Center a Rotary Table in Under a Minute Without an Indicator

A novel technique to center a rotary table in under a minute without using an indicator.
Check out Metalworking Fun at metalworkingfun.com.

[@sdftrd]

This technique really saves me a LOT of time. And it's so common sense simple! Thanks for posting, Tom

[@TomsTechniques]

Thanks Jon. I'm basically lazy and come up with these ideas to make my life easier. I'm glad you like them. Tom

[@TomsTechniques]

Thanks Cliff. It's good to hear that people are using the techniques in these videos. Tom

[@532bluepeter1]

Dear Tom, I wish to thank you very much for your videos again. I made a tapered pin in this fashion for my somewhat smaller rotary table and milling machine. The bore of my rotary table is a No.2 morse taper so I turned a pin with a No.2 morse taper one end and a 1/2" diameter the other from stainless (I hate the rust fairy) in the three jaw chuck at one setting. Centreing the rotary table is now a doddle. This idea is a peach. This set me thinking though as I had to mill a radiused edge around some holes on rope eyes that I was machining. I turned a Morse taper 2 plug for the table with a 3mm bore in it. This means that I could turn a pin with diameter 3mm one end and whatever was needed to fit the part on the other to centre the bore on the table before clamping it to same. The pin is then removed leaving access to the bore. It worked well. I also want to say thank you again for the video on grinding drill bits for brass because having honed all my drill bits for steel I was having a torrid time with snatching. Well, having watched your video I bought another set of bits to dedicate to brass and having stoned those that I needed as I went everything was in apple pie order since. So thank you. If you ever visit the U.K I reckon that I owe you a nice warm beer!

[@TomsTechniques]

Thanks Jack. It's always good to hear that the videos are being used. I am of Welsh ancestry, so I would love to pay a visit to you fair country, in spite of the warm beer thing ;). Now that I'm retired, that just moved a bit higher on my bucket list. Tom

[@rcwarship]

Yeaaaaaaaaaahhhhh! I've used your mill vice aligning method & love it. You've outdone yourself with this one. Gotta get a jig made. Thanks for Posting & Best Regards, Jon

[@brentbarnhart5827]

Tom..... I did the same exact thing. I'm not the fastest machinist in the world, I'm an engineer that happens to have a machine shop and I started doing similar things, in fact, made myself exactly the same thing. Didn't take me much time now to center up. (Believe it or not, I found one of the "end mill holder" style mounts, with the set screw in the side.... one that is ALMOST, perfect for the turn table. I made one up, because even though the end mill holder was close.... it was a hairs difference. but I could get darn close with it. Your video has me adding a taper to my current one. I made it a snug, hard precise fit, but I think the taper is a better idea.

[@RedlineRennsport]

Tom; I'm a new subscriber to your chanel, and am bouncing around at random. I'm finding your style fits mine quite well. Get it done, efficiently! As a moderately dense noob metal mangler, I have wondered about doing many different basic tasks, and this was one of them. When I saw you use this doodad on the carriage stop vid, I had to come back and watch it, and that I'd be making one. I had this very same idea for locating the table, since I do similar with drill bits to "center" existing drill holes. It is very nice to know I have some similar insights. Please continue just as you are. Priceless. Now, off to the vice indicating vid!

[@TomsTechniques]

Glad you are enjoying the videos and thanks for watching. Tom

[@MyIvank]

Great video, I machined a blank end arbor and basically bolted down the rotary table the same way you did. It's more than good enough for alot of hobby work I do. But if perfect accuracy is needed, I'll use the co-axial indicator.

[@TomsTechniques]

Thanks, I'm glad you enjoyed the tip! A lot of these inserts have been made and it looks like you are next in line. Tom

[@onehot57]

Thanks Tom I’ve been using that technique every since I got my rotary table, works well enough for the girls I go out with!

[@TomsTechniques]

Exactly. It's a quick set up for less precise applications, but will never replace an indicator for the tight stuff.

