How to leveling a Lathe
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- Опубликовано: 19 июл 2019
- This is not your normal Lathe leveling video. I do a deep dive in measuring how the lathe bed twist and bends when it is being aligned. If you like technical data this video is for you. Don't worry if the tech stuff is not for you you will still get a lot out of this video.
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It is very important to adjust these machines accurately, I remember as a young apprentice having to use two lathes in the one place that had all these problems because they weren't set up and aligned and they broke my heart. Bear in mind too that the whole lathe does not need to be floor level, that's irrelevant. It could lie at a slope and work perfectly. The thing is that it has to be level flat and aligned within itself only, so if the level is off a small bit across the bed at one end and its off the same amount at other end your fine. And always as a previous viewer said always prove the spirit level by turning it exactly 180° to ensure its accurate and not telling lies, otherwise you'll be chasing your tail and going around in circles.
Your level/alignment description is pretty good. I suggest on a machine like you demonstrated on that you set up two levels 90 degree opposed on the top of cross slide. I always favored 2 Starrett
.0005"/foot levels. Don't move the levels. Move just the saddle. Check for linear level over the length of the bed with the level in Z direction. This will let you see bed dipping or crowning as you traverse in Z +/-. Pay attention at the same time to the level in X orientation. This will let you monitor bed twist simultaneously with bed level. Use the rear headstock leveling bolts primarily to control bedway crowning and dipping.
You refer to spindle alignment. I call this check testing for spindle taper. With weight on all leveling bolts and locked in place, you have confidence that the bed is level and stable.
I don't bother with the relief cut on the spindle test bar, simply turn the test bar with light load and good finish. This allows you to check turned taper over the length of the test bar. The taper error on an accurate machine will be consistent over the relative length of the test cut. No relief cut allows taper confirmation over the whole length of the test cut bar. Determining which way to move your headstock taper adjustment jack screws should be obvious if you observe the relative locations of the jacking point and the headstock pivot point.
Thanks for pointing out the necessity to monitor headstock movement when simply untorqueing the headstock hardware.
Monitoring the test bar for movement with indicators is extremely important, as the headstock will move by simply untorqueing the headstock hardware. Not monitoring it will give you no knowledge if it moved or how much. You will quickly start chasing your tail.
Document everything that you change and its effect. You will be surprised how confusing incorrect adjustment effects will compromise your corrective efforts. As a mechanic I owned and employed more indicators and mag bases than most machinists. Data is everything when you are "leveling" a machine tool.
Simple geometry/trig estimates will help predict how much you need to move to get required headstock taper correction. Your example showed that the inboard indicator was X delta from the pivot point and the outboard indicator was about 2X delta from the pivot point. This would require moving the out board indicator 2X the required correction. The second taper test cut will confirm your estimates. You encouraged turning off at least .002". Make certain that you turn off enough to ensure that you get test bar cleanup.
Depending on the machine use will determine if you settle for taper error large on the chuck end or tailstock end. If I couldn't get dead nuts .0000", I suggest settling for larger on the chuck end. Part deflection under general machining is most likely to contribute to larger tailstock end part taper.
I have watched machinists use an inspection grade round test bar in the lathe spindle chuck and indicate the length of the test bar from the tool post. This test only confirms the machine integrity. This test cannot tell you the source of error. Levels and turning headstock taper are the primary sources to document the cause of error.
I think that there is no reason to periodically test for level, crowning, twist or taper error unless you cannot control part integrity. If you turn good parts, checking for level, twist, crowning, and taper is superfluous.
By the way, level on a lathe is overrated. Level accuracy is relative. If coolant drains where you want it, who cares if the machine is level? Twist and crowning is important. CNC lathes are built on an out of level taper of nominally 30 degrees to enhance chip and coolant removal. Typically we just bolt a non precision leveling plate to the turret face. Using modeling clay under the level to zero the level bubble allows all the previously described level, twist and crowning tests.
I did machine set up and maintenance for over 34 years. I can recall almost never needing to actually bolt a machine to the floor to control the issues under discussion. Bench top machines lack relative weight and mass to control rigidity. Hobby guys may consider bolting down light duty machines. If you are really concerned about machine level integrity, ensure that you don't straddle concrete floor expansion seams.
@Paul Hunt Thanks for taking the time to explain all this! The reason I read the comments sections is in hopes of coming across helpful & informative comments like yours.
Thank you for taking the time to share your knowledge. I've often wondered why on occasion RUclips will send videos on topics the viewer may know inside out. Perhaps the reason is to spread the knowledge as you clearly have done. Nah, it just gets lucky on occasion.
Excellent explanation - Thank you Paul
Hey Dale, that was a very thorough demo. Good job. Thanks for the mention and the link.
