# Accuracy of Machinist Levels



## ChandlerJPerry (Aug 15, 2020)

What is everyone's preferred minimum accuracy for a machinist level? I see the Starrett 98 mentioned a lot which I believe is .005" per graduation on the vial. I know quality measuring equipment isn't cheap, but my budget is unfortunately tight (laid off due to covid related slowdowns), so I was wondering if anyone has any experience with other levels and what accuracy is really useful for the home shop. Something tells me a .0005 level might just lead to ripping hair out in the garage! 

I was looking on eBay and found a 4" Stanley No. 34 for a reasonable price, it looks very similar to a Starrett 98 but I can't find any published statistics on the accuracy of that model. There are also plenty of Stanley No. 36, 37, and 237 on eBay which have adjustable precision ground glasses, but are marketed more towards high precision carpentry and plumbing, etc. in vintage Stanley catalogs. So what levels are everyone using for their machines?

Just for showing off's sake, here's my newest level that I purchased on a whim before realizing it wasn't nearly precise enough. 
It's a Stanley No. 39 1/2, 6" long, marketed as a machinist level in their catalog but definitely more suited to general leveling tasks, it may be more precise than a similar carpenter's level, as the glass seems significantly longer to me and it is enclosed in a heavy cast iron body. However it lacks adjustability and fine graduations for precision leveling, as well as the glass not being precision ground. It is very pretty though! The logo dates it as being from 1922-1935.


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## GunsOfNavarone (Aug 15, 2020)

Personal experience, and I wolud go look at the thread on this subject by @Aukai , I wouldn't even recommend the SUPER high res levels. It's just not necessary for what we do in the home shop and it will frustrate the heck out of you.


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## benmychree (Aug 15, 2020)

A level with .005 graduation is nearly worthless for machine leveling, it will only get you close enough to go to the .0005 grad. level,  Having said that, a precision level is not entirely necessary for small lathe (alignment), the two collar method will be adequate for that chore.


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## Papa Charlie (Aug 15, 2020)

I purchased a Starrett 98-6 on Ebay for around $90. Thought I got a good deal. In excellent condition in original box. There is also the Polish made ones on Ebay. From what I have heard, they are very good quality, but just less known. But I am no expert on these.


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## Larry$ (Aug 15, 2020)

20+- years ago I bought a precision level made in Poland. I was setting up CNC equipment and this one was recommended by a service tech. I'm pretty sure you can still buy them new or find a used one that hasn't been abused. Heavy cast iron V bottom. Plastic finger holds so the heat of your hand doesn't throw it off, a small cross vial. Very nice BUT it can drive you nuts because it is so sensitive that a sheet of paper under one end  (it's 10" long) will move the bubble quite a lot. 

I don't know what needs to be that level in a hobby workshop. A lathe can be out of level by an inch and not affect much of anything.


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## GunsOfNavarone (Aug 15, 2020)

Yes, the most frustrating time of my life in the last 10 years was trying to calibrate my machinists level, A h3ll I would only wish on my worst enemy. I still have nightmares and wake in a cold sweat....Sorry, I meant to say it wasn't that bad.


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## RJSakowski (Aug 15, 2020)

Levels are one of the few self proving metrology instruments.  It is capable of being calibrated using itself and a relatively flat aqnd level surface.

A level has only two important requirements; sensitivity and a flat bearing surface.  Garden variety levels typically are fairly low sensitivity.  A half bubble off level is around 1/4"/ft.  That is .250"/ft.  This includes carpenter's and plumber's levels. Contrast that with the Starrett 98 series levels which have a sensitivity of .005"/ft.  That's fifty times as sensitive.  A step further is the Starrett 199 series which has a sensitivity of .0005"/ft or ten times more sensitive yet.For those not willing to shell out for a 199, there are levels on eBay made after the Polish level design for well under $100.  The one that I bought is an 8" level and has a sensitivity of .0005"/10" or .0006"/ft.  So far, I have not had any problems with it.


