Old Machinists Mill Trick To Quickly Find a Rod Centerline

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Note:
There are many ways to find a center line, and I'm familiar with probably most of them. I own several edge finders, along with many other location devices, that I have used probably more than a thousand times in my 30 years of machining. What I show in the video is by no means the go-to method of finding a center, nor do I express that in the video. It is only meant to give you a quick approximation of center.
I show you a technique to quickly find the center line of a piece of round stock in the mill. This was shown to me by an old time machinist many years ago, and it has been a tool I've been using ever since. Of course there are other ways to find center of round stock. I'm familiar with the other methods as well. This is just one of many.
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[@abcaabca6364]

This trick is great. Uses a flex scale as a tangent indicator. We tested a bunch of years ago with a bunch of people and they all easily saw a 1/2 deg off of 90deg. So would guess, even easier for level. 1/2 deg on a 2 inch dia rod is only 0.008 inch off. Sure beats eyeballing center. I snapped a couple of bits that way. I also liked him showing the dail gage method.

[@TinkeringNerd]

I usually keep the back lip edge of the vise as my y-axis zero. Then, I can just measure the diameter of a rod and move the table half the distance. Works every time! Cheers!

[@jeremysmith1339]

That's what I do...I always try to reset it to zero when done knowing the next time I'm ready to roll when I go to the machine..

[@nate12281]

thickness of the back jaw plus half the rod then set 0

[@13anomalous16]

Wonder what's the best way if you're working with an A axis and don't have a probe, edge finders in class will work fine up to a certain diameter. Maybe a long machinists square?

[@TinkeringNerd]

13Anomalous don’t A-axis’ have “home” position?

[@truanglo2170]

Tinkering Nerd, this is what a real machinist would always do.

[@davidt8438]

I’m a woodworker and have been using this method for over 20 years on my drill press when I have to drill wooden dowels. It works easily with large diameter dowels (or metal pipe/rods) but a little more time is required for smaller diameter pieces. Great job explaining to everyone.

[@bdf2718]

Nice, quick and easy. Very useful trick. Some people here, it seems, do not understand engineering. They do not understand the idea of "successive approximation." They do not understand that doing it this way first saves a lot of time and fiddling by getting a quick approximation then refining it. Others appear to have more money than sense and don't appreciate that some people can't afford the latest, greatest, *most expensive* kit. Some people, eh?

[@ArnoldsDesign]

Thank you. Well said.

[@highstreetkillers4377]

approximate isn't something a machinist ever says. Depending on the GD&T of the drawing doing it like this will result in scrap! Tolerance is the word a machinist says when something doesn't have to be perfect

[@highstreetkillers4377]

oh and engineers aren't machinists. they got no clue

[@kirbylee57]

Any particular reason or need you have for wanting people to know what you think about some people?

[@BrianB.-lb8du]

@@highstreetkillers4377 ...How fucking perceptive of you that engineers aren't machinists! Here's another dandy from the this troll... "they got no clue." Grade 7 English and grammar hard on you?

[@brianbender7438]

Very nice video! No obnoxious, loud music, clear shots and good description of a technique I can surely use. This is how to make an instructional video. Thanks.

[@fred463]

Thanks for the new trick. I am almost 67 and I try to learn every day.

[@eugeneanderson7984]

Thank you young man In today’s world it’s refreshing to see young men interested in work.

[@trackie1957]

Used this trick for years to set the lathe tool height, never tried it for this! One idea I had while watching you trying to level the scale by eye - if you view from slightly lower, you can sight the scale parallel to the vise body. Amazing how close you can get with this. For putting in set screws and such, way close enough!

[@Ur_local_planeLover]

Also can be used when setting lathe tool centres.

[@davidelliott5843]

Grind the teeth off an old hacksaw blade to make lathe tool shims and center finder scales/rules.

[@MW-yh9tm]

That’s the way I’ve always set my lathe tool just below center.

[@adam9674]

This is the way I was taught in school nearly 15 years ago, find the vertical then drop the toolholder a quarter of a turn under centreline, thought it was basic stuff. Thread-cutting on the other hand is a nightmare for me.

[@AtimatikArmy]

@@adam9674 oh shit, basic lathe question: cutting tool should be just below centerline and not AT centerline??? oh man guess I've been adjusting my tool holders wrong!