Nice work Dale, always like to see how machines are tweaked as it often helps me with other applications.
Build Something Cool.
I'm a retired construction surveyor. The one thing I didn't see was the calibration of the leveling bubble prior to any other levelling work ? That is the 1st thing that needs to be done prior to any other level checking. The calibration is easy to check, a magnifying glass would allow more accurate checking. Put the level in a convenient flat surface & mark the end points with a sharpie or similar pen & that is said to be face 1. Then observe the position of the bubble. Lets say it is exactly showing level. Then just lift & rotate the level 180 degrees placing it again on the 2 pen marks, this is face 2. If the level is correctly calibrated the bubble will again show exactly level. If it is not then there should be an adjusting screw(s) on the level to move the bubble a very small amount. This amount is 1/2 of the total variance between face 1 & 2. It's a form of iteration, as in keep halving a number & you get near enough to zero.
Lets just use this as an example. Position 1 the bubble shows level. Position 2 the bubble shows 1/2 mm variance. Then the adjustment is made at 1/4 of mm. Rechecking the level on face 1 & face 2 the variance should be 1/4 mm off the centre bubble. This then means that the surface used to measure level is 1/4 mm out of level.
In surveying there are precise level tripod mounted units used for some procedures. Like in tunneling where marked points are checked from time to time to see if rock movement may indicate a possible collapse ? These levels are graduated to read in 1/100 of a mm or similar in inches. These levels are sometimes used in levelling workshop machines. 1/100 mm far exceeds what those machine levels can do. Leveling is related to the centre of the Earth just like all level bubbles & plumb bobs do.
Precise leveling is the best way to level these machines. They can tell you how much you need to turn a leveling nut once you know the thread spec. It's a lot faster & more accurate than any other means. This is because all relevant points can be checked & rechecked accurately & quickly. The main problem is that most machinist orientated people don't know about this precise levelling option. I believe they can be hired from SOME companies but not everywhere. Even automatic builders levels can give very high accuracy as well because the instrument is not far from the machine. An auto builders level with magnification it has for this work (x22 - x30 depending on the model) can split the black marked lines on a machinist rule. That's probably more accurate than most machinists levels ?
Great info, Dale. Thank you. I am planning to upgrade from a South Bend to an American TW 3-phase, and this will come in very handy.
I’ve been waiting for this one. Thanks Dale!
Great video Dale, a lot of great information and method.
Wish I could hit the like button more than once. As always, good job Dale.
I love the use of the plumb bob to level the bed since I done have a machinist level. I then put a cheap pencil laser in the chuck and ran at high speed and taped a white piece of paper on the tail stock. I then tweaked the head and bed ways to get the laser on center at the tail stock at maximum length and it stayed on next to the chuck. My test cuts at both ends were within 1 1/2 thou over about 30 inches.you can adjust the alignment with the chuck running . Maybe i was just lucky?
Thanks for the video dale! met you at bar-z summer bash this past June, what a fun event it was. This will come in handy when i set up my new to me lathe
Very nice explanation. You speak clearly and constant with a Understandable English even for me from Brazil. 😊
Nice Clover. I got a Cincinnati, 7 foot. Thanks. Your words are marvelous!
Thanks Dale, you are so smart but you can explain it in such a way that I can almost keep up.
I've got one of those Polish levels. Got it when I was installing CNCs. Works great but kind of slow to settle. My lathe sits across a joint in the concrete floor. Not a good idea, but that's where it fit. After 6 years I decided to see if it was still well set up. It took a very slight turn of the leveling bolts to bring it back. Using a commercial MT3 test bar & test indicator, the tailstock was in alignment with the ways. Using a 2" bar of steel, the head stock still checked true to the ways. I had previously aligned the head stock. I put centers in a 1" bar of steel and pressed two rings of metal onto it so I could use it to check the tailstock for offset. I chased my tail until giving up @ about .0002" in 10". Good enough for mostly hobby work. About 4 hours including making the rings and pressing them on.
What happened to this channel?
Great content, thanks, look forward to watching more of your channel..
Excellent video. Thanks.
Your explanation is crazy clear that even a not mother tongue like me could understand everything:9) thank you so much for ur professional sharing!
Cool video.... I remember when I was in high school in 1994 we went to Half Moon Bay with the our high school band.... good times
Nice video Dale
Perfect timing... my lathe just arrived the other day!
Nice job Dale!
Steve
Enjoyed Dale!
ATB, Robin
Metrology, something that gives you a pain in both ends! Love the wall mount for the camera.
That's a cool indicator you've got!
I like the way you have that camera mounted on the wall. I'm doing a camera upgrade. I might have to do something like that.
Nice demo.