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## pstemari (Aug 15, 2020)

(redundant)


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## ChandlerJPerry (Aug 16, 2020)

Thank you everyone for the advice! Are these the inexpensive levels on eBay that everyone is speaking of? I can find what looks like the same 8" level from any number of sellers for around $60. I am concerned that I won't be able to level my lathe very precisely, I'm bolting it to a 2" thick industrial countertop made of very heavy particle board, which I think is rigid. However the legs are 4x4 posts that are braced with 2x6, I am worried that with the tendency of wood to expand and contract that this could introduce twist. Will using such a precise level with my chosen mounting method be a hopeless endeavor?


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## mikey (Aug 16, 2020)

Chandler, perhaps a better way to discuss precision levels is to tell you what the overall procedure is, so that you can understand the role a good level plays.

Leveling a lathe simply means we are trying to get the ways of the lathe to be co-planar so that there is no twist across the bed. The reason we do this is because an un-level lathe will turn a taper into your work piece. The way we remove twist is to use a level across the ways at the headstock end and at the tailstock end and use leveling adjusters under the lathe, under the stand or both. When both ends of the lathe are level that indicates that both ways, front and rear, are in the same plane. Typically, using a level like this will get your lathe very close to level but it may/probably will still produce tapered cuts unless you fine tune the leveling even further. The way we do this is with a 2-collar test that allows you to really fine tune your levelers to ideally remove all evidence of a taper in the work piece. Go look up the 2-collar test to see how this is done. When both collars are the same diameter after test cuts, the lathe is level. Know that all lathes move and a preliminary leveling must be repeated in a week or two and then checked every so often to make sure nothing moves. 

Now, with that background, the role of a precision level is the same as a less precise level. For example, a Starrett 98-8 is sensitive to 0.005"/foot, whereas the level you showed above is sensitive to 0.0002"/foot. As noted by the other guys, a 98-8 is not all that sensitive but it will still get you close enough and you can use a 2-collar test to get you the rest of the way. The advantage to the more sensitive precision level is that it will get you closer a lot faster, so that you will do far fewer trial cuts with your 2-collar test. This may not seem like a big enough difference to justify the cost of a precision level but it can mean hours of saved time, literally. 

I have both a Starrett 98-6 and a Kinex precision level sensitive to 0.02mm/Meter and the difference in time that the better level saves can be significant. I use the Starrett to get me close, then switch to the Kinex to get me closer. When the Kinex says I'm level, I am maybe one or possibly two cuts away in a 2-collar test to dead level, and we're talking about resolution in the low tenths to zero over a 10-12" distance. 

So, think of the need for a precision level in terms of time and frustration. The more sensitive the level, the less time you will spend doing test cuts. 

As for your bench, as long as it is solid and the whole top provides a stable platform, it should be fine. Just make sure you have some way to level the lathe and the stand so you can make the adjustments you need.


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## benmychree (Aug 16, 2020)

ChandlerJPerry said:


> Thank you everyone for the advice! Are these the inexpensive levels on eBay that everyone is speaking of? I can find what looks like the same 8" level from any number of sellers for around $60. I am concerned that I won't be able to level my lathe very precisely, I'm bolting it to a 2" thick industrial countertop made of very heavy particle board, which I think is rigid. However the legs are 4x4 posts that are braced with 2x6, I am worried that with the tendency of wood to expand and contract that this could introduce twist. Will using such a precise level with my chosen mounting method be a hopeless endeavor?


Well, yes, that is why God made cast iron.


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## projectnut (Aug 16, 2020)

If you're not hung up on names like Starrett, Mitutoyo, Brown & Sharpe or other more common names you might want to check out Moore & Wright.  While they are less popular in the US they are a little more accurate (.0035" per foot) than the Starrett 198 series.  In most cases they are also less expensive.  They are more often referred to as "Engineers Levels" rather than "Machinists Levels"

I purchased a 12" model on eBay earlier this year and have been very happy with it's performance.  It's in like new condition and came complete in the original box.  Like anything on eBay prices are all over the country side.  I paid $110.00 with shipping included


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## Choiliefan (Aug 16, 2020)

VIS is the brand of Polish levels.
They made xlnt micrometers as well.


