Improving the vertex rotary table - Part 1

[Music] Hey welcome back to my shop back when I bought my milling machine the optimum MB for tabletop milling machine I also bought this verdicts rebranded as optimum rotary table this is a made in Taiwan unit and it's it's quite good I posted a teardown video after Sky quite some time ago and I will put a link down in the description to the teardown and when we had taken this apart most of the details and this rotary table were quite good and well made but I wouldn't be Who I am if I wouldn't go for a complete overkill rebuild on piece of equipment that I have so I thought about it and we're going to take this riveting table apart we're going to scrape all the mating surfaces we're going to tighten up the plane bearing the radial bearing in here which is just sliding bushing a shaft riding in a cast-iron bushing we will tighten that up and we'll scrape the actual bearing surfaces after rotary table and rotary table itself yeah that's the general plan and some some small things I want to do I want to cut a key way in here that mates up with the keys of my milling machine or will feed t-slots of my milling machine for alignment and a few more little things so let's go over to a milling machine and I will show you what I mean with the some of the key slop okay first thing you might notice is that the holes in the base of the rotary table do not line up with D P slots of my milling machine and that's really annoying you could use one of the holes with a stud and the strap clamp back here but add even more annoying so what I did I meet these two clamps out of carbon steel these are hardened and tempered to roughly 45 Rockwell so they last and those slide in and clamp the rotary table down here on this flange against the table and that works quite well at least for my purposes this is most of the times way stiff enough if I need more a more rigid setup I can add a third holes down clamp on the rear side of the table server table that is and a leaf and I'll leave those clamps always set up with the screw with the t-nut and with the clamp itself so when I use the rotary table I just take out those two clamps pack them in the slot and good to go that makes for quite a fast transition to the rotary table same when I use the rotary table in a horizontal Kurd configuration like this as a peanut hacks crew and a very heavy hard washer these are also turned from 45% what point four five percent carbon steel and harden them tempered and deep go in here and lock the table down same on the other side those also always stay together in a box together with the rotary table so while the alignment of the table in the horizontal position is not relevant you could clamp it this way this way or this way onto the table and wouldn't matter because the work is rotating 360 degrees around it only changed your zero setting but apart from that the matter it matters if you have the rotary table up in a vertical position and you want to do accurate work rotoiti will need to be aligned square to the travel of the axis and on my rotary table I have have surface ground this lower edge here so I can do rough alignment with with a machinist square or run an indicator along this edge for precision alignment but that's still one step more to do before I can start working what I want to do is I want to cut the key slot in here into the base of the rotary table well where I can use a pair of precision precision keys for alignment these are hardened and ground to very close tolerances you can buy those readily available era ground very precisely and they fit into the keys of a machine and you can use them for semi accurate alignment of tooling it helps if you have two of those keys quite far apart but that's not possible in the case of the rotary table coffee the base is only that wide but I still can slip in two of those and then I can push the rotary table up against the keys and it will align itself quite angry we have to do all the machining all the real machining and material removal on River table before I start to scrape anything on it because any machining will cost distortion in the cast parts yeah and to do the machine will take the rotary table part so it's not so free can have you when I have to lift it around on the machine in [Music] he okay while they're at disassembling I also going to take off the the warm gear from the table but after rotary table spindle with the round spigot which gives a radial radial alignment in the the housing and I'm just giving the spigot here a quick check with the micrometer and it's out of round not very much it's it's 40 5.0 one here forty one forty five point zero five here and 45 0 here so it's about one hundredth of a millimeter out of round and we will fix that too while we have the part we will compare the diameter of the spigot here to the bore and the housing so already measured the dot and the spigot is forty five point zero one and the bore in the housing I'm just taking a rough measurement with the two point internal mic if 4505 so we have four hundreds of no meter clearance clearance or clearance its clearance so I'm surprised that that the the difference between those two diameters so big while it does not affect pursuing after a rotary table as much as I would expect I could only measure and play in the spindle of about one hundredth of a millimeter and I blame this to the heavy oil I run in this in the rotary table the oil film around the spigot in the bore seems to be stiff enough to keep it centered enough and in place so the four hundredths of a millimeter gap between those two parts which is almost two thousandth of an inch doesn't affect the work but that said I want to tighten this up I think I'm going to machine this diameter down by one or two millimeters in diameter I will machinist leave some some steel I'm not sure about the material combination yet but I will lock type the sleeve on and then machine and lap it to final diameter and I will do something with the bore but I'm not sure about lapping the bore and cast iron because cast iron is quite soft and I don't want to embed any kind of abrasive in the bore so I still have to do research about lapping cast iron okay I get me through the routine you'll back over on the milling machine and I centered it over the two T slots