[@normcameron2316]

Yes, learned that almost 50 years ago in high school. Simplest is most frequently best. To come within .001" by eyeball with a scale [ruler] in this manner is not unusual. Plenty good for cutting an ordinary key way for a pulley or such, especially considering a rolled shaft such as displayed is lucky to be round to a thou. Great little video! Jogged my memory.

[@moeshipley4170]

I've been using this method for years, and it's an extremely accurate method for finding the center of the workpiece. I prefer to use a center drill in a collet to reduce runout to the absolute minimum; drill chucks (mine anyway!) usually won't center the drill as accurately as will the collet. On a slightly related note, if you find yourself having to drill a hole on the outside of a curved surface, and all you have is your trusty drill press, one of the best ways to avoid drill skate when starting the hole, is to take your favorite center punch and grind its point into three facets. The resulting "three-sided dimple" will center your drill bit beautifully every time. Excellent video!

[@ArnoldsDesign]

Thank you!

[@michaelhale4041]

I have seen this done on a lathe but never gave a thought to do it on a mill. Thank you for opening my eyes wider.

[@ArnoldsDesign]

Glad you liked it.

[@ardentelford2111]

I worked for almost 50 years in a machine shop and hadn't seen this exact technique, but did find it interesting. I find it a little bothersome that so many dismiss it for their method. I learned a long time ago that whatever works for you is generally the best. One size doesn't fit all. I also learned to listen to beginners ideas since some time they look at things in a simple view and ask why don't you do it this other way. Many times I asked myself, yeah why don't I.

[@machinemaker2248]

I never met a machinist with such a good attitude. The guys in my shop already knew everything there was to know.

[@anthonyedwards4423]

One more memory from an old machinist. Years ago my son and I were doing a line boring job at a power plant. Needed a 3/8" hole drilled centerline in a boring bar. Maintenance foreman told us to take it to their machine shop. Foreman there gave it to a machinist to do. It took him an hour to line up with tri square framing square six inch scale tape measure and all kind of eyeballing. Even a machinist level. We were told to stand against the wall and don't interfere. I bet my son that when we tried to put the two shafts together with a 3/8" bolt they probably wouldn't line up. We couldn't just run a drill bit through both shafts. The other was already drilled to line up on a power head so we had to use a carbide burr and grind out the hole drilled by the Union scale payed machinist. He never tried your method at all! Should have.

[@cwrobinson6363]

I will be damned! I am drilling holes like this in 7/8" wooden dowel rods. I am trying this out today. Thank you sir.

[@lowandslow3939]

I love old school techniques. For the type of work I do, that’s close enough. Thank you.

[@gorp27]

Fantastic idea. I am not a machinist but I do a lot of repair and custom work on small equipment and occasionally have to drill shafts to accept cotter pins. I hate that I have drilled holes off center and made a decent job look like trash, but now I know how to do it so that it looks good enough for the girls that I run with.

[@ArnoldsDesign]

Thanks!

[@LBCTITAN]

I was actually looking for a way to hold round stock when drilling through it and found this. Being a beginner machinist this will come in handy and I already have the 6" scale. Thank you!

[@asburgett]

Looks like a physical representation of a derivative in calculus.

[@okuno54]

It very much is! Or rather, the derivative is the way math describes this sorts of things. It'd be a good example in a calculus textbook, actually.

[@paulbuhler7874]

Slope at maximum is zero.

[@robertmcquarrie452]

Limits!

[@YourOldDog]

Home shopper here, great tip. Nothing I do requires accuracy greater than this tip will produce. I have used it on the lathe for finding center to set cutter but never gave it a thought how useful it would be on the mill. Thanks for taking the time to do the video.

[@ArnoldsDesign]

Thanks :)

[@normanreed572]

Same here. Was shone this as an apprentice 54 years ago and never thought of using it in the mill.

[@jakeparker3082]

This tip also works vertically on the lathe.

[@ArnoldsDesign]

I'll have to try that.

[@1995dresser]

Yes I still do it after 40yrs when I Single Point. as for a Mill buy an Edge Finder they are cheap or you can use a 1/4 dowel pin and a piece of Paper even cheaper

[@pieterbotes8938]

Toolmaker for 43 years. Old tricks like this is simple and does the trick

[@ArnoldsDesign]

Thanks!

[@hughezzell10000]

Well that's a nice little trick. I've just upped my game from eyeball to 6" scale. Next step, in about a decade or so, I'll make it to dial guage.

