Machining Dividing Head Index Plates: Drilling Hole Patterns

hello Keith rocker here bench machine org want to do a little follow-up video on the dividing head plate so we did a video weeks ago where we showed making the actual disc and then going and getting the I was going to send them off and have a buddy of mine actually drilled the hole patterns in here on a CNC milling machine and anyway one do a follow up video and kind of bring you up to speed where we're at and what we've got to do next to finish these out so I sent my blanks over to Mike Wiggins some of you guys may know Mike he also has a YouTube channel the backyard machine shop where he put some stuff up but mike is a machinist a shop foreman at a commercial machine shop and they run a lot of CNC stuff over there and anyway he offered when I asked him about it to program the these in and just go drill them out on a CNC mill now I got a lot of comments from you guys saying hey I'd really like to have seen you do it manually and I have actually I've said this for I've done these before manually using rotary table and it's quite time-consuming there's a lot goes on there and just to kind of you know tell you the advantages of CNC might got this program he did the number one and number three plates first he's going to do the other four in fact he's already got some of those done but anyway I've already got these two back from him in fact I was over near Savannah Georgia where he works out over the weekend stopped in and actually got to visit with him for a little while and see these up being or not seeing being run but got them from him after he had already ran these two but to give you an idea of the time involved once he got it programming on the mill of the plate number three the one that has the fewest number of holes in it said it took about seven minutes to drill out all the holes and the number one plate which has quite a few more holes in it than the first on the number three plate said it took about 20 minutes to drill that one out so it's extremely fast and basically what he did and Mike actually is going to post a video up on his website talking about this job as well as showing the CNC equipment run I put a link to that for you guys to go take a look at but basically with the C and C it just he goes went in there on his own advice and actually milled out a circle first on some soft jaws clamped the disc down the dis down and then it just basically just drove itself to every one of these holes and just drill them and of course being on the CNC mill it goes real quick and it's very easy to dial in those numbers so anyway let's zoom you in here I'm going to show you what we got and we got a little problem my fault not his and we're going to talk about how we're going to go about fixing that so this is a number to play this is the one that I had and what we were kind of copying to make the number one and three here and as well as the other more specialty plates that I'll be getting later on so when I was doing all my measuring on these things and getting the everything drawn up and laid out or what-have-you I made a mistake and I'm not exactly 100% sure how I did it but I did it and that was when I measured the diameter of this whole pattern I missed it by a little bit so I told Mike that this these these three holes were on a two and a half inch diameter and in reality it's an inch and three-eighths so I was off just a little bit on that and but when I got the plates back I went and was putting it on my dividing head over here and split them around realized they didn't line up and then when I lay them on top of one another you can see that they're just there they're not lined up and so what I want to do is first off it's not a huge deal you know we haven't lost all the work all I've got to do is is drill three new holes in here on the proper hole pattern or on the proper diameter that really does not matter where these mounting holes are in relation to the index holes so we'll just go ahead and here and drill three more holes on the right I am her and you guys will get to see me do it manually so we can actually talk about how we would drill out these hole patterns we were doing a manually of course they only be three holes versus you know anywhere from I think let's see the this plate goes from 15 to 20 holes this plate goes from 37 to 49 holes some of the plates that Mike is doing me have over a hundred holes in the circle around there so you know a lot more divisions involved but anyway you can see it but before I do that I do want to talk about properly measuring a hole pattern like this and quite honestly when I did it I took some shortcuts and I didn't check behind myself which I should have and it's totally my fault but I went back and actually measured these as I really should have to begin with and I want to share with you guys how to do that because I think it's important that sometimes you may run into a similar situation and need to know how to do this you know how do you measure the the circle on a three hole pattern like this you can get some measurements but you know you really need to have a hole right directly across from it to measure a diameter and there is nothing right across from it so I'm going to go through the process of how to do that alright so what I'm going to do is I've got some gauge pins here that are five sixteenths in diameter and that's the same size of