TIPS #201 mrpete Centering a Rotary Table on the Bridgeport Pt 1

howdy again it's mr. Pete and in this video I'm at the Bridgeport mill and I'm going to show you how to set up and center your rotary table properly and accurately so that you can use it with the degree of confidence and accuracy and make make good parts but in the next videos already completed but not shown yet on numbers 203 and 204 I make this crank adapter on the rotary table but in order to make this you need to Center the rotary table as I'm going to show you and this and the next video this video will be will deal with this little rotary table the six-inch ER and in the next one I'll show you how to Center my Palmgren rotary table so stand by for that not only will I show you how to Center this with the spindle of the bridge board but I'm also going to show you how to Center your three jaw Chuck or four jaw Chuck whatever you happen to use on top of your your rotary table or you may use nothing but I'll show you this too and I'm going to show you this by a quick and semi accurate method as well as the more accurate method using dial indicators on my particular Bridgeport the scale for the accurate the Dro is right on the front here and this interferes with the wheel on this rotary table now that may or may not be true with yours or your scale may be mounted on the back of the table but notice that the wheel itself is riding right here and we got a space underneath here which is no good so some time ago I made this aluminum plate and this is accurate the machining plate that's a half-inch stick but I mount my table on top of this and then I Center in a manner such as this now make sure you wipe everything off you can't have any chips or debris underneath there but these slots pretty well aligned with these slots and I'll use my mighty bolts and bolt this down but actually I'm just going to Snug it down for now but notice now I've got plenty of clearance under here to turn my crank without any kind of interference so that's the purpose of the plate you may or may not need one of those and this is a relatively small plate it's only six inches in diameter now why am i going to all this bother well if you do not have a reference here where the center of the spindle or the quill lines up with the center of the bore of the table here you just have no reference at all in regards to the dimensions you're going to machine so it's necessary to do this probably in almost all cases when you're using a rotary table I suppose there's exceptions but I always do this now notice that I've got the bolts in place here but and they're just snug but I have plenty of wiggle room yet where this can move around and I'm not going to tighten that yet now the hole in here and this particular one is a number two Morse taper and I notice that from looking through the catalogs that many rotary tables are made with a Morse taper in here but not all so double check to see what yours is but this is a Morse taper and here is a Morse taper shank that I'm sticking in there just to show you and prove it to you what it is but I took a brand new shank that I bought our Arbor it's a number two here and I did sawed off the tang because it was just interfering was in the way so I saw that off and put a little bit of a chamfer on there and on this particular end here this is exactly 3/4 of an inch in diameter now most of your Jacob's arbors are going to have a Jacob's taper here but you can buy the in many different styles but if you're going to use this method get one with a straight shank right here what I'm going to show you here is a cheap and easy way without indicators of doing your alignment using again this Arbor here 3/4 number 2 Morse taper and here is a 3/4 our eighth a collet which I'm going to put in the spindle here momentarily and all I'm going to do and make sure everything's clean when you do this no chips in there wipe this off and I'm going to put that tap it down in there and then I'm going to put the collet in the spindle and basically using the X and the y cranks move this into position so it lines up perfectly with the collet so let me get that started but I still want to make sure there's just a little bit of wiggle room here before I tighten this down I made this extra thick washer here for a reason and I'm going to put that on there and I may or may not need it but the whole idea here is if I can't get this to pop back up out of the tapered hole I can use wedges under here to pop it out without taking everything apart and tapping this from the other end that is the bottom of the of the rotary table so again wiping that off with that washer on there tap it down and I've already got the 3/4 collet in there and I'm going to move the table around now until I get my alignment now I'm showing you just a slightly alternate method of doing this and this might be preferable but I have the shank mounted in the collet now and again I got a little wiggle room here and I'm going to put the washer on there just in case I need it and bring this down into I slept it down into the table now the table now without putting too much pressure on I'm going to back off the pressure on the quill just a little bit and you can see that I'm able to move this around and by doing that I'm hoping that it floats wiggling around like this floats into alignment now I will snug the nuts up just a little bit equally both sides so you do not influence it or move it you can we're talking about thousands of an inch here now snug them up until I got them tight enough for working now I may be able to pop this Arbor out I'm done with it now by forcing up on