[@dwalrus7219]

Wow it ceases to amaze me how clever some people can be so simple so smart excellent video my mind is still boggling over what you just showed fantastic vid

[@forrestaddy9644]

I'm an old machinist and I can think of about a dozen ways to center the spindle axis on a diameter. The one you demonstrate was the second I learned as an apprentice in the early '60's. 0.002" TIR? Pretty good for an eyeball method but accuracy degrades as the diameter increases since the tilt of the scale is an arc sine function of the centering error. Another source of error is eccentricity of the point. Few drill chucks center better than 0.003" TIR and without a max error mark on the chuck body your error may vary unless you follow up with a tram. If you use a center drill, be sure to align the crest of the chisel tip parallel to the diameter centerline. If crosswise, the chisel tip constrains the scale's tilt to zero over the tip's width. Try it to prove it to yourself. You'll be expected to conduct this centering evolution in less than 10 seconds on the production floor and you'd better have the Indicol right handy to follow-up if you want to avoid a bellow from your boss. Plenty good enough for set screws, through pins, and most keyseats, though.

[@ArnoldsDesign]

Thanks for the comments. Good advice.

[@ryanfreeman125]

I don't know what was with the math gibberish. You didn't say anything that really made any sense. The reason this method is less effective with a larger diameter is because the contact point is wider. That's it. lol

[@ke6gwf]

@@ryanfreeman125, what you mean to say is, you don't understand the technical aspects of machining, or the mathematical functions that describe shapes and motions, and so anyone speaking science goes over your head, so you ridicule them to cover your lack of understanding? Got it.

[@steventhehistorian]

Forrest Addy, you made me realize how much of a hobbyist I am... It takes me a good 3 minutes to do this alignment and honestly I probably don't get closer than about 10 thousandths. Respect for your practiced speed, accuracy, and knowledge!

[@SuperMagicHyperDrive]

Thanks so much for posting this. My Grandad is a tool maker/designer and I've spent many years playing about with him in the garage, can't wait to show him this!

[@ArnoldsDesign]

Thanks for your comment!

[@btrswt35]

Cool idea. As a wood worker, I see it being plenty accurate for wood projects as is.

[@petertyrrell6690]

I am a home shop "machinist" and use this technique often. For most of what I do, no further accuracy checks are required. Thanks for sharing.

[@ArnoldsDesign]

Thanks for your comment

[@Rick_Cavallaro]

Excellent tip! Now if you can just remind me in 18 months when it comes up on a project.

[@jimanderson9403]

Great idea Man. Thank You for sharing. Old School Guys knew their stuff . That pre-modern technology era had very good imaginations . Reliance on the computer between your ears is equivalent to an Athlete going to the Gym . The brain is a muscle, exercise it and it gets stronger. Thanks again for sharing.

[@ponleduderacing2802]

I've been in the sales sides of cutting tools for over 20 years. That was one of my old go to techniques. It just works.

[@DonsWoodies]

Cool little trick Arnold. I am a retired Tool & Die maker, and it's obvious from your choice of words that you do this for a living. I have seen dozens upon dozens of 'tricks' to help out setting up a piece in lathes, mills, EDM, etc, but never saw that one. Love it. I won't be using it now since I'm retired, but it's still cool to see. Occasionally, I get calls from my old shop to help with something and next time I'm in there I will pass this on. I know a guy in the milling department who will love to add it to his bag of tricks. You did a good job explaining the process.

[@ArnoldsDesign]

Thank you. It's good to hear from someone in the trade. I've been stuck in machining/tool and die for 26 years now.

[@DonsWoodies]

You have my sympathies. LOL. It's a great life if you don't weaken.

[@normanreed572]

I worked in the trade for 37 years, retired, then bought my own machinery and still work. I’ve enjoyed every day of it. I still learn from vedios like this.

[@DonsWoodies]

Worked in tool and die for 43 years, owned a shop for the last 14 years, and retired last year. Still go in to the shop occasionally to grind or mill this or that and see the guys. I miss having 3 or 4 million dollars in equipment at my disposal by just walking out into the shop - now I have to drive 30 minutes Haha.. Still make Christmas presents for the office ladies every year from my latest hobby - woodworking. The thing that kept me interested in machining was, like this video, there is always something new to learn or improve on. Trained many people and every once in a while some new guy would tell me he wanted to be as good as me. My answer was always "No, son - I expect you to be better than me." Loved it when someone taught me a new twist on something I had been doing for years.