the hole and this is a counterbored hold I've got it flipped over where the smaller diameter is up you could do it on the other side it really doesn't matter what I'm going to do is I'm going to put my pins in here like such so I come in here with my dial calipers now I'm going to measure across these and when I do what I'm getting is a 269 thousands across and I've actually measured them I measured all of them and went around there and did all three measurements and I'm not going to do that right now but trust me it's 269,000 sore 2 inches 2 inches 369,000 so I wrote that down and that's the measurement across there so now what we do is some good old-fashioned math to calculate what the distance is from center of this hole to the center of the part so let's draw this out and we'll go through the process of calculating the what we need so I've got a three hole pattern and we'll draw it out like such I know that these pins are five sixteenths inch which is so 1696 equals zero point three one two five inches okay I know that when I measure across these that this measurement is two point three sixty nine inches okay so what I'm going to do is we're going to treat this like a triangle I'm gonna put a little X in the center of those holes and we're going to draw a triangle okay each one of these this is a 60 degrees on all of your angels here they're the saints and so the first thing I want to do is instead of going from the outside of the pins I'm going to work off of the Centers of the pins so what I need to do is I need to subtract the diameter the pen the 5/16 inch from this number and when you do that you come up with two point zero five 65 inches from Center to Center and again I know the pins are 5/16 I got a half on this side and a half on this side so I need to subtract twice the half or just the whole number there that's what I come up with so what I'm after is the center here so I'm really what I'm needing to know is the radius from this Center down there and I don't have a good way of doing that but we can draw some more triangles here and use some geometry to figure this out so now I've got two triangles in here they're right triangles now which makes the math a little bit easier I know that this leg here is going to be half of this number which is a one point zero two eight two five I know that this angle is 30 degrees right here I know this angle is 90 degrees and this angle up here will be sixty degrees we know that because we can add them up the angles and they're going to be a hundred and eighty degrees or 180 for the total of your three angles so now it just becomes simple trigonometry and if you go back to your high schooler remember when you said I'll have to learn this trigonometry I'm never going to use this well guess what we're going to use it so I know from going back and looking in my old trigonometry book because I don't remember this formula I probably should but I don't that to solve for this what we want to do is we want to solve for the hypotenuse I'm going to call it X here okay we're going to solve for the hypotenuse and the hypotenuse so the formula for that hyp the hypotenuse equals x okay we're going to call it X it's going to be the adjacent over the cosine of the angle okay so we're going to work off this angle down here so X we're going to put in the adjacent is going to be not the hypotenuse but the other angle so it's going to be one point zero two eight two five over the cosine of 30 degrees okay so now we've got algebra we went from trigonometry to algebra so the first thing they do is calculate what the cosine of 30 degrees is and there's a couple of ways to doing that so the first way we can do this is we can use good old-fashioned trigonometry tables this is when the way it would have been done many years ago before computers and scientific calculators and if you look inside your Machinery's handbook you got all these tables are all right up in the book where you can look it up so I've gone to my mathematical tables the natural I've gone to 30 degrees which is what I'm working on here you know it's zero minutes it's an actual 30 degrees you know we got 60 minutes in that 30 degrees and you can look it up for any of those minutes but we're going to look at zero the cosine of that is zero point eight six six zero three so another way you can do this is use your scientific calculator if you have one that has the trigonometric functions built into it so to do that cosine of 30 degrees we'll put in 30 I'll hit the cosine button and look at their thanks are going to take it out to a lot more significant digits but it's the same number we came up with zero point eight six six oh and they rounded up the two five two three so we're just going to go with that same number we have there right out the table we're going to use the zero point eight six six oh three so now again using my scientific calculator I'm going to do the through the math so I'm going to take the the top number there one point zero two eight two five and we'll divide it by the cosine of 30 degrees which is 0.866 zero three and what does that come up with so x equals one point one eight seven three and that's in thousandths of an inch so you got it down to three ten thousandths and when I look at that number again being familiar with my decimal equivalents I know so another way you can do this is use your scientific calculator if you have one that has the