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## GunsOfNavarone (Aug 16, 2020)

I wouldn't use that board you speak of for mounting a lathe. I have 2" think butcher block Over the last 2 years with a lathe placed on it, well, it's not flat enough anymore to even approach it with a machinist level. If you have some solid supports under the wood, spaced not TOO far apart, that may help greatly. I am considering ordering the manufacturers table to fix my problem,


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## Larry$ (Aug 16, 2020)

Mikey's explanation is good. I'm always bothered by the term "leveling." The use of a level is just an aid in getting the bed to not have a twist. The level can be off by a lot and not matter in the least as long as you keep it in the same orientation and get the bubble to settle in the same spot for each end of the lathe. The sensitivity of the level is what determines the repeatability. We are getting off into an area of discussion beyond what is necessary for your lathe truing up. Everett's workshop has an easy to follow video for making and using the bar Mikey is talking about. 




. 
When you use one of those bars it is best to make sure the cross slide has been advanced into (to eliminate backlash) the work then ideally locked so there is no creep. It's worth keeping in mind that your lathe, or mine for that matter, was never intended to be tool & die maker accurate. 

Now back to your bench. I can't see the underside of the top. But if there is no framing below the top you will have a bigger problem. Particle board will sag over time with the load of the lathe on it. PB is also compressible. So the force necessary to take any twist out of the cast iron may be more than the PB can resist and it may simply dent rather than move the cast iron.  The 4x4 legs are OK since wood moves very little in the length wise direction. A steel bench would be better, maybe some day. Concrete moves so don't put the bench over a control joint or crack.


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## pacifica (Aug 16, 2020)

ChandlerJPerry said:


> What is everyone's preferred minimum accuracy for a machinist level? I see the Starrett 98 mentioned a lot which I believe is .005" per graduation on the vial. I know quality measuring equipment isn't cheap, but my budget is unfortunately tight (laid off due to covid related slowdowns), so I was wondering if anyone has any experience with other levels and what accuracy is really useful for the home shop. Something tells me a .0005 level might just lead to ripping hair out in the garage!
> 
> I was looking on eBay and found a 4" Stanley No. 34 for a reasonable price, it looks very similar to a Starrett 98 but I can't find any published statistics on the accuracy of that model. There are also plenty of Stanley No. 36, 37, and 237 on eBay which have adjustable precision ground glasses, but are marketed more towards high precision carpentry and plumbing, etc. in vintage Stanley catalogs. So what levels are everyone using for their machines?
> 
> ...


This is a good price and quality for new : https://taytools.com/products/kinex-86-2-precision-inspection-machinist-spirit-level . I have several of their machinist squares and they follow the specs exactly and are well made.


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## mikey (Aug 16, 2020)

pacifica said:


> This is a good price and quality for new : https://taytools.com/products/kinex-86-2-precision-inspection-machinist-spirit-level . I have several of their machinist squares and they follow the specs exactly and are well made.



That is a really good price on a very nice level. Kinex makes good stuff!


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## matthewsx (Aug 16, 2020)

I just bought this one from Accusize in Canada. I'm sure it's Chinese but then so is my lathe, I've been happy with other stuff I've bought from them.

John


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## GunsOfNavarone (Aug 17, 2020)

I have the Accusize level. It for sure works. I am interested to see Chandler try and get his lathe level. With my 2" thick butcher block table and a level that is too sensitive, it was impossible. When I got it close enough and then tried then to use it on the ways.....forget about it. I think newbs just work on getting it to cut equally on the 2 collar test and screw everything else. I will say, getting the Tormach level was MUCH easier, but there is no twist to deal with. I really want a solid metal table/stand for the lathe....and to add something like @RJSakowski added to the lathe as adjusting feet.


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## mikey (Aug 17, 2020)

GunsOfNavarone said:


> I have the Accusize level. It for sure works. I am interested to see Chandler try and get his lathe level. *With my 2" thick butcher block table and a level that is too sensitive, it was impossible*. When I got it close enough and then tried then to use it on the ways.....forget about it. I think newbs just work on getting it to cut equally on the 2 collar test and screw everything else. I will say, getting the Tormach level was MUCH easier, but there is no twist to deal with. I really want a solid metal table/stand for the lathe....and to add something like @RJSakowski added to the lathe as adjusting feet.



I really have to wonder why you are having so much trouble leveling your lathe because there really isn't a whole lot to it. There are only a few principles that need to be attended to and leveling should go pretty easily. 

