for watching they do have one more thought for you when you make a conventional aluminum expanding arbor like this one and you're coming in from the front with your screw [Applause] this is the most common type of expansion arbor you're going to find laying around a shop the majority of the flathead screws you're going to find the threads do not go all the way to the conical feature on the underside of the head so when you make your arbor drilling tap for the flathead screw that you're going to use that take a little bit bigger drill and go about an eighth of an inch from contact and knock the threads out this non threaded section here that's bigger than the screw will allow for the non threaded section of the screw and allow you to drive the screw all the way down comfortably without galling up your threads keep it in mind okay well aside from the conventional split aluminum or steel expansion number I hope you got a couple of good ideas on ways to get around your specific problem naturally whenever I show a technique or present a thought or a process in my shop not only is it to introduce you to that particular process initially but to stimulate your thoughts and say hey you know what I could do with that so take the idea think the concept apply it tweak it twist it modify and however you need to modify it to get your job done and remember where you saw it if you like what's your song you're going to leave me a comment hit the subscribe button on the way out let's try the subscriptions up that would be a great way to say thank you anyway that's all I got I hope you got something out of that that style expansion arbor package has served me well over the years and I will continue to use it and you'll need to apply advance admissions Austin Texas you

Channel: Joe Pieczynski

Views: 103,360

Rating: 4.9770494 out of 5

Keywords: Joe Pie, Joe pieczynski, Advanced Innovations, Advanced Innovations llc, machining videos, lathe videos, shop videos, shop tricks, shop hacks, master tricks, expansion arbors, expansion plugs, machining 101, machining tutorials, machine shop, work holding devices, apprentice, texas machinist, texas machine shops, work holding

Id: J1RFTRzuAcU

Length: 14min 27sec (867 seconds)

Published: Thu Oct 12 2017