trigonometric functions built into it so to do that cosine of 30 degrees we'll put in 30 I'll hit the cosine button and look at there it's actually going to take it out to a lot more significant digits but it's the same number we came up with zero point eight six six oh and they rounded up the two five two three so we're just going to go with that same number we have there right out of the table we're going to use a 0.866 oh three so now again using my scientific calculator I'm going to do the math so I'm going to take the the top number there 1.0 2 8 2 5 and we'll divide it by the cosine of 30 degrees which is 0.866 0 3 and what does that come up with so x equals 1 point 1 8 7 3 and that's in thousandths of an inch so you got it down to 3 10 thousands now when I look at that number knowing my decimal equivalents I know that 3/16 inch equals 0.1875 so you know we're off by 2/10 of a thousands from being an anomoly measurement I'm sure that you know just in the air involved in this that that number supposed to be 3/16 of an inch so basically what we're looking at is a measurement of 1.1 875 so that tells us go back up here to our chart the hypotenuse here that tells us the radius from here to the circle if I know the diameter I need to double that so one point one eight seven five times two equals two point three seven five inches which is two and 3/8 inches so there you go a quick refresher course in trigonometry and algebra I had told Mike that the diameter was two and a half inches it was actually two and 3/8 so I was off a little bit and that messed me up so game-playing now what we're going to do is we're going to take this back out to the machine shop again and like I've already mentioned we're going to read rill the three holes in here and hey we'll call this a feature this this instead of being on vests up we're till everybody's as a feature these these dividing plates be used on two different bolt pattern's how about that they're very special that's what I'm gonna keep telling myself but we'll read rill these out on the right whole pattern and then we'll counterbore them like we were going to do these holes and everything should be good to go out like I said we can completely salvage the situation but it is a little frustrating to have made a hat a bozo moment and made a mistake like that but hey it happens to the best of us and at least I can salvage these I'm not going to have to start over so when we get out to the machine shop because you guys had so many questions on how would you do this manually I think what I'm going to do is take a little bit of extra time and I'm going to show you two different ways to put that whole pattern in there one way is is like the way I made my dividing plate many years ago is setting this up on a rotary table and basically finding the center of the part will move out that radius the proper way out and then use a rotary table to dial in the angles the angle sixty degrees between each one of these and drill the holes out and the second way is again we're going to put it in the vise on the milling machine or something to hold it may just clamp it down the table don't know yet again we'll find the center and I'm going to use my digital readout which actually has a bolt hole function built into it that will drive me to the individual coordinates to drill these holes so the first method I think I'm going to show you guys is using the rotary table to reel out this whole pattern and first thing I got to do is I got to get my rotary table set up the center of the table is in line with the center of the quill on here so I can zero that out on my digital readout and so what I've done is I've got an indicator on here that I can sweep around the outside of here and I've already got this centered up so everything is pretty much running on zero there's a little bit of a you know movement as I'm going around but that's about as good as I can get it centered up and it's it's I would say it's easily within a thousandth on the zeros so I'm happy with that and again another opportunity to use an indicator it's a little test indicator that I've got set up to sweep around this and it is set up on 0-0 and I have got my digital readout zeroed out so now I've got my index plate set up on the dividing head and our on the rotary table excuse me and I put some one two three blocks up underneath it to just kind of get it up off so that my drill bit has clearance I'm not going to drill into my my table and then again using the indicator I've gone around here and got this running true that the rotary table is already centered now when I come in here everywhere on here I touch I'm going to zero all the way around and you can't see it around the rest away but I have tested all around so now when I rotate this that is running perfectly true so we should be ready to go now and go ahead and start drilling out our holes rotary table is centered on the or was centered on the center of the drill here and then this plate was Seguin centered on there so everything is rotating everything is uh within a couple of thousand seen you buddy probably thousands and a half checking everything and that was turning the table checking all different angles which I'm happy with so what I've done now is I've actually moved the the drill the center of the Chuck over the distance I want to put my new hole pattern so the old moussa two and a half inches this one needs