[@JCTXFF]

.001 that's pretty close for basically eyeballing it. Great tip.

[@michaelkarger7175]

But there is a huge difference between mm and inch! What unit is he using?

[@JCTXFF]

He said .001, and the old guys were that good. If someone is working within an inch that is blacksmith work.

[@kennethcaine3402]

Great video, very helpful I worked with some older machinists and they had so many time saving tricks of the trade, but I never saw them use this one. You are so right when you say you don't want to be almost center if you do you'll be an almost a machinist. Thanks for sharing this.

[@ArnoldsDesign]

Thank you for the compliment.

[@RRINTHESHOP]

Nice demo. also used on the lathe for tool height.

[@ArnoldsDesign]

Thanks!

[@scottb5515]

Yup. Do that all the time. 👍

[@staffordduecker665]

Yep... Do this all the time...

[@cyberslick18]

Its really only useful for a lathe, where finding correct tool height without taking a series of cuts and making adjustments can be more time consuming (although still extremely easy). I can't really think of a situation you'd find yourself in where you'd have a mill, have stock, having tooling, and not have a better, faster and significantly more accurate way of finding center. If you don't have access to an indicator or some form of measurement tool from the spindle, you wouldn't know if the vise was running parallel with the table movement, and finding centerline would be worthless anyway, unless you were drilling a single hole.

[@lorenzodicocco3748]

Awesome tip. Been doing this work my entire career. I have not seen this one. I will use this tip tomorrow at work. Can't wait to try it.

[@danielstewart3507]

That is an epic trick to use on a drill press.

[@finallyitsed2191]

An extremely valuable tip, very simply accomplished, but not something that I would have ever thought of in a million years. Thanks!

[@mywifeteresa]

For most work that is close enough, Great trick to save time.

[@ArnoldsDesign]

Thanks

[@BlackAdder1970]

I Mic the bar stock then edge find the solid jaw of the vise. Then move half way in between 😊 I have used that trick when I'm in a hurry doing lathe work to find center 👍 Nice tip!

[@ArnoldsDesign]

Thank you !

[@Xynudu]

Old as the hills. But works better than most "methods". I did a video on this back in 2016. Same principle as finding lathe centre.

[@cyberslick18]

What methods does this work better than lol? Other than eyeballing it with literally nothing else, this is the least accurate way of finding top dead center. Gage or dowel pin in the chuck / collet, sweeping with indicator, a $10 edge finder, zeroing the non moving jaw, all far more accurate and arguably faster.

[@ArnoldsDesign]

Thanks for your comments. Just saw it. :)

[@ianjarvis9638]

I can remember being shown this when I was an apprentice. Brings back memories. I also used this method to get a lathe tool pretty central.

[@williammoore3790]

In the trade for last 50 years first time I have seen this. Good idea!

[@lewisriesbeck8858]

Nice tip, for those of us that have a garage drill press and were not making parts for the space shuttle, it would work just fine. Keep doing what your doing my friend, we backyard mechanics can use this information, the pros already have there precise methods so they may not approve. Out here in realville, we apricate the help.

[@ArnoldsDesign]

You're welcome.

[@1pcfred]

I've heard about this other places. I've never seen someone check how close they were with an indicator before though. A thousandth is close enough for whatever I do.

[@mariedillon2900]

It's a clever way to find the center. Sometimes negative comments can be helpful criticism. Most machinist I know have thick skin. When close tolerances are required this method is not good enough. I've been machining for close to 40 years. Good video.

[@ArnoldsDesign]

Thank you. I have no intention of staying in a machine shop until retirement. I'd rather be beaten repeatedly with a club. I'm glad it worked out for you.

[@BIGWIGGLE223]

Wow. Lol!! That is definitely one of those Ah-Ha!!! tricks that is stupid simple and everyone should know it, but only masters know these little tips n tricks. Which is another lesson in respect your elders and when they talk you shut your trap and listen. Great little tip!!! Thank you!!!

[@ArnoldsDesign]

I'm glad you found it informative. Thanks!

[@richk3325]

This is really helpful especially for me who has a regular drillpress with no indicator gauge. Thanks, you're my fave scribe.

[@ArnoldsDesign]

Thanks!

[@jojomama4787]

I've used your method a number of times now,it works,I'm happy and I thank you,THANKS!!!

