Leveling the American Pacemaker Lathe
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- Опубликовано: 15 сен 2024
- I'll get the American Pacemaker lathe leveled using the precision levels, eliminated twist in the bed and setting evenly on all 12 leveling pads.
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Watching Adam spend an enormous amount of time to get the lathe exactly “right” reminds me of “The Bob Newhart Theory of Accounting”.
When Bob was a young accountant, he thought that “hey, if the trial balance is within $3 or $4 bucks, it’s close enough “ which led to, as Bob described, “a varied and interesting number of different careers in the industry”!
I wish he would high lite leveling the lathe instead of watching him trying to move lathe 16th of a bubble. Or get some to help to save some time for all of us. Im checking out.
I love how Adam is so precise and meticulous whith every project he does , and in the end of it his smile is priceless when mission is accomplished 👌👌 thats a real Master right there
He’s the most fastidious person on RUclips in my opinion.
yeah this smile was coming from the deep of his heart
Hello Adam, I have been watching your videos for a few months now, and have gone back to the beginning of your channel and am watching all of your videos in order, while also watching the new ones as they come out. It's cool to see how far you have come. I am currently rebuilding my dad's old shop and your videos help keep me motivated. It was nearly destroyed in a tornado 2 years ago and I have a long way to go, but every little bit of work gets me closer. God bless.
To everyone asking about levelling lengthwise (parallel to the ways) to eliminate hogging or sagging in the middle... yes it is important but one checks that AFTER levelling crosswise. First thing is tho get the twist out THEN get sag/hog out. THEN check for headstock alignment. Headstock alignment requires that you have something straight to align it to! Easiest way to get the bed straight is to use a precision level. There will be follow ups after the lathe has had some use and settled. *Everything* bends and twists... even a reinforced concrete floor. The question is by how much? and how much it varies over time and use. If you can measure by how much and it is enough affect the accuracy of the work then you can do something about it.
I'm thinking of giving my lathe a slight lean to the tail stock end, for the coolant to drain to.
@@jemijona The problem with that strategy is changing the level so that it actually helps drainage (or even makes it possible) by any noticeable amount is that it will also bury the bubble of a precision level on the uphill end. I suppose you could make some sort of base for your level to sit on with a few degrees of taper.... then you could get the drainage you want and still make sure your ways do not have any lengthwise bend in them. Might be easier to just alter the level of your coolant pan.
@@utidjian I wouldn't need a precision level for head to tail stock. But as long as their isn't any twist in the ways, I believe I should be good to go. I will have a good think about this when I do level the lathe. You would freak if you saw my lathe right now. It has yet to be set up and it has around 40mm of packers under the headstock and none under the tail stock. It took a bit of work to lift the headstock to get some kind of lifting device under it. I am doing small non important jobs as it is at the moment, but once I get my shed extended, then the proper setup will happen.
Very precise levelling of a machine tool, respect Adam thanks for sharing.
I saw "American Pacemaker" and it brought back great memories! I started as an apprentice in 1972 working for Eastman Kodak in Rochester NY, and I ran one of these for quite a while and LOVED IT! WoooHooo! It was an "old-timer" in '72 because it had "War production board" stenciled on it! but it ran like new. Very heavy duty machine and powerful, easy to change speeds, a real PEACH! Good luck with it Adam! JW
thankyou so much Adam. It would have made the whole process more tedious for you but I feel the effort you went to in filming the indicators really gave us the box seat in terms of understanding what goes into a critical undertaking like levelling a machine which relies on precision.
your RUclips game is something you can be proud of...
👍👍👍
*Another* superb video. A joy watching somebody work who knows what they're doing. No BS, just solid information and great delivery. Thanks.
I have had the same problem when levelling machinery, large or small, but especially large machines of keeping an eye on the levels as I make adjustments. We ain't teenagers any more and a couple of hours doing squat-thrusts gets pretty tiring. What I did was mount a webcam looking at the level(s) and monitor the adjustments AS I was making them with a laptop on the floor beside me. Even easier now with a wireless monitoring app on your phone or tablet and a gopro or whatever looking at the levels.
With the camera-wifi/bluetooth-phone/tablet/laptop method you can level a machine of just about any size. Conceivably you could level a lathe on the top floor of the Empire State building from the jacking screws in the basement (if it has them)!
Good job Adam!