[@TomsTechniques]

Yes, a hardened taper would be better, but I don't own a toolpost grinder. For the amount I use it, the brass one works pretty well. Glad you enjoyed the video. Tom

[@rogue277]

At first, I was asking myself "why not just indicate the center of the rotary table?" Then I watched the rest of the video and was rightfully impressed. Well done!

[@TomsTechniques]

+rogue277 Thanks for watching. (the whole thing) :)

[@superrodder2002]

my rotary table has a .500in center hole so I just use a short piece of .500in ground shaft. it fits the hole so close that I have a vacuum when I try to remove the shaft and it comes out with a pop sound. Also if I want to install a chuck on the rotary table I tighten the chuck on to the shaft sticking out of the rotary table and it will be centered as accurately as the chuck jaws are

[@TomsTechniques]

That's the same principle I use to center parts that have bored holes. I select a gauge pin that's a tight fit in the hole and grab that with a collet. Thanks for watching. Tom

[@ninalli]

That was so simple but so totally cool!! Excellent tip! Please show more.

[@byronrace]

Very slick; and plenty accurate for anything I do, thank you.

[@TomsTechniques]

I spent some time proving the concept before making the video and was pleasantly surprised at how accurate and precise it was. Tom

[@Mentorcase]

So easy and so accurate, I love it.

[@10223220]

This is a great technique and I think it's not quick and dirty I have been doing this for years glad you can get this out to everyone

[@Gottenhimfella]

Good thinking, Tom ! Unlike most of us, you make youTube a better place. I've only just stumbled across your stuff but so far I haven't struck one I didn't learn something worthwhile from, and this was no exception. I tried to guess before watching what it was you were going to suggest, and what I thought was similar, but might be worth mentioning: I was thinking of something along the lines of a pipe centre as fitted to the tailstock of a lathe, (the fixed variety, not spinning) either with a tapered shank to match the spindle, if it's Morse or R8, or just cylindrical to fit a commonly used collet (your 1/2" being the obvious choice). The idea is that it would engage with the entry chamfer to the register hole of the rotab. The idea would be to push down increasingly hard on the rotab with it, as you nudge it towards centre, (if it's a really heavy unit, it's easier to nudge with the mill table handwheels). My first thought was this downforce might make the rotab less likely to shift as the clamping nuts or bolts were pulled down hard. However this is probably not realistic. As you say, they probably will not move the rotab, but if they want to, I don't think the stiffness of the machine - and this setup - would be sufficient to prevent it. If necessary, the chamfer in the faceplate could be trued up very simply by using a countersink (preferably a large one, in good condition, but no need for it to be anywhere near as big as the hole) and offset the rotary table in order to take a light cleanup cut with one side of the countersink kissing the chamfer, while turning the faceplate with the rotab handwheel ('climb mill' for better finish).

[@TomsTechniques]

Thanks. I spend a lot of my time outside the box, so you'll probably see a lot of techniques here that you won't see anywhere else. Glad you are enjoying the videos. Tom

[@KodyBear5605]

My 6" Phz II center hole is an MT2 taper. A drill chuck arbor, with a straight shank, works perfectly for your procedure. When I need a lathe chuck mounted, I use a large drill bit with a MT2 taper and simply lower the chuck over the drill bit. By tightening the chuck on the drill bit, it'll self-center perfectly on the table. Now I clamp down the chuck to the table. Hope that made sense... Thx, Tom

[@TomsTechniques]

Yes, that definitely makes life easier.

[@FredMiller]

Great tip Tom. A real time saver for sure. I know what you mean by having doubting Thomas's out there. Thanks again-

[@TomsTechniques]

I'm building a website that will feature project tutorials and that might make a good starter project. Thanks, Tom

[@bangthehankers1985]

Tom, you’re a treasure. Really great stuff.