[@ArnoldsDesign]

You're welcome. Thanks for your comment.

[@ypaulbrown]

Arnold: this is great. I use this technique on lathes to center tools, but had not thought of doing this on the mill....Bravo....Paul in Florida

[@MakerCave]

Nice quick illustration of a relatively common method, that is no longer so common in the age of CNC production shops. Like others have commented, I have used this method for decades on the lathe, to get tool height correct, but for some reason, never transferred the procedure to the Mill/Drill. I always edge find, just to do it the "right" way. There are plenty of parts that I make in my home shop where "close enough" is just fine when drilling round stock on center. I will remember this one for sure when I need a quick center. Thanks!

[@lerch122]

what a supprise,i had better not forget that one

[@philipbreau1246]

Cool trick. I was taught how to centre (Canadian spelling) a tool bit on a lathe using the same technique. Use a steel rule between the tool bit and stock chucked up. When the rule was vertical, the bit was on centre. I never thought to use it to centre a spindle over round stock in a vice. Thanks for posting.

[@ArnoldsDesign]

Thanks 👍

[@tomliemohn624]

Interesting. I've used a similar technique for the lathe for decades, never adapted it to the mill like that! I've always used an edge finder. I like your use of a test indicator, THAT is something I will keep in my brain and likely use in the future.

[@deadchewie]

Bring the tool down to where it just touches the part, move the work back and forth . The scratch mark is center.

[@mohabatkhanmalak1161]

The scratch length on the round object should equal the dia of the mill tool, eyeball as close as you can bring them together and drill.

[@troyevans6355]

Same here.

[@ozwhistles]

Thanks! What I do is simply lower the quill gradually while passing the table back and forth, and just let the point make a scratch. Usually you can see the scratch form before it gets too wide, but you can eyeball the center of the scratch. I will certainly use this method too .. see how it shapes-up for less fiddle-time. One other thing I have noticed is that if you are using a twist-drill for the hole, it always walks-off to the left .. and you can estimate for that with experience.

[@x2malandy]

An old grey haired fart showed me this on a lathe when I was young. Used it my whole life. That old German guy showed me a lot of tricks.

[@MrJean9009]

You use this in lathe as well?

[@ernestocastellanos6446]

@@MrJean9009 to get toolrest the right height when turning/facing

[@internettoughguy]

Look like a great trick for a drill press too when close enough is good enough.

[@x2malandy]

@@MrJean9009 Yes sir. To set cutting tool on center or maybe a little above center.

[@MrJackandEmily]

I have been doing this on the lathe for a long time and never thought to do it on the mill.. Awesome, thanks mate! 😁

[@davidmastel5652]

Great trick...might try additionally make the scale parallel to the vertical vice and then use the far side of the horizontal plane of the vice to know when you are parallel and finding the highest tangent point of the radius even more repeatably. I thought is was a great trick and hopefully this might even make it a little better...thank you for sharing, we all learn from each other. I am blessed to be with an 84 year old active German visionary, innovator, machinist that has taken kindly to me... Very best regards... Dave

[@ArnoldsDesign]

Thanks for your comments Dave.

[@phyx1s]

Nice trick. You can also use a tiny/flat grindstone or flat milling bit in the running drill. Slowly go down approximately in the middle of the red. Where the stone/bit touch, it is exactly the middle. Grinding it more flat give you a nice starting point as well for the drill without having it slide off the top.

[@trackie1957]

I used this trick to set the tool height on my quick change toolpost on the lathe. Quick and it comes out spot on!

[@raptor0571]

I've been a machinist for 34 years haven't seen this until now. Pretty cool if you are using an old Bridgeport or drill press. Good old edgefinder is much faster. Good trick though.

[@ArnoldsDesign]

Thank you

[@whackycracker1987]

KZbin just keeps on recommending me really usefull stuff, thanks for the video!

[@rynohorn3819]

I remember using the scale trick for setting the tool height on the lathe. Never thought to use it on the mill. Very clever and thanks for sharing!

[@danielescobedo7968]

Yup used this on the Lathe all the time, German Machinist showed me this in 1978 when I started

[@joad47]

Thanks! For us "hobbyist" that trick will come in handy

[@Mimerneos]

That's so smart! It's like a visual lever for helping find the center

[@robertmccallum8626]

I like the idea as i use the same idea when resetting the table if you have put an angle on. What i do like is the drill chuck holder for the dial indicator never seen before. Inspired to make one.