Me and two other guys were leveling a turntable for cars for the car show last week and I wish someone had thought of that! Strike that! That would be less work for us. :)
That's using your noodle, i couldn't walk properly for days when i leveled my big lathe.. I'll copy that idea when i move everything to my new shop.. i have a little 15 dollar endoscope now that plugs into my phone and it would be easy to stick in a indicator holder for easy aiming
I've never done more than a carpenter's torpedo level. Thanks for showing me how to do it the right way! Nice video.
I enjoyed these two videos of preparing this lathe for work. Thanks for letting us look over your shoulder.
I have done this task too, and my method was to snug down all the jacking bolts by hand and then pre-load all the bolts by 1 1/2 turns.
That way the machine had all the bolts with roughly the same amount of load.
Then if I needed to adjust one end I would rotate all 4 bolts equally. This kept the load evenly distributed around all 4 bolts.
If I needed to adjust across the machine I would do 2 bolts/side at a time. Its not perfect but worked for me.
We also had a 199 and I used to hide it because the other guys mis-treated it...I don't think they understood just how high quality a level it was.
It's great to watch you keeping this very fine machine in excellent condition. It's good for many years to come. Well done!
Could the bed have a sag in the middle as you only supported it at the ends initially? I would like to see the level on the carriage the other way round and run from end to end. Des.
Agreed, but you'd only see a difference in long, very small diameter stock. I mean, imagine it drops by 5 thou on a 1" bar. Do the trig and the diameter change is negligible. Vs the twist has a noticeable effect.
If you got really fussy, you'd need to do it optically as the curvature of the earth is measurable at these levels of precision. At least according to my math it is.
Unless you had a decent load on it in the middle (which you shouldn't while leveling) I doubt there is any effect. This would be noticed anyway later for final.
I'd be curious so see how much variation there is. But given the that tool height is usually adjusted visually, I suspect keeping that dead on doesn't matter much. In theory a sag could bell or barrel a work piece, but what's the deflection on a shaft from tool pressure and how does that compare?
Yes, what about the lengthwise sag..?
Very good video,Adam.Congratulations and thank you.Also that reminds me that Robin Renzzeti and Stefan Gotteswinter found their own limits on precision or as someone said every time that a leaf in the tree moves,the whole universe moves (I. Newton and others.)
Interesting side note: the reason that granite started to be used for surface plates was materiel shortages during WW-II. The reason that people never went back (to cast iron) is that damage to a granite surface tends to not leave high spots, just voids, where as cast iron tend to form an elevated ring around any damage.
Really, I'd never thought about it in that way, i'd always assumed that iron is ok for small 30cmx30cm plates etc and being small the thermal distortion was negligible but with larger plates and 'tables' the thermal distortion and physical ridigity became a dominant factor. Of course it could also be (thinking about it some more) the developed ability to ultra precision grind granite surfaces, and be able to measure the flatness that prompted the practical abandonment of iron.
id add that granite is a far superior material for surface plates, it never rust, very easy to maintain, and easy to lap in to a nice flat surface. It doesn't have all the internal stresses of cast iron either. Plus it looks really nice all polished up!!
Treading down a path that is defined by your generations before you. Much respect!
One note on the precision stones, if you have three and lap them all against each other (A/B, B/C, A/C, repeat the cycle a few times), they will automatically create a precision flat surface. Just two could cause one to be convex and the other concave (mathematically, the surfaces would be a section of a sphere [both of the same radius], but that is assuming perfectly even lapping and even minor rotation of the stones)
Lol, that compound casting is so freaking HUGE!!! what a beast.
That really impresses me how little input it takes to make a difference in the twist. All the world is a spring. Even giant monster castings.
I like Robin Renzetti's comment - "At some scale, everything is rubber"
Adam..just wanted to say that i am super happy and excited for you man! It's awesome to see the development of this new space, and seeing these new and new to you machines. I'm a long time subscriber since back when you did your monster machining at your old job. Oh how far you have come my brother. Can't wait to see what else you are working on for the future!!!
The precision of a machinist come with a lot of patience.
You have to start with the machine level. As with any precision work, the term level or accurate is relative. The more accurate the more likely you will have good results, Yes, and I agree, settling does happen during operation, constant monitoring is something that should be part of maintaining and accurate result. Well done Adam, have a great week end.
Wow new shop is looking sharp
Can't wait to see her all cleaned up and ready to get back to work.
Crazy that something so substantial can twist
Not twisting by very much, however.