Hey Dale, thanks for an excellent and informative video. Regards MachineNZ
Thanks. This is a great resource.
Very helpful - can you share a link to those precision ground flat stones that you like?
Thank you very much for the information.
Grande: sei bravissimo e mi piacciono i tuoi video, purtroppo non capisco la tua lingua ma riesco a intuire quello che fai dalle immagini. Il tuo sorriso sempre presente è bellissimo. Ciao
Thanks loved the video does that apply to all Metal lathe big and small as I am building a new stand for my little hobby lathe with in reason of course thank you
Great video. Thanks!
Great job!
What brand of precision ground stones do you have? Link?
Thanks D!
I have one of those .0005/12” clones. Indeed it will drive you crazy. Being able to measure to a point you cannot machine to or correct is tempting but maddening. Tried the plumb bob trick once for kicks and it didn’t work. To much location error when moving it from one end to the other. I like the way you did it here with the level on the carriage. The plumb bob might work like that measuring to some consistent line. Great stuff!
Great information
great video dale,, As someone that working in the surveying world I would you check the level its self by reversing it in the same position and checking the bubble returns to the some spot . just my Five cents worth.:-) I use a 0.02mm/m bubble to check some equipment and I agree its a pain.
Dale, can I ask what chuck that is in the beginning of the video? It looks to have a built-in cam centering system that I've seen on a few chucks, but never managed to track down to a brand or a ''name'' for that style of chuck adjustment. I believe Dan Gelbart's adjustable chuck he shows in his workshop tour uses the same concept, but he built that himself, wheras this is a factory job.
Thank you for the vid, great one!
Great video 👍🏻
You always seem to find the best deals on gear!
Thanks for the tips Dale. I now have 2 Taiwanese lathe’s that the headstock can adjust, my southbend and Clausing does not. I really don’t know which is better. Thanks for the video. JB San Diego
Another great informative clip, how often would you recommend checking the set up I assume it may change over time?
I'd go with 6 months on not much run. Every hour for hard production.
Nice video Dale, thank's! I'm not trying to be a smart ass or something here but I was wondering if you checked your levels before you started out?
Thanks again.
Awesome brother I just did the same plumb bub trick on my south bend model C I made a video of it and it came out 100% staying on 0!!!!
You're giving me a very Harrison Ford kinda vibe. Fantastic video
Really Good Video.
Merli is a great , has been because nowadays are out of businees, lathes manifacturer. enjoy his quality
Great video. I have a small lathe (German brand but actually Chinese). Other than the Tail Stock horizontal adjustment there are no adjustments. Does this mean that levelling and bed twist are not a worry or that the lathe is just poor quality?
Any comments or suggestions welcome...
My lathe has 14 leveling points! I am dreading leveling it.
They must have had a procedure to simplify it.
And knowing what kind of iron you prefer I'll bet each leveling foot is 200+ lbs and requires a 4' cheater to adjust it!!!!😁
Is there any practical way to scrape a machine without having a professional straight edge of any sort? I have a very old mill the knee moves up n down very easily on the upper part of its range, but the lower is rather hard (minimal wear there I assume) I would like to spend some time with this machine in the future trying to fix it up a lil bit (no intention of making it perfect to the 1/2 thou) its never going to be as nice as a modern Bridgeport, but would just like to make it a lil better. Any thoughts?
Excellento!
Thanks for showing. I came to the conclusion if you have a bench lathe, bolt it down, you going to bend it unless the surface is 100% accurately flat or leess flimsy than the bed, then you have to understand this and shim it.
At 8:42 I think you meant to say 9 tenths of a thousandths. Don't feel bad I hear Keith Rucker say X ten thousands (X times 0.01) when he means X tenths of a thousandths (X times 0.0001) . BTW Keith Isn't the only one, you're in good company. So don't sweat the small stuff, and it's all small stuff. Love the vids, would like more!
Thanks!
Darn....didn't notice the mug, but i did notice the can of human coolant in your lathe pan ;)
awesome! Danke
Pretty Good ❤❤❤ from Newzealand 🇳🇿🇳🇿🇳🇿🇮🇳🇮🇳🇮🇳
Thanks
The place I work is proposing to put a 3 foot extenton on the bed of a HAAS TL1, to chamfer Hot roll tubing 6 foot long, 5.5" diameter .25 wall. Has anyone ever done such a thing? I can't even see how the tiny tailstock can hold the other end.