and I will cut the key way into the housing of the rotary table back here and that already did the calculations worthy slop has to be it's forty two point eight seven millimeters so forty-three to this side of the slot and above machine and matching key to my machine out of this piece of tool steel I will harden it and then I will grind it to width so it's a very close very tight fit in the teeth lot and if I remember right the slot comes machines on this machine are 14 millimetres this is a fourteen millimeter gauge block stack and it's a rather loose fit so we have T slots and the nominal dimension 44 the slot itself a is tolerance with h84 lineman and clamping T slots H 12 which is a far looser tolerance for T slots that are only for clamping let's assume the slots on this machine are for clamping and alignment so H eight at 14 h 8 go into [Music] tolerances I so to Lansing let's see large 8 8 nominal dimension 10 to 18 h8s let's write this down it's 14 [Music] plus 27 plus zero and this means that our slot can be the numbers in the tolerance tables are in thousands of a millimeter so our slot can be can have a tolerance of 14.000 as the smallest dimension and fourteen point zero to seven as its largest dimension so we should be not be able to get a 14 point oh stream on the gauge blocks back into those slots if they are to spec which is question on a Chinese machine I have a 14 point o3 only the stack of gauge blocks here and I cannot slide it into the T slots so that's good so that means that the slots are to spec let's try a 14 point o2 millimeter gauge block and this is a nice fit if you don't drop the gauge block stack so the 14 point o2 millimeter gauge block stack is a very very nice sliding fit in the T slot that means that we're going to machine the key to 14 point oh two millimeters after we harden it of course okay that was a very quick X course into tolerances and reference book and so on so we'll just start by machining the T slot into the base of this rotary table I don't want to make this this key slot in the rotary table too deep because I don't want to wheat the casting too much okay to clamp the casting I bolted a box parallel to the table of the machine it's aligned in Y X direction already and take my casting order housing and it will bold it against box parallel just like this with a long stuck through there okay get it bolted against the box parallel now I'm leveling up top surface okay let's check or alignment and obviously the surface dropped still dropping and nods risings that's looking good we start at 22 over here and when we traverse to the other end we are still at 22 maybe half of a hundredth of a millimeter I added a second clamp down here so the setup is safe with only one step in the center the work could rotate and the second clamping strap clamp down here was the bolt through it this can take up the torque as we rotate the part and mess up the job so okay when I machine the key the key slot into the base of the rotary table I want it to be square to the base of course otherwise it would be useless so it broke up in to thousands of a millimeter dial test indicator and I'm rechecking my alignment I already tweet the setup slightly by loosening the bolt that holds the Box parallel to a table and I knocked it slightly into alignment and when you watch the needle of this rather sensitive indicator you will see that you see nothing just double check okay most of the needle jittering is surface roughness but we are pretty much zero that not song and yet indicator revolving contact see so I think that's pretty good aligned for the job at hand okay I'm using a six month three flute carbide end mill to cut the slot to a width of 14 plus a little bit okay I got a 14-point of the three millimeter gauge block stack here and it should be very nice tight fit in the slot and it slides all the way to the bottom of the slot with a little bit of wiggling so that's a rather tight fit that's a rather tight fit that I like I prefer to to work besides the slot of the stone if the fit is too tight but I don't think that that is necessary Oh I think I did everything that's possible in the setup I ran the chamfer mill around the edge a machine the slot for the key and a grilled tapped tooth m3 threats to hold the key in place so let's tear down the setup and proceed on ok stoning get back up the rotary table before we go to the surface plate using a diamond ground aluminum oxide stone surface ground to stone flat on one side using a diamond wheel on surface grinder and this works really well when stoning precision surfaces I always cringe when I when I saw people using some random stone like like this corundum stone and going frantically around a machine table or something like that and scratching it all up so I never visited actually I always used the palm of my hand to feel as there are somewhere a being or something that needs to be stoned just in the area but [Music] the precision ground stoned you can buy these and Robin Arryn said he showed them in his video and he wrote somber in the comments a little bit about them the surface ground still is not as aggressive cutting a stone that's normally dressed and behaves a little bit different if you if it's six flat on a flat surface it's really only sliding around [Music] but as soon as there is a Bing or something like that in the surface the stone starts to act differently and it will see or feel a cutting actress down on the erase area and when take a close look you will see a highlighted area fresh exposed metal around the big naturally the raised up metal gets removed just imagine like this ever a flat surface and it gets hit with a with a point the object like a center punch we'll look like this in cross-section it will be raised material here and here and a deeper area and we only want to cut away the raised area with the stone we do not want to alter the surface in general what you can also do before you if you see the thing before you can take a ball-peen hammer and you can pin back some of the material before you stone it that way you don't lose as much material and you can close up the thing more or less so I use an I use it what and of course you do not use such a stone to to hone your relief tools because first of all it doesn't cut as well and second you don't want to mess