[@cliffjones1511]

Thanks Tom I made one today. works great I'll now use the rotary more. Cliff(SC)

[@lbcustomknives]

Hi tom, I have a project coming up for a customer that I have to make what we call a pivot ring what I would like to ask please.. Is that if you could do a video pleas of using a milling machine to to mill a round coller that will go around a 1/4 inch pivot hope this makes sense if you could help with this please I would be eternally greatfull I have the mill a rotory table and laith chuck that goes on top of that that came this week. The material I will be using will be similar to carbon fibre called g10.

[@TomsTechniques]

You are welcome. Glad you liked the tip. Tom

[@RickRose]

Excellent tip. Just got my first rotary table, so I'll be using your idea. Thanks very much.

[@TomsTechniques]

Center the table as shown in the video, then center the cylinder on the spindle as follows: Mount a pin in the spindle and offset one axis half the diameter of the cylinder minus half the diameter of the pin and clamp a parallel to the table against the pin, roughly perpendicular to the axis you moved. Now do the same for the other axis. Now you can locate the cylinder off the parallels, clamp it to the table and remove the parallels, leaving the cylinder on center. Or buy an indicator. :) Tom

[@RosaStringWorks]

Cool idea, thanks. Got my wheels turning... no pun intended.

[@Banshee350speed]

Excellent idea 👌 Going to make one today Thank you sir 👍

[@abednegokatiyo8269]

Excellent time saving solution ... brilliant idea 👏

[@onlooker251]

I’ll be making one of these for each of the rotary tables I have. I’ve tried several methods using a quill mounted DTI and the like - this looks much easier! 👍🙂 John 🇬🇧

[@TomsTechniques]

Thanks, it's good to hear that the videos are a help.

[@keithscott9774]

Thanks very much Tom, love that idea, and I can see me using it a lot in the future. I came looking for RT setup techniques after reading a machining book. The author of that book reckons that unless the RT is very high quality, the accuracy of the taper hole can be off a little to the true axis of the RT. For high accuracy he recommended you do something like clamp a turned ring to the RT and dial it relative to the RT axis so it running perfectly true, then afterwards dial the ring to the mill spindle. Then you know for sure the RT axis is accurately running true with the axis of the mill spindle. I know that is in complete opposition to the point of your video but talking about high accuracy here for less than perfect RTs.

[@TomsTechniques]

I have never seen a rotary table with a center hole that has questionable concentricity, but I suppose the exist (China). You just have to know your machines and their accessories to have confidence in them.

[@ob29295]

Saves so much time. Brilliant idea, and thank you for your time and tips.

[@TomsTechniques]

Thanks for watching.

[@TomsTechniques]

Mark, Ideally the insert should be fitted to your particular table, so making one off site that would fit properly would be difficult. It's not that hard of a part to make. Just bore and turn it in one setup to maintain concentricity and it should work fine. Tom

[@bubbadoolittle2812]

I did this a while ago for setting up my rotary table and it beats the hell out of digging out the indicators and using a hammer to tap the table into alignment!

[@williamcooper1699]

Great indexing video...any chance you'll have a video showing how to disassemble and clean a rotary indexing table?

[@laurentcnc6662]

Great tip Tom, it looks like magic !

[@BasementShopGuy]

Awesome. Another innovative technique!

[@CruiserMac]

Looks like a great idea! You should do a video on making the tool for us rookies, I am not sure how to cut the taper on the brass part?

[@gvet47]

Just found this video and with my luck over time I would end up shaving the brass so steel sounds better but brass turns so much nicer for me. Since mine is MT#2 maybe easier for me to get an arbor and use that.

[@TomsTechniques]

Thanks Fred, glad you liked it. Tom

[@geoffhalstead1811]

Than you Tom. Another BG tip. Mylvank's tipoff using a blank end arbor suits me.

[@Navigator777777]

I like the part about "The Critics". Now all the critics need is warm milk and a bed time story.

[@TomsTechniques]

Lol.