Time consuming yes, but the end result is worth all the time you put into it. Nice job, nice video. More proof of what made you the great machinist that you are.
Hi Adam,....... a superb job, very well and patiently done!. Looking forward to seeing progress from here!
Would it be worthwhile to Bluetooth to a repeater screen, camera to repeater, to see bubble movement on the repeater screen, as it happens, rather than going back to the bubble to see the movement? Time is money. The time and energy which could be saved has value. If Adam is letting us see movement, he could join us. This video was great for letting us see how a master takes every opportunity to put the best quality into the product delivered. Thank you Adam.
I was trying to not bump my desk even while watching that .lol ... Great precison. As with most things, a great end result is in the preparation.
Machining, it's an art as well as a trade.
Nice work and teaching method. When I was a young apprentice I was taught to work in a figure 8 while stoning. I always used this method for milling machine tables, vises, steel surface plates, and even cylinder heads/engine decks. Anywhere you required a nice flat surface. Have you or anyone else ever heard to use a figure 8 pattern?
Love the way thing are going to be right in order to make your job top notch. Beautiful work Adam
Hmm, could the lathe be bowed from front to back though? Like if the middle is lower than the ends. That's definitely something I'd check for as well.
Btw. for precision levels, at work we have some really fancy digital precision levels that measure to one micron per meter accurate. That's 12 millionths of an inch per foot. Crazy...
That sounds like it would almost be sensitive enough to be thrown off by gravitational irregularities in the surrounding area. Crazy.
Is there any way to set up an leveled laser beam on one end of the lathe and focus it on a level receiver on the far end. Between beam and the receiver near the center of the ways place another block with a tiny precision hole. When’s the beam is set exactly right it should go right through the tiny hole proving the center is the same height as the ends.
@@F0XD1E Especially when you consider that Adam does distort gravitational waves. Especially after lunch.
@@F0XD1E nah, that's a whole other magnitude of scale. but you can definitely see it move when someone is leaning on the machine bed.
I remember sending the apprentice to tool shed for bubble fluid. The good old days.
Was that before or after you got him to go to the paint shop for a can of striped paint, or to the store for a can of warm K9P? 70 yr old retired bloke who remembers those days as well.
Ha. At my brother's work, back in the day, a newby tech (a young woman therefore a fair target for The Guys) was sent to get something pointless in town. She went home, read a book (pre-internet, so decades ago), cooked a nice hot lunch, read more book, then made her way back to work by 3:30. The big boss was upset and wanted to know where she'd been all day - "So-and-so sent me out to pick up some whatever. I've been all over town but couldn't find any. Sorry So-and-so." What went around came around. She was a smart young woman!
@@bobhudson6659 I remember "the long weight" I went for forever.
Don't forget a can of compression and a packet of grinder sparks
My favorites was spray weld remover and rubber backhoe teeth.
Did not no it took that much to get it level thanks for sharing
Some nasty big cracks in the floor at the tailstock end. Hope they're stable, or you might be doing this routinely! Love your videos Abom!
That is a shame, isn't it. It's a nearly new slab, or at least less than a year old.
After seeing the work involved in leveling these machine's. That back in the day, there were probably business that did nothing else but travel around and level these machines.
Great job Adam, looking good around there, thanks for sharing with us. Fred.
Olá amigo Adam!!!
Muito bom aprender com seus conhecimentos!!!
Trabalho sempre ricos em detalhes!!!
Abraço
Watching this has me thinking about leveling my mini mill.
Tedious time consuming details sure do try your patience but it gives piece of mind. Thanks for letting us see how it should be done.
I didnt read too far down in the comments but, My Clausing 15x48 owners manual required use of the bed its self. using a parallel bar on each end to remove the twist, then across to get it level. Id be pressed to say after 60+ years in service the carriage and bed would have enough wear it the typical "work areas" would make them very poor surfaces for leveling or removing twist in relationship to the head and tail stock.
With so many feet on each side, I wouldn’t turn any one too much as you will get false readings as that area either drops or rises, warping the bed. So sure, turn a quarter to a half turn on one end, and then do each other until you reach the other end. Just keep doing that until you get approximately where you want. Large lathes are a pain to “level” because of so many feet. If you’re not careful, you can get the bed “leveled” through the length, only to find the bed humped up and down along the length. So no twist, but the bed isn’t straight either, it’s wavy. That can be hard to see. You have to put the master level lengthwise on the bed, and move it a few inches at a time along the bed, and see which way the bubble goes.
do you think you should go around with a torque wrench to make sure each bolt has the same amount of torque on it? that way the weight is distributed evenly, or are there other factors to where that wouldnt work? Maybe the fact that the weight distribution isnt even?