the quill right here but I don't want to damage anything and I did pop it out but it won't always pop out let me show you the alternate way I probably waste a lot of time your time in mind by showing you different methods alternate methods but again at this point the arbors pretty tight in into the table but using the washer and a couple of brass wedges I can easily get it out of there and now we'll set this aside we're basically done with it for now and I'm going to confirm with the dial indicator now to see how accurately I have positioned it but before I do that I got it in position now I'm going to turn the digital readout on and I've zeroed it out and presumably we're aligned at least semi accurately and probably plenty accurate for a lot of work that you might do with a rotary table I have mounted my starett last word indicator directly and a 3/16 collet and there's a ball joint there so this can be adjusted around and of course you can use any kind of indicator you own or whatever your little heart desires but in this case I'm using the last word one of my favorite indicators and as I lower the quill I've already pre adjusted this into the hole and it's coming up to zero now remember that the hole is tapered so and I'm proving it right now by going up and down and showing you that it's it's tapered but I'm going to put it right on the zero now and I'm going to rotate the spindle not under power do not turn the machine on I'm not turning the machine on at all until I get with the coaxial indicator at which time I will roll up my sleeves but let's see how accurate it is I'll spin it around 180 degrees but I need to get my mirror there to look at it that's the inconvenience of using this type of indicator but naturally you can't see it I would have to stick my head back here but let me grab my inspection mirror okay I've got my inspection mirror from the dollar store and I turned it back to zero here now it may look a little bit off of zero because of parallax error but watch the mirror now as I rotate it around 180 degrees and I'm within going to get a little closer within a half a thousand to our thousandth or so so it's right on and this is in the y-axis so let me reposition the camera and do it in the x-axis so that that way is good but that does not necessarily mean it'll be perfect in the other axis now let's have a look see in the x-axis and we're right on zero there and I have not changed the face on that so it has remained the same I'll turn that 180 degrees and you can see this an inconvenient using this type of indicator and it's pretty much it's about a half a thousandth or one thousandth off that way so you can see that this method here is really quite accurate or reasonably accurate however not perfect now since I've got the indicator on there at the moment now I could correct it very easily and get it right on fact that's what I will do here in the next clip the Dro is still in the zero position from the previous experiment here using the shank so I'm going to purposely take it out oh I want maybe seven thousand sideway in and then you know about six-and-a-half thousands there and now I'll use the indicator to bring it back in but I'm not going to look at the Dro of course that that is meaningless right now until I use the indicator and bring it back in although there's a reference right now because I know where the zero is I could dial it back in but that would defeat the purpose of this demonstration so back down here to the indicator just so it isn't too easy on myself and I'm moving the dial a little bit so I don't have the reference that I had a minute ago I don't know where the zero is now but before you use an indicator try to align the spindle as close as you can with the center of the bore on the table the rotary table and you can do that by sticking a Oh an end mill in there or just a piece of a half inch shank or whatever so that you can eyeball it that you're about in the center of the hole these indicators only have a range of about thirty thousand so if you're way way off to one side you're going to struggle with it so I'll bring it down into the hole and then I like to zero it out there are different ways of doing this but it's if you haven't done it before it's a little confusing and then again I'm working only in the y-axis now forget about the other direction and I'll swing it around now you're not going to be able to see that but I am a full well above five thousand so off so now I'm going to zero out the digital readout and I'm looking at that now and I'm going to move it five thousandths are actually half of that amount and swing it around and you can see now I'm about four thousand adjust a little bit I got just a little bit more to go remember you're splitting the difference and there we are we're on zero and I'm on zero back here okay so I'm good in the y-axis I'll move the camera now let's indicate it here in the x-axis I've got my hand in there to hold the focus otherwise the automatic focus goes a while but take an initial reading here we're on five thousands on this side and when I spin it on the other side which you can't see but I'm moving my head over here it's five thousands on the other side of zero so we've got a total of about ten thousands then that were off so I'm just going to dial this in until it's on the zero and and take another reading at some zero on this side and I'll spin it around and I've got my hand up on the motor and that's how I'm spinning it do not turn the machine on and there I brought it around on the other side I'm looking at it and it's on zero there so that was an easy one and then I would of course