If you think about it, what we are trying to do is twist or untwist the bed so we can get it aligned. In order to do that, we have to have some mechanism that applies or relieves pressure on the bed. On larger lathes with solid stands that are free standing on the ground, we use leveling mounts/feet to apply pressure to the lathe that is solidly bolted to the stand. Some smaller lathes, like my Emco lathe, use adjustable levelers under the feet of the lathe AND under the cabinet/stand. Many hobby lathes require shims or the fabrication of adjustable levelers under the feet of the lathe; these are often mounted on tool chests or shop-made stands of various designs. The common factor here is that there must be some method of adjusting or applying pressure to the lathe structure in order to move it, and it must be finely adjustable enough to do the job. 

When leveling the lathe, the level must sit on a common surface that is available at the headstock and tailstock ends of the bed. Most folks seem to use the ways of the lathe as this common surface. Others, like myself, prefer to sit the level in a precise position on the cross slide. Using the cross slide is common when the front and rear ways are not at the same elevation. Whichever way you choose to do it, you need to do it consistently and precisely. This is especially true for lathes that may have some wear on the ways. 

Finally, you have to understand that trying to twist a large piece of cast iron does not happen in seconds. It can take minutes to hours for the bed to move, and the bigger the lathe the longer it can take. This is not a consistent thing; some lathes move more readily than others. My Emco lathe will move within 10 minutes and then settle. I've leveled a little Compact 8 lathe that took almost an hour before it settled and a SB13 that took several hours for the bubble to stop moving. If you make an adjustment and the bubble moves, watch it for 5-10 minutes to make sure that the bubble doesn't move further. If it does move further, wait until it stops. 

All lathes move over time and need to be adjusted. This is just the nature of the beast. You should check your level-ness every so often and especially if you turn a large work piece or something that was out of balance. Guys who think they only have to level once are just naive because the reality is that lathes move. 

So, if you're having trouble I suggest you look at how your lathe is mounted and how you're adjusting it. It isn't the level that is the problem.


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## GunsOfNavarone (Aug 17, 2020)

@mikey The lathe has been on it long enough that it has slightly bowed the center. Now with a level that can pickup (heavily) something as thick as a piece of paper, a slight bow feels more like an Evil Knievel ramp. The level isn't the problem perse, it's mounting it to something organic. I think the OP was going to use a type of partial board. Again, I was used to normal level when I went to calibrate mine. I have a new respect for what "level" means. I do not want anyone to believe I nailed it on my lathe, but when I say close, it probably equates to 20 thou over 10". Many would shake their heads at that, but I'm realistic and my table changes every time is rains. I look at the work I'm doing and accept that close is good. If I insisted on perfect with my setup, I probably would have blamed my level and tossed it in the scrap heap. I love my level now that its....level.


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## Larry$ (Aug 17, 2020)

I agree with Mikey. Cast iron moves, actually pretty easily. If you have a relatively light lathe and a light stand/bench. the bench/stand may not have enough rigidity to force the lathe into position. Over time the two will reach some sort of compromise. Using a very sensitive level you can check for twist. Record your readings and go back later and see if the readings are the same. Turning a test bar between centers is very accurate, for that one location of the tail stock. It says nothing about the overall shape of the bed. Putting the level on the carriage so you can traverse the length of the bed is a good method BUT because the carriage has more weight and more force affecting the front than the rear, it will wear the front of the bed more than the back. The result will look like a twist but only be uneven wear. The more used the lathe the more variation. My Polish made level could drive me nuts on a worn lathe. Could never get there. My lathe and cast iron stand weigh about 2700 #s. I don't know if they are dowel pinned or just bolted together. Likely just bolted. That being the cast there may be enough stress to move the two parts relative to each other over time. I was careful to place it on one slab of concrete, no control joint or crack under it. Concrete moves. How far do we want to take this?


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## GunsOfNavarone (Aug 17, 2020)

Though I might come off a little over the top with my relationship with machinist levels, let me remind you the title of this thread. I remember a couple months back, the frustration myself and another member here were going though trying to calibrate our levels (ones that were disassembled out of calibration) it was