I noticed at one point in the process you mentioned you had adjusted "twist" out of the frame. We did not see a process to check if there was a droop or bow from end to end. Does the frame design minimize this problem or is it something you are addressing at a later date?
Why do you not check to see bed is straight? The cneter of the bed may be high or low relitive to the centerline drawn between the chuck and tail stock?
How would you check that? Once he has both the headstock and tailstock end level if he put the level longitudinal on the centre of the ways would it still read level? Since it would be sagging pretty equally from end to end on the level
Edit: nvm I guess he could repeatedly set the level along the ways and work in from the headstock/tailstock ends towards the centre
@@6Drugstep9 Yeah- longitudinal on the carriage and take readings as you step down the bed. I have never done any of this... it seems like it would be as important as twist.
If that machine has been setting in that room for about a week it's acclimated to the room. When you do you check and as far as I'm concerned you can do it now, turn your level 180° in the exact same spot. This will insure the level is reading right and gives you a second opinion. If you put a human hair under one end of that master level it will read .005 off. What I'm saying is it's hard to lay it down perfectly and clean every time. You can mark the surface with a marker and it will sometimes show. Light from an over head light source will draw the bubble. Breath on the glass heavy a watch it move away.
Sorry it will be close enough for anything your doing. Just turn it a couple times a check out what I'm saying.
Great explanation. Thanks, Adam.
You have a lot more patience than me Adam , that would drive me nuts 🤦🏼♂️
A little dab of grease in the recess would probably have been nice, really high load on that small contact area between the adjusting screw and foot. Interesting video none the less. Big thumbs up!
I have a question: How can you be sure that the precise leveling you're doing here won't be immediately ruined by vibrations or any loads that happen during operation? How often do you check the alignment and how well do these machines usually keep their level?
Well, to answer your first question, the precise leveling will absolutely shift under vibrations and loads at first. But, once it's leveled and settled out, a machine won't move much at all under normal operation. Especially bigger ones, that's probably around 10,000 lbs (4500kg) of lathe, some load or vibration isn't going to make a difference.
The rest of the alignment process is much easier, this is just the initial leveling and is the most time consuming. Machines will do what's called "settling," where the castings and the feet and even the concrete underneath the feet will shift slightly under the constant weight. So when you move a machine, you do the initial leveling. Then, a day or two later, you check the level again. It shouldn't have changed much, but it probably settled some and changed, so adjust it back to level. Then start using the machine like normal, and check the level once a week or so and adjust back to level as it settles. Once it stops shifting from week to week, then it's fully settled and level, and you only really need to check it once or twice a year after that.
As I always do when answering questions here, i'll preface that I'm not an expert lol. However, as far as I know if you are using a lathe within the limits it was designed for, particularly its weight and rigidity, vibrations shouldn't significantly move it. The cutting forces also can't move it as they don't cause any external reaction force to be placed on the lathe, though I suppose it could affect the "twist" of the ways, but again it shouldn't if used within the design limits. Not sure on how long you can assume they stay level though.
kinematic mate that forms between the shoes and the floor due to the incredible mass. sheldon nailed it.
@@sheldendowden3096 thank you for the detailed answer.
@@sheldendowden3096 Thanks Sheldon for that explanation, answered the silly questions I had. As the power engineer in the comment section, all I can say is this. 'We' will provide Adam with the necessary energy to keep him busy for a long time, to keep making interesting videos we can 'ALL' learn from. Cheers.👍.
Thank you Adam I love watching your videos if I was close by I would love to learn more from you I am watching from South Africa
Cool to see the difference in precision levels... :-)
Gooood afternoon from central Florida! Hope everyone has a great day!
do you check center to headstock and center to tailstock to make sure it isn't high or low in the center verses the ends or did i miss it
I was thinking the same
That's what test cuts are for. ;) But you have to have the lathe level first. You make a long cut on a bar and measure the difference in diameter at the ends, then adjust the tailstock to even it out by moving it side to side or shimming the tailstock for center height.
I’m not a machinist by any stretch of the imagination, but I do enjoy watching your videos and learning how you do things.