[@DanG-ug1ed]

You did a bit of slight of hand. I would expect your test to be exactly as you showed given how you centered the table. BUT, what you left out was moving the table. You didn't account for backlash. I think once you got it concentric, but not tightened down, you need to move the x and y a bit, set the zeros, and then tighten it down.

[@TomsTechniques]

A digital readout negates backlash. If you didn't ise one then yes, you would need to remove the backlash before tightening the hold downs.

[@vdub5818]

Hey Tom, Any chance of a video of rotary table tricks/tips? Keep up the great work!

[@TomsTechniques]

Absolutely. A video showing an easy way to set up and mill arcs on the rotary table is on my list of topics. Tom

[@vdub5818]

Thanks for the reply Tom. I have used my rotary for only a few things so far, one of them being counterboring for odd size or large size counterbores. It allows me to use pretty much any size cheap endmill to counterbore whatever size I could possibly want. Can't wait for the video!

[@wireedm1]

Excellent time saving solution for setup! But, wouldn't it be more accurate to place the indicator with a magnetic mount on the surface of the rotary table and put the indicator tip on the spindle and then spin the rotary table? I always found that the center hole on the rotary table isn't always true to the center of rotation.

[@TomsTechniques]

Yes that would be more accurate, but it would also take a lot more time. This is a quick and dirty method for when centering a part within a couple of thousandths is good enough. BTW if the center hole on your rotary table is not concentric, you should probably look into getting a new rotary table. Some things, such as the parallelism of the t-slots in your mill table are assumed. Tom

[@TomsTechniques]

It'll be a project well worth your time.

[@jessestrum]

thanks tom i,m a beginner and this is a great start

[@lbcustomknives]

Basically I want to add this color around this pivot the centre hole is 1/4 inch and I would like tho collor to go around that to be around 4 m&m bigger than that I could send you an email of what I need your advice on how to use the mill to achieve this please. Take care lee.

[@TomsTechniques]

You can make a collar on the mill using a rotary table, but it would be a lot easier on a lathe. Basically you would just rotate the stock against the cutter to mill the inside and outside diameters. If you are cutting G10 glass epoxy, it would require carbide end mills. Also be sure to use a vacuum to collect the dust because it is hazardous to breathe. Tom

[@steveb936]

Thanks for that, do you have a link to the vice setup video?

[@charleyjohnson7286]

Interesting perspective thanks for sharing some of your knowledge.

[@bobweiram6321]

Why would anyone think this method is less accurate than an indicator? Also, out of curiosity, what accounts for the small runout?

[@pc2539]

Thank's for showing us Tom !

[@TomsTechniques]

Thanks for watching!

[@dpearson966]

My old shop teacher did this same thing, except he used a 1" ball bearing. Looks good.

[@kobe12345456780]

Thanks for sharing. But I got a question, how do u center a cylinder clamped with rotary table without an indicater nor a edge finder? Only with milling tools? Is that possible?

[@riphaven]

Never thought of that, but I guess that would work. I can say this a four jaw chuck can be a pain to set up on my mini lathe. Thanks :-)

[@axolpolly3366]

very good Tom,very quick,,, thank you.

[@TomsTechniques]

Thanks, glad you liked it.

[@bluecrusader62]

What an awesome technique

[@EitriBrokkr]

great idea, any suggestions for mounting a super spacer, rotary index horizontally, instead of vertically? cause they are a pain

[@TomsTechniques]

I made a similar device for aligning my dividing head. It's a block with two holes bored in it at a right angles to each other with a couple of 1" dowel pins pressed into them. One pin gets mounted in the quill which is left free to float and the other goes into the chuck on the dividing head, which has the angle lock left free. When the chuck on the dividing head is tightened, the angle gets set to zero and the spindle axes align. The head is keyed to the table slots, so that is already aligned. Obviously, great care must be taken ensure that the pins are at right angles with each other and that their center lines intersect. Tom

[@EitriBrokkr]

You sir, are a genius. Thank you, should do a quick video on that, I'm sure others would love to see it.