up the precision ground surface if I hold straight edge up to this this is their flat in two directions I hold up a stride a straight edge to the small stone here losers childhood up in every possible direction I have my new-to-me me tutorial hi cater to set up on the surface State this is a one thousandth of a millimeter indicator these are built by Marv for four meter to actually say assess exactly that on the backside made in Germany buy more for me tutorial which is quite neat didn't know that Victoria made that resell measuring equipment from more I always thought they are competitors but seems that there is some some kind of working together so this guy's is super nice this type of indicator has only a very limited travel it goes from minus 500 700 to plus 500 so it's 1/10 of a millenary complete travel and they don't have a backlash this time a normal indicator has a backlash of 1/100 of a millimeter indicator has a horrible amount of backlash these don't so you bring them onto the surface if you want to measure and you have a fine adjuster here so you can throw them out it have about plus minus 5 hundredths of a millimeter adjustment and the fine adjustment is one of the nicest I have ever used compared to the fine adjustment often of an indicator stand this is like this is like bother using the fine adjustment on most indicators thanks like using a battle-axe for brain surgery something like that but this you can pinpoint your zero so nice without a problem and i'm using the heavy meters hero height gauge with the twin columns as an indicator stand for it and that seems to be Richard enough to do that job so I walk my way around and I have written out all the difference in height in thousandths of a millimeter and as you can see we start at zero it drops slightly over here to minus three hundredths of a millimeter then it goes back up and a divot of three hundreds over here and that goes up back zero so and all those numbers in 1070 there so what the numbers tell me is that a bottom surface and a sliding surface for the rotary tables for the actual rotating part is pretty good parallel there is as I said the three cable is out of the box really very nice piece only thing that annoys me slightly is the big play and the bore but parallel isn't wise it's a nice piece and while I will scrape that I will scrape the underside and this slide in this bearing surface here I will not change the geometry because that's okay that's well within five thousandth of a millimeter at two ten thousandth of an inch roughly so I'm going to single bore single point for he a central bearing door diameter and then I will go from there I already checked it at slightly Bell mouthed to the bottom which is also bad but we will well sort it out we'll take the wall hop the boring head or my other smaller boring head in google clean up this whole make it round and cylindrical a post by a bit of talking I clamped the the rotary table casting flat onto the table and I have already my small boring head that can pass through the bore in the spindle and I'm centering on the original bore or I already centered as you can see we start here with zero I spin it around we get also 0 plus parallax error which you cannot see on video or you see the error on video but I can show look down straight on the dial so there is no this is this is 0 90 degree to the back and you can see that we have 0 back here to now spin it again 180 degrees to the front and we get 0 in this precision - that's the board center what I want to check - because we're boring with the quill and the power feet I want to check the tram against this surface the sparing surface which is within reasonable tolerance of parallel to the bottom surface we measured it for is less than 5000 of a millionnaire out of parallel so I can consider this surface right now as parallel oh and I found something out when I tighten these table locks down too hard I can bend the table by five thousands of a millimeter it makes a bow in the Y direction it gets loop like this if I cram too hard on these table locks same for the cross piece the y axis if I lock access too hard at bends that's the problem with direct acting locks not the blade type lock you would have on a chip borer or on a chick grinder so that's also a reason why should not overtighten stuff on machines like tail locks or quill locks or draw bars or everything nothing on a machine needs 100 Newton meters except for ER kollek's must take ridiculous amount of torque but that's another topic adjustment screws and stuff like that do not need to be over tightened like crazy okay I've double-checked ever saying five times and know about the bore central hole I I set the tools that takes a very light cut and that's all I need I just want to clean up the bore and make it nice round and straight so let's go 300 rpm and you're feeding the 30 millimetres per minute okay I will clear the tool slightly so don't scratch the surface when I retract cool okay here you can see the surface finish we camped and this this looks really good I will take a close look if we clean up the whole surface but looks promising I took about 1/10 of a millimeter on per site and that should have cleaned up everything okay I want to show you the tool I used for boring and that's just a high speed steel cobalt 8 blank and it's crammed like a turning tool and I left the surfaces with a stone - very very good finish and I also hand lapped a very small radius on the cutting edge you can see this line of light here that's the radius the radius this down here in this on this cutting edge so most the radius I get the throughout a good surface finish and also you can see that I I don't bother with lapping the whole surface it's just important to lap all the way up to the edge the the rake surface here does not need to be super high polished when you're working with steel or cast iron if you're working with aluminum a high polish on the surface can help with chip havoc evacuation but I don't use a real number so [Music]

Channel: Stefan Gotteswinter

Views: 90,211

Rating: 4.925602 out of 5

Keywords: rotary table, vertex, rundtisch, teardown, hardturning, iso tolerances, teilkopf, dividing head, milling machine, boring, wohlhaupter

Id: DTRc5B1HcRc

Length: 36min 50sec (2210 seconds)

Published: Tue Apr 25 2017