Watching you set the lathe to a precision level a question comes to mind. Won’t all the precision leveling be thrown off due to the metal expanding and contracting due to temperature changes in the shop?
Good job and good to see that smile.
Really like that lathe. Proper, heavy old school large lathe, great quality bit of kit.
That would be the first project at the new shop. The T nut
Amazing, truly a master at work.
Adam one question: you levelled on the Y axis at the headstock, tailstock and in the middle, why didn't you level on the X axis at those positions too? It could be high at either end or have a hump or dip in the centre.
You will have to rechecked it, until it is the best possible, that is why this kind of task usually can turn in to a "chasing tale task" only the experience will help you with the time to know when is enough... Or is something wrong... "iteration process" is ti called
As Adam mentioned, the biggest issue is twist. That causes taper in a length of material you are machining. There are other areas Adam has to check like tailstock alignment but twist has to be sorted first. The longitudinal imperfections on the X axis make minimal difference to the accurate operation of the lathe (as long as you get it close in the first place - which Adam did). If you were really pedantic then you could recheck the X alignment and readjust that but then the more important Y alignment would go out of whack again - you end up chasing your tail for many, many hours. Also remember that the accuracy of the Starrett level is 0.0005" per ft. If lathe is out by even 0.001 per ft on the X axis, then that is not end of all accuracy of any finished machined items.
Amazing how sensitive the 199 is, it moved a lot while the Lufkin never even moved, how do you tell if the middle is higher or lower than either end, did you have the levels length ways ie parallel with ways, I couldn’t tell from the video, I ask out of curiosity’s sake as I would happily watch a 4hr video on precision levelling and the tools used.
Very cool, I have this project coming up on my lathe. Would have like to see how your adjustments that took the twist out might have effected the level from head to tail stock. Also, how often do you check the level of a machine? Seems like it can change over time. Thanks very much for sharing Adam.
Did both ends and then the middle. As a sanity check, see if there is a hump in the middle. Probably not, because of the gentle way you did it.
Hi Adam, You spent a great deal of time leveling the machine tide to side to get any twist out of the ways. Shouldn't you also check it for level end to end to make sure you don't have any bow longitudinally in the ways? Just an observation of maybe an oversight. Chris.
Another vote for Adam's awesome care and attention to detail 👏
Just 2 questions though...
(1) Will the vibrations from running the machine create much movement in these leveling feet creating a need to re-level the lathe after a run in period?
And (2), what's the most significant issue caused by an unlevel machine?.
I assume machine longevity is a big factor, but does a slightly unlevel machine translate into noticeable differences in the workpiece?
A good question...its borderline, sometimes yes, sometimes no, but always good practice to do a settlement check after about 3 months. (but rarely done in industry)
2) Vibrations (chatter), just gravity I guess.
Nice video Abom. I have just posted a video of repairing the 18" Rabone, Starrett copy level. Thanks for sharing.
Regards.
Steve.
One more video closer to big boy chips. Nice work!
Good job 👍 Adam thanks for sharing
No leveling end-to-end? Is it possible that the center of rotation of the chuck isn't in line with the center of the tail stock?
I'm curious about level from headstock to tailstock, parallel to ways. Seems to me that with setting cross level at headstock with the feet under chuck, the weight of the headstock could cause some bow in the bed. By this, I mean the level set parallel to the bed, moving from head to tail, you could see head low, bubble to right, then level halfway between head and center support, then moving towards center support bubble moves to left, then moves to level over center support.... same with section between center support and tail. It was so easy to see a little twist in bed, seems like wavy or bow along length of bed is likely.
It would of been good to see a dial gauge measuring the movement of the base. So we could see how much it was actually moving
That would have been interesting.
Even wood workers have to flatten our stones, to keep chisel and plane blades square.
Great video on leveling a longer lathe. I'm current trying to level a 23x118 lathe and from this video, i understand leveling front to back. But what about headstock to tailstock (in length)? Is this not necessary?
Thanks for input.
There is the slightest friction in a bubble ,
A slight tap with the eraser end of a pencil, can even get the bubble to react ..
Wondering why you didn't put high pressure grease between the leveling screws and the pads?
Mirror might be useful to see the level... If you don't go all newfangled with a wireless camera do that you can watch the bubble as you work the spanner.
Great video Adam, learned a lot.