[@kgee2111]

Been using this tip for years. It really works! Thanks for the video.

[@gregwarner3753]

A long time abo i repaired machinery and built prototypes. I used this method for finding centerline of a shaft. Another way to do that if there is a concentric hole through the stock like for drilling an oil hole in a bushing I would clamp the bushing in the vice then put a drill just slightly smaller than the Id of the bushing. Then extend the drill down past the end of the bushing. Set the cross slide so the light showing through the bushing was even on each side. Then raise the drill set the place along the bushing and drill the hole. If you have more than one bushing set up a stop. This is not exact but oil holes and set screws do not need to be exact. Save the time for exact placement for when it is needed.

[@jackbonanno8186]

Same technique works great on a lathe finding exact center of your cutting tool. Run your crossfeed in and touch the 6" rule with your cutting tool and does the same. Up or down until it's vertical.

[@murraypearson2359]

I use an analogous trick to set my lathe tools on centreline. Of course, there the scale is vertical instead of horizontal. Nice idea!

[@MrKidkiller159]

edge finder works fine for me ,inexpensive

[@jeremyk1366]

MrKidkiller159 damn right

[@ArnoldsDesign]

I can't use an edge finder on a large diameter part.

[@gomezpiro]

Arnold's Design , “ i set the paraller vise on cero with the edge finder before hold the piece “

[@salvadorebertolone]

Arnold's Design how are you holding a large part? Using 2 v blocks or 123/246 blocks, edge find the outside of the fixed jaw side, set as zero, move to the other and edge find and divide in half, move to that number and rezero no need to compensate for the edge finder as this is self compensating, this only works on a dro, if your mill doesnt have one, get one its too slow to use the screw scales, and you can make errors easier, it is virtually a necessity to have a x and y dro on a mill. Indicators are a last resort because they take too much time. Or get a haimer, they are so fast and accurate to use they pay for themselves quickly.

[@Iowahurler82]

You shouldn't need to get to the far edge if you can get the edge finder to the other side of the part with the quill locked. This way, you are on the same vertical line and should be at the same angle off of the center line.

[@goranandersson1073]

Great method! I have done a mathematical analysis of this and found the amazing accuracy of your eyes. The result is in a table below. The interpretation is as follows, if for instance the scale deviates 0,27 degrees from the horisontal plane, the relative error from the center line is +/- 0,30% (table lookup) . For a 10 mm rod that translates into 10*0,3/100, which equals +/- 0,03 mm. You report an absolute error of approx +/- 0,001 mm. The diameter of the rod you are using is unknown, but I estimate it to be approx 25 mm. Now let's reverse the previous arithmetic's in order to find the relative error and the associated angle. The relative error is then: 0,001*100/25 = 0,004 %. For very small angles there exists a linear relation between angle and relative error, so in your case the angle must be 0,004 degrees! Is really possible to perform an "eye ball" estimation with that accuracy? I think some lucky circumstances are involved in the example, but despite this it is a great method. Regards, Göran Andersson Angle Relative error (Degrees) (%) 0,000 0,000 0,009 0,010 0,018 0,020 0,027 0,030 0,036 0,040 0,045 0,050 0,054 0,060 0,063 0,070 0,072 0,080 0,081 0,090 0,090 0,100 0,099 0,110 0,108 0,120 0,117 0,130 0,126 0,140 0,135 0,150 0,144 0,160 0,153 0,170 0,162 0,180 0,171 0,190 0,180 0,200 0,189 0,210 0,198 0,220 0,207 0,230 0,216 0,240 0,225 0,250 0,234 0,260 0,243 0,270 0,252 0,280 0,261 0,290 0,270 0,300 0,279 0,310 0,288 0,320 0,297 0,330 0,306 0,340 0,315 0,350 0,324 0,360 0,333 0,370 0,342 0,380 0,351 0,390 0,360 0,400 0,369 0,410 0,378 0,420 0,387 0,430 0,396 0,440 0,405 0,450 0,414 0,460 0,423 0,470 0,432 0,480 0,441 0,490 0,450 0,500 0,459 0,510 0,468 0,520 0,477 0,530 0,486 0,540 0,495 0,550 0,504 0,560 0,513 0,570 0,522 0,580 0,531 0,590 0,540 0,600 0,549 0,610 0,558 0,620 0,567 0,630 0,576 0,640 0,585 0,650 0,594 0,660 0,603 0,670 0,612 0,680 0,621 0,690 0,630 0,700 0,639 0,710 0,648 0,720 0,657 0,730 0,666 0,740 0,675 0,750 0,684 0,760 0,693 0,770 0,702 0,780 0,711 0,790 0,720 0,800

[@beardtrick]

What RPM do you run that clock at?