push the zero reset the digital readout and I'm right on and then I could lock the spindle in both directions if I wanted to hold it there or I would zero out that digital readout and then just keep the digital readout zeroes in memory until I complete the job whatever it is and sometimes I'll even even leave the Dro on overnight so that's how to do it with a simple indicator like this last word indicator in the next video where I use the Palmgren rotary table I will use the coaxial indicator which is right here rather than the little last word indicator so this is a lot easier to use but they cost about a hundred dollars but I will demonstrate that and I have used that in a previous video as well but it's really so much easier to use because you don't need this pesky mirror so look for that in the next video but now let me show you yet one more step here on this little rotary table when you use a rotary table or many different ways of holding your work and quite often it's going to be bolted directly to the table using tea bowls and in these slots here but a lot of the work that I do is held in three-jaw chucks and here's a little Chuck that you might have seen in some of my other videos but I have a number two Morse taper on there and that can just be driven in there and this is for late work there's no way to fasten this in here permanently other than the self holding number two more staple for but for late work within the capacity of this little chuck it works just fine but again this will only hold up to about inch or inch and a half work so I either use this and that's self centering so I don't need to do any more with it but if I use my other chuck this one here I have to Center it also or all US for naught and I'm going to show you how to do that now and this is nothing more than a four inch three jaw Chuck it's a little buck Chuck that I borrowed off of another lathe and it is mounted again on a piece of six inch machined aluminum here tooling Romanum is what it is and there are two holes that I'll use with bolts to hold hold us down into T nuts but I need to Center this also and I'm going to do that just by a simple method of a holding of a piece of one inch or half inch stock and here it doesn't matter what size it is but remember that three-jaw chucks are quite often inaccurate this is a buck so it's a pretty good Chuck but how far out around it is how far how much run out I don't know but again it's going to be close enough for most of what I do so here's how I Center this Chuck on the rotary table this is a 5/8 diameter dowel pin of three inches long two and a half inches doesn't matter and this could be any diameter but don't use a real small when I would use anything from half inch on up and I put a 5 H collet into the spindle already and I will tighten this down with a goodly amount hanging out I'm just going to Snug this up good in the collet doesn't need to be real tight now I'll take my chuck and you can make make up one of these using one of your lathe chucks depending of course on the size of your rotary table this is really a small table now make sure that the bottom of this is clean no burrs table is clean now we can lay that on there just like this and what I like to do but before I tighten this down onto the jaws I need to get my T bolts or my T nuts rather and my bolts these are 3/8 bolts I'm going to get those started this is a little bit awkward to do so I'm going to do that off-camera and be back in 30 seconds when I made this plate I decided to just use two bolts and it's tight enough for small work but you may need four bolts on a larger chuck but with two bolts and they're just loose yet they're finger tight barely finger tight I have again that wiggle room see a lot more in this direction than what I do over here but nevertheless when I constructed this I did sinner the the Chuck on the center of the six inch aluminum plate so that when I'm even right around here I'm approximately in the location that I want to be so now I'll bring that that down like that and I'm going to Snug this up snug the chuck up that's all the tighter it needs to be and you see it's held pretty well in the center now I'm still able to rotate it but I'm not able to go in all direction I'm just able to rotate it a little bit and now these will be tightened up and always snug them up like you would head bolts snug it on one side snug it on the other back and forth so you're getting it even that being done this is pretty well centered now it doesn't do any good to put an indicator on there because we don't really know how accurate this little Chuck is because I I have used it on my lathe but I don't remember because I got so many different lays in so many different chucks but basically what I've done here now is to Center the Chuck on the table which is already centered and it's all on zero and that's in memory so I'm ready to start the project whatever it may be and in this case in the next videos I'm using it with this setup to make this adapter so be sure and watch those videos too so that's it for this little 6 inch rotary table and stay tuned then for the next video where I'm going to do similar operation with ethyl Palmgren actually it's a larger 8-inch Palmgren rotary table and I'm going to use the coaxial indicator on that which actually is easier to use and kind of fun so I'll see you on the next video and this is a tubal-cain saying so long for now

Channel: mrpete222

Views: 152,010

Rating: 4.9256148 out of 5

Keywords: south bend lathe, colchester, logan lathe, atlas lathe

Id: 4Sujh2WUA1k

Length: 22min 43sec (1363 seconds)

Published: Fri Aug 14 2015