[@TomsTechniques]

EitriBrokkr You are very welcome. I forgot to ad that since the dividing head is keyed to the table, it must first be centered on the spindle axis, or you can kind of "feel" it on center with the Y axis crank as the chuck is tightened. Tom

[@shamusarms5476]

Brilliant!! Totally gonna use this

[@richardkicklighter1202]

Super, another one out of the ball park!. Thanks! I do believe if the rotary got a lot of use a hardened taper would be best, Most applications can live with .0005 run out. Sure beats monkeying around with dial indicator, or coaxial indicator. I suppose if the half thou really bugged you, a light smack with a small mallet on the opposite side would work ...or not. Screwit!! get to making parts! Thanks again.

[@riphaven]

I don't even have a milling machine (yet) and that is so cool, thank you:-)

[@TomsTechniques]

Thanks. You can use the same technique to center a part on a faceplate or in a four jaw chuck in the lathe. Tom

[@jamesdepaul3410]

Thanks for this clever tip.

[@chrishill6276]

Excelent info. Thanks Tom.

[@machinists-shortcuts]

Could you lock an expanding arbor in the hole for a snug fit. Then drop the collet over its spigot and tighten the collet.

[@TomsTechniques]

Yes, but how would you get the arbor in and out without removing the table?

[@machinists-shortcuts]

@@TomsTechniques I thought that loosening the clamping screw would collapse the arbor.

[@bower230]

Dude... thank you!

[@TomsTechniques]

I don't think many hobby machinists can afford a separate mill for each accessory. This technique is not intended to locate a rotary table to .0001". for that, it needs to be set up using an indicator. Tom

[@sorstudios]

If someone downs this video they must some arrogant freak that wished they'd come up with this idea. GREAT WORK, AND THANKS FOR SHARING THE KNOWLEDGE!

[@TomsTechniques]

Thanks for watching!

[@anthonythomas3231]

Great idea! Why didn't I think of that? Thanks for sharing.

[@TomsTechniques]

Thanks for watching

[@rayjones777]

brilliant idea,, thanks again, great videos ray

[@VeryMuchBlessed]

Good time-saving idea. Thanks much.

[@TomsTechniques]

You are welcome.

[@dennisginser9746]

Thanks for the tip! Can you do a video on tapping into mild steel on a lathe Preferably with a tap bigger then a 1/2-13???

[@TomsTechniques]

+Dennis Ginser A spring center is the best way to tap in the lathe regardless of size. I'm actually thinking of making one as a beginners project tutorial, so maybe I'll demonstrate tapping in the lathe then. Tom

[@dennisginser9746]

+Toms Techniques thank you. I normally use a spring loaded center. I just got a job that wanted me to tap a 5/8-16 with 1 inch of thread and the material is extremely hard to penetrate. I used a carbide drill thinking it was just case hardened and it was hard throughout. Once I got my whole drilled. I went to tap it with my spring loaded center and it is extremely hard to tap. Broke my tap twice and I'm keeping moly d on it and clearing my chip. Any tips would be much appreciated. Thanks tom.

[@TomsTechniques]

+Dennis Ginser You need to use a taper tap for hard materials to keep the chip load down on the teeth. If you use a plug tap, the first teeth takes all the load and will fracture. A four flute tap is preferable to a two or three flute tap for the same reason. Tom

[@TomsTechniques]

Thanks Ray.

[@billrichardson4873]

Thanks for another great video.

[@TomsTechniques]

Thank you for watching

[@francescomidknight8621]

very nice idea tom! thanks!

[@TomsTechniques]

+Francesco MidKnight Thanks for watching

[@poozandweeez]

different story if you needto crank the bokts down hard for heavy carbide tooling removal of metal but still i use a similar method but always check with a DTI afterwards

[@TomsTechniques]

I used to check with an indicator, but never found it far enough off to matter. As long as you torque the bolts down evenly, nothing should shift.