to be two and three eighths inch so I'll move it over half of that which will be one in 3/16 or one point one eight seventy five and so I've got this centered up on the new hole our distance over here and on the using Maya digital readout of course my as I think I mentioned before my digital readout only reads that the tents only reads an even number so I just went with 187 for so I'm a you know that's just the resolution is 210 thousand so that's close enough for what I'm doing so now I've got a center drill in here I'm going to drill a center drill it will drill it I've got on my rotary table my angles actually went through here and marked them all so I can easily go back to them you know if I were doing all these individual holes what I'd have me is a list of all the different angles I needed to dial to and I'd have to go to each one of those spinning it around in a drilling so on this one we're 120 degrees apart so again I would just take 360 divided by how many divisions I have and that's how many degrees I'd have to turn the table for each of the holes so let's do this one enough of spot now I've got a 5/16 drill bit which is a size hole we need through there go ahead and change drill bits or put my Center drill back in and we'll go to the next angle and again I've already marked my rotary table of course I zipped right past it but that's the angle right there so now we'll go ahead and drill this one all right that's got that done and you can see you know if I were doing the small holes it would be the exact same procedure but again I would have to dial in all those angles it's very time-consuming it's very tedious and you have to be very careful that you don't miss one when I did this before many years ago I actually had a list and I had every angle on my list on here that I would dial to and then I check it double-check and actually had someone else check it behind me because you just couldn't be off so anyway that's one way of putting a whole pattern in you know the drilling part here went fairly quickly truth the matter is the setup took a really long time you guys just saw a few seconds of it but I probably spent over an hour getting the rotary table centered and then getting the disk centered on here and every time you flop swap a disc out you got to get it recenter if I were doing a bunch of these I could build a little jig that it would just sit down on top of but for a one-off jobs is very tedious and time-consuming all right so I'm setting up for the second plate now and again I'm going to use a different method this time just to kind of show you a different way of getting the same job done very often I've talked about your one way to skin a cat and I'm going to show you two different ways and there's probably even more ways that you could do this this is two ways that I'm set up in my shot the drill these bolt hole patterns and the second method is going to be using the bolt hole function on my digital readout and so the first thing I need to do is in this way I've taken it off the rotary plate I've just bolted it down to the table again I got it up on some one to three blocks just give me some clearance but the first thing I need to do is get my spindle centered up on the center of this part and I could use the indicator like I used before but again I'm going to show you another little trick and this is what's called a coaxial indicator so the way the coaxial indicator works is you have this little probe in here and as it moves in and out you can see on the indicator face it moving around now one thing that I will caution you is that even though we've got a scale on here this is not necessarily measuring in any particular increment it's it really depends on the angle and the length of this rod that comes out and depending on that it's it's it can it can be a difference as far as moving your table so many thousands clean it up so in this situation this indicator is going to give you a relative amount of run out in something by using that dial so basically what you want to do is turn this thing on and when you do you see the dial down there it's just spinning around you can hold this and you want it running zero right now it's running zero but as that thing starts hitting it's going to bounce around I'm going to do now let's go ahead and we'll drop this down into the the hole we want to measure there we go and we'll turn the mill back on and you can see it's bouncing around so now what I'm going to do is just adjust my tables and get it to us we take as much of the air out as we can so you have to watch it you can you move your table you're going to see the needles either getting closer together all right or getting farther apart I'll run out is less once you get to a certain point the run out will increase and you just want to get it down to where you're getting the minimum amount of run out on an axis and you co fine-tune it in a minute and then go to the other axis and do the same thing just roll it around and see get it running zero there we go now we're getting in there little bit better ma Vermont to run out and go this axis I went to fill it too far we fine-tune this axis wrong way we're getting real close right here alright that's just barely bouncing around I'm gonna call that good what we do is we'll did center out the digital readout so back on the digital readout we're just going to zero out those to the X&Y axis so now the mill