Adam: looks at one of the height adjustment screws
*Starrett 199 bubble moves 4 lines*
As the, obviously poorly poured slab which has cracked in two directions, what are the chances of further movement which may effect the level of the lathe? Adam - another stellar demonstration of lathe levelling. If dad and grandad could see this Adam they'd be overwhelmed with joy 🙂
that was a lot of work , very good
How do you know your Starrett level isn't sitting on that little bolt or a raised edge since it's so much bigger than the Lufkin?
Adam, I notice that on the monarch at your house the feet (pucks) that you made for that machine were hollowed out bottoms? On the pacemaker you did not what was your reasoning on the decision?
Thank you,
JC
I would like to see how you clean the ways. Like your videos very much. Thank you! Joel
I am actually interested in seeing a check of spindle to bed parallel, since all the weight there I wonder if the 4 headstock leveling bolts can actually bend the spindle bore up and down relative to the bad.
Surely the cracks in the concrete at the back of the slab the lathe is sitting on can't be ideal. This is a new building so perhaps the thickness isn't what it should be. This lathe is going to move there's no question to it.
Concrete always cracks, even post tensioned concrete which is considered uncracked concrete. This is why we have control joints, wire mesh, rebar at corners, shrinkage compensating admixtures and such. Unless the cracks are very wide, it’s likely temp/shrinkage cracking.
Nothing I can do about the cracks. They’re there and we’ll have to work around them and check the machines occasionally.
Concrete shrinkage cracks are different to ground moving cracks. Hopefully the concrete was laid on well prepared bed.
Hah, I just watched the February video about turning the pucks, now this shows up.
If it works for you Adam, It'll work for me. Looks good 👍. Cheers.
I cant be the only one who was shouting "Ho!" like I was there watching the level :)
Do you, or did I miss, leveling end-to-end? Really enjoy your videos, a great learning experience for me.
Thank you very much for your good content.
Adam, did you level along the bed too, you've shown us minimising the twist end to end, but does the bed hog up or sag down? I do understand (with a used machine) that it's a balancing out process and could never be perfect in all planes.
Also given how sensitive the Starrett level is, how much does it really relate to how the machine will react to machining loads, you pointed out not pushing or leaning on the bed while levelling because it would distort the readings if that is so then how will the 'level' of the bed be distorted while operating the lathe?
Lastly when all is at optimum level and well settled down given how delicate the levelling is, would some gentle toe clamping to the floor the level bolts (and the pads) be useful if only to prevent the lathe 'washing machining' out of place over time and upsetting the levelling?
I'm not questioning your proceedures or intent, I just want to know 🙂 come to think on it, there's an SnS right there, or two even ;-)
Why didn’t you turn your level 90 degrees and check for concave/convex in the bed?
From watching your videos it's pretty obvious you really prefer Starrett tools... and I was just wondering what got you into Starrett so much?? I am all the way in on Mitutoyo tools myself but I think that came from tech school..that's mostly what we had.. I mean we had some of everything..but what influenced you to make the decision to be all out Starrett?? I have a couple Starrett dial indicators but they are old..were old when I got them so probably not the best thing to base judgement from lol
I love your channel very entertaining and informative thanks and I hope to hear back from you on the choice of tooling question lol
You must do a reproduction list on the subject of "leveling machine tools" so valuable knowledge... GRACIAS desde locombia
Thank you very much
Hey don’t you have to check the longitudinal level at each end in case it is bowed up/down in the middle? Or did I miss that? With so many feet this lathe looks fiddly to level. Well done!
Question, I understand you have the twist out of the bed. but, lengthwise, is it now like a roller coaster?
Another quick question on the levelling, with how good you got the scales on this lathe, what tolerance in degrees do you think you have? For various reasons I find it difficult to use bubble levels, I have a .01 (of a degree) resolution digital level but I'm wondering if it's really good enough.
I just did a quick calculation and 0.0005 inch/foot can be converted to 0.00239°
Your level with .01° resolution would be like a level with roughly 0.002 inch/foot
So it's a bit less precise. Also, you can't read "between the lines" on a digital level
That would work to “rough level”. For absolute precision a Master level with .0005” per foot graduations must be used.
Whilst the digital level might have a resolution of 0.01 of a degree, it won't have the precision or repeatability required for truly accurate result.
Try measuring something by lifting and placing the level, then flip the level 180 degrees, and measure it again. Then repeat that 5 times in the same place, giving 10 measurements. What's the spread of measured values?