Hi, Thanks for your excellent video. I am about to purchase an engineers level. The temptation is to purchase the highest accuracy, resolution or sensitivity device (used interchanceably in adverts but all having different meanings in metrology) so I heed your warning. Your video suggests the Starret 98 is ideal, my question is what sensitivity/accuracy/resolution is yours, you said accurate to .001/ft per division whereas the Starret website says each division is .005/ft. Sorry about this trivia but in the UK Starret are not cheap so I need to make the correct choice. I also apologise for what may be seen as nit-picking an excellent practical video.
it's 0.0005 inches per foot
The Starret 98 is .005" per foot. The 199 is .0005" per foot. s3-us-west-2.amazonaws.com/catsy.833/Catalog+33+Section+18+-+Machinists+Levels.pdf
Hi, why don't you use two indicators when adjusting the headstock just like you show with the cardboard. So just adjust the difference on the indicators to be the same as difference in radius. Might work with just one adjustment. Kind regards Mattias
Why do you say that the higher precision level will drive you crazy? Does the sensitivity make for a more difficult user experience?
You really mind f’ed me there bud. So if 10 of “ those” = a thousandth of an inch.... Those would have to be tenthousandth marks. But we know the “thenth” (tenthousandth) is is only 4 decimal places. You’ve got 5 ( I can’t really see the indicator clearly enough to confirm where your decimal place is on your indicator...) but if it measures in .00005
It would be reading half thenths orrrrrr... saying in the terms of millionths. It would be the equivalent of (50) millionths stacked up to equal one of your marks on that graduation scale.. k I’m sorry I have no clue. Let me know what you think lol. Btw. Love your video. This knowledge is gold my friend. Thank you
Like it.
The worst thing about your level cooking down is the bubble will progressively shrink but if it kept warming up it would expand. Still Its not a bad idea to let the temperature settle somewhere.
Was hoping to see lasers and plumbobs again lol
Check your Starrett 98, it clearly says 0.005" per foot on it, not 0.001".
According to Starrett's website the 98 series levels have graduations that are equal to .005 per foot.www.starrett.com/metrology/product-detail/98-12
No shame in getting tangled up over all those places after the decimal point. I sell tools and when it comes to reamers, I always have to slow the interaction down for my customers' sake and my own so that everyone is on the same page and we get the correct size out to that 4th decimal place.
👍👍👍
WHAT,,,,,,,, this is all bloody wrong, you never even used a folded beer mat!!!!
Awww - no mugs left? Me wanted one :).
Crack or tweak?
Kind comment .👍👍👍
haha
Say something nice. Ok. Here ya go.
Keep the beard. It looks great on you...
Also keep the videos coming. I enjoy them all and most of the time learn something too.
YOU STILL LIVE IN SF.
Никуя не понял, но очень круто! ))
The lathe looks very similar to a meuser
Can anyone explain why people say it is millionths, when it's not?
Hey Dale, thanks for taking the time to output another video. I can't understand your anxiety with the 'kind comments' though. Please spend some time so that the information you put up there for others to learn off is correct and kind comments will come flowing! I am not the most experienced machinist in the world but I think you had a sloppy approach to the matter, from the description of the indicator (what does '...about at thou...' mean?? ) to the two-collar method. You have the potential, just plan your work a bit more.
In any case, thanks for the effort you put already.
Jo Pi and ToTony are cool, for sure, but you ain't seen nothin' till you see Dan Gelbart's lathe: ruclips.net/video/sFrVdoOhu1Q/видео.html
Wondering if that lathe came standard with a bud light can 😝
Probably not, water and machinery usually equals rust.
Even if it doesn't, the magic of the home machine shop is that the beers just appear somehow.
@@kieronscully1161 My unanswered question is if beer is a coolant or lubricant. I have found that a cold one on a hot day helps take the heat away, then again, after a hard day a cold one helps lube the gears in my head so I can relax some.
You think half a thou will drive you nuts lol I have 2 levels I use on cmc machines 20um per meter and 10um per meter. The latter of the 2 will drive you nuts
Italian lathe uh?
Lol, bud light😅.
I saw that. He panned past it very quickly didn’t he?
"How to leveling a Lathe" - speka da englis?
Do you think that someone understood something of what you told us so quickly?
I learned a ton from the video.
Good explanation. You can get chapter and verse from Connelly's "Machine Tool Reconditioning", which is available entirely legally as a pdf from the internet archive.
That said, your pronunciation makes my skin crawl. Height is "H-ai-t", not "h-ai-th", temperature is "tem-pur-a-chure" or "tem-pra-chur" not "tem-pi-chur". Eeeagh.
Depends on where you live, and what you are used to. I could clearly understand and that's what it is about. No you can correct my english if you like.
Would enjoy the whole video but after 5 min that rustle from your mic is to much to bare....terrible mate, you should know better
1st
just get to the point. man you love to hear yourself talk.
If you want that kind of precision from a lathe, you're looking for the wrong machine tool. Get yourself a Reishauer grinder or SIP Hydropic 6 and be done with it FFS
Stop talking shit