is set up on the center so now that we've got the center identified in this part I've got my center drill in here and again we're going to go to the digital readout and what we're going to do is we're going to tell it to put in a 3 volt whole circle and it's just going to drive us to the coordinates using the digital readout so over on the digital readout what I'm going to do is I'm going to start off by hitting the vault whole circle button right there and we'll say enter and it's going to ask me for my zero zero coordinates now if my coordinates are numbers I can type them in in this case it's on zero zero so I'm just going to hit enter for the y-axis I'm gonna hit enter for the x-axis it's going to ask me what my radius is my radius again we're going for two and 3/8 diameter so be half of that which is one point one eight seven five so I'm going to type that in one point one eight seven five double check that that looks good hit enter all right now next question is going to ask me is the starting angle and if I look over on my part the way I've got this out is basically it would normally start with my first hole be right here I want my first hole to be up here at 90 degrees some will put in 90 degrees it's my first angle and then it's going to ask you for the number of holes and this is a three bolt hole pattern so I'll put in three and what you see next is the coordinates of where I need to go to for my first hole so I need to move my y-axis over and inch in 3/16 so we'll loosen up our table and we're just going to take that to zero it's going to basically for each hole it's going to steer you to where you want to set your table to zero zero it starts beeping when you get close all right so we're ready to drill our first hole I got my center drill in just kind of come down that Luke serves that right on put my drill bit in alright so now I'm going to hit the right arrow button and that will take me to my next coordinate so we'll start by taking this from the zero right there and then bring my other axis to zero I found that in the way alright and that looks right on where I need to be from my next hole I'm Center drill it first a little dimple in there to make sure in the right spot that's it we'll just clear out and that will actually show us the actual coordinates that we're at but our boat hole pattern is done so this method that I used using the digital readout is basically the same method that the CNC mill use that Quartet basically you start with the center of the part it calculates the coordinates for each one of the holes in here but instead of you having to manually drive to each one of those coordinates on the CNC mill the servos and the computer is going to do it it's going to do it very accurately and very quickly to get the same job done but we've got the bolt holes drilled here now so we should be ready to counter bore these I've got my counter boring tool which basically has a pilot on the bottom and a flat bottom the larger diameter that will allow this bolt to go down through there and I stopped so I've got it set up I've got a depth marked over here on my scale where I can go down I put a little stop over here just to give me something that's this thing is rotating just to kind of hold it in place and we're going to cut them I'm going to slow that down a good bit I like to run my counter Bors was on the slow side just so it doesn't burn them up and we'll leave that up I'm in here and get it done the run out is it's not really run out it's just the tool it's the cutter itself it's floating a little bit we're just going to let it go down according to my mark that should be it just verify drop the screw down in there and actually I think I want to go just a little bit deeper not fly deep enough I just need to give it enough clearance for that vault to clear - that looks like all right that looks good I have a marked on here the little Sharpie pen the whole set that need the counterbore and we'll just continue doing this on the other one so we haven't done so I've got the new dividing plate installed on the dividing head now everything appears to be looking good it goes into the holes like it's supposed to of course you can see it turning over there so this should be ready for our dividing job so I just need to get a day I can come in here and get that done and we're going to be doing a gear repair for a fellow YouTube viewer so so that'll be a wrap on another project got are at least two of the dividing plates all finished up here mike is going to be getting me the other four and then with these two I have the main ones I need the other four kind of oddball sizes but hey I fear as long as I'm making them I'll go ahead and get the whole set so thanks to my little bozo moment we had to make some lemonade out of lemons but in the end it's not going to matter you know we got a couple extra holes they don't hurt anything other than maybe the appearance a little bit but they're fully functional and we're ready to go now so that'll be it thanks for watching we'll come back with a dividing head job in a gear repair job coming up soon using this knt dividing head you

Channel: Keith Rucker - VintageMachinery.org

Views: 106,142

Rating: 4.9298911 out of 5

Keywords: Machine Shop, Machinist, Milling Machine, Vertical Mill, Shop, Vintage Machinery, VintageMachinery.org

Id: aMUNPqofCII

Length: 37min 27sec (2247 seconds)

Published: Fri Jan 22 2016