[@ArnoldsDesign]

I have the second hand setup to run at 1 rpm

[@barry7608]

Simple and quick especially for most hobby work. Thanks.

woow man this was outstanding. Thanks a lot you just saved me. Thanks again.

[@jawadibrahim2367]

First time I've seen this trick was at Keith Fenner's channel, he used it to center lathe tools if I remember correctly.

[@Orange-Jumpsuit-Time]

I would suggest using a Spring Center Tap Guide in the spindle to eliminate having to fool around with quill movement. Also, see if you can incorporate on that scale, a mini Spirit Bubble leve with magnetic base, to eliminate squatting to level by eye.

[@erth2man]

I've often used a little trick similar this to pick up the center of round stock clamped in a machine vice. What I'll do is hold a flat file parallel to the vice surface and draw it down the length. It will produce a shinny thin line on the top that is a very reasonable center line. This is handy and quick to use in a drill press situation where complete accuracy isn't the order of the day.

[@ArnoldsDesign]

That's a good idea too. I'll try that.

[@richardberryhill718]

For my “hacking” work this is tremendous! Example: wanted to replace broken plastic screw handles so used aluminum rod and needed to find the center for handles (set 90 deg off), and getting anywhere near .005 to .010 was just fine, but had to figure it out trial and error. This is fine, too, for woodworking, which I do a lot of. Thanks!❤

[@roberthenderson760]

Was taught this at school 50 years ago , same for quick estimate of lathe tool centering , as old as the hills 😆

[@modelfabs]

Thanks for sharing. Its near enough for me No need for the DTI. You can use this method on the lathe to adjust tool tip and round bar.

[@EddieVBlueIsland]

This trick can also be used to center a tool (or go above or below) on a lathe documented in Republic Alloy Steels 1961 page 288.

[@123suzukisamurai]

Damn. So simple but brilliant. Thanks. Heck of a good idea

[@Abdu572]

Very smart way to find center line

[@richardhemmer1924]

Great tip for a part that you cant get a edge finder on!! To get you close before indicator of course. don't forget to incorporate backlash when creeping up on center!

[@daveat191]

Good tip and it also works well to set tool height on a lathe.

[@RustyorBroken]

An end mill spinning at a medium speed with a piece of paper makes a great edge finder. When the end mill grabs the paper your are .003 away.

[@ArnoldsDesign]

I also use that method. Touching off sides, or end of EM, and also touching off surface grinding.

[@chakathewolf]

Wow. 63 years old and I learned something new.

[@ilikefire0]

You can also use this on the lathe to center your OD cutter

[@johnparker2636]

Thats so simple - just brilliant -thanks

[@stevenmoomey2115]

Thanks for the tip, I bent the Axel on my Garden Cart, the new Axel isn’t drilled for the Hairpin clips. I don’t need it accurate enough to use a dial type gauge, but I would like to get it very close.

[@dhess140]

Good trick! This reminded me of something that I learn many years ago. Thanks!

[@curumo_curunir]

Thank you for sharing this useful method.

[@ArnoldsDesign]

You're welcome

[@theoriginalmungaman]

You can eye ball it with and end mill, if you’re cutting a key way then touch the end mill down and adjust till it makes an hour glass shape. Or use the end mill to touch the side and count in half the shaft plus half the end mill.

[@Stray03]

saw that on a .50 cal build video quite a few years back, It was close enough for what the guy was doing with it.

[@cowboysadventures3287]

Thanks for the tip. I’ve used that on a lathe but never on a mill.

[@redwood_shores]

This is truly brilliant. Ton of thanks for sharing!

[@nlabanok]

Very nice technique, clever ! Thanks.

[@johndonlan5956]

I've seen this done before..... I forgot about it until now. And yes, it was an old time machinist who taught it to me. When I was a machinist I just used an edge finder, or sometimes a test indicator...... Depending upon the application. This is a handy technique for finding the center line..... But I have to ask myself "why would I want to sacrifice precision, just for the sake of saving myself an extra 5 minutes to check things correctly and accurately?"