[@TomsTechniques]

Wow, the pressure is on!

[@museves]

good god, this is awesome! any quick trick for those vise?

[@TomsTechniques]

Now that you mention it, I do have a video on how to indicate your vise in just one pass. Tom

[@nilamotk]

just made one, thanks for the video.

[@TomsTechniques]

You bet

[@gomezpiro]

Very good idea !

[@derernsti]

I use a live center with a morse cone from my lathe.. Its the same cone as it is in my milling mashine so it fits in there. Center the rotary table with the center and tighten the screws..

[@TomsTechniques]

Have you ever checked it with an indicator to see how well it aligns? You are relying on the chamfer being concentric with the bore and since it's probably 45º, it's not going to match your 60º center. Better check before doing anything critical. Tom

[@derernsti]

Toms Techniques Thanks for answer! Well... it was good enough for the parts i made so far.. They were pretty center ;-) Anyway.. Love to watch ur videos!! Keep going Buddy.. Greets from Germany!!!

[@TomsTechniques]

Thanks. Greetings form Michigan!

[@ronhubbard4663]

Tom, can you show us how you determined you needed a 3 degree taper over 1 inch. Then show us how you cut that taper. Sorry, I'm just a beginner. Sure this sounds elemental. I don't have taper gauges and wouldn't know how to use them if I did. Thanks, Ron

[@TomsTechniques]

Hey Ron, The 3º taper was just a WAG. I needed just enough to center up in the hole without falling through. I cut the taper using the taper attachment on my lathe. Another way to turn it would be to offset the tailstock slightly and yet another way would be to turn it using the compound rest set at an angle. Taper turning on the lathe is one of the topics that I haven't got to yet for my videos, but they will be coming. It doesn't require any special tools to measure a taper like this. You just convert the angle to taper per inch and use a pair of outside mics and a ruler to measure the diameters a known distance apart. Tom

[@matsworld9386]

brilliant, thank you!

[@severancetractor]

That's an awesome idea

[@TomsTechniques]

Thanks

[@hakimmic]

Nice Tip. Thanks. George

[@TomsTechniques]

Thanks George.

[@marko99butter]

I made one. Great idea.

[@sanjaysami4315]

Fantastic !

[@catherineharris4746]

Fkng outstanding! 👍👍👍

[@sidlinger]

Very nice!

[@ripvansparky]

Brilliant!

[@tedh.8356]

This is a good technique, even the half a thousandth that you may be out so what! how many home or even professional milled parts require a tolerance of better than +/- .001, most can tolerate +/- .002-.003! good time saving idea

[@glennedward2201]

Ted H. Most professional parts in my industry or more like .015 and that’s no joke. You want more accuracy you’ll pay and guess what? It just doesn’t matter for what the parts are used for nobody will ever know it could be .050 off. As machinists we cringe but consumers haven’t a clue.

[@kobe12345456780]

Thank you so much!

[@NaluKnives]

Very cool idea! Would you be willing to build and sell me one of those Tom? I'm a total noob when it comes to using my mill and this would be a huge help centering my rotary table :)

[@TomsTechniques]

The best way to improve your noob status is to make things. There are lots of project tutorials on my website that I made just for guys like you. Check it out: tomstechniques.com

[@CMAenergy]

Yep I'll make one of those asap

[@gabrielhernandez343]

great thanks Tom.

[@TomsTechniques]

+gabriel hernandez Thanks for watching

[@jpwipeout99]

I love it!

[@Stephen1455]

You realize with the indicator set like that you get a cosine error right? Where it is no longer 1 to 1 ratio?

[@TomsTechniques]

Dial test indicators are best suited for comparing features, not measuring them. In this case I'm comparing one side of the hole to the other, so cosine error doesn't come into play. For actual measuring, a dial indicator is a better option, or using the DTI to compare a reading to a standard, such as a stack of gauge blocks. Tom

[@TomsTechniques]

You are welcome.

[@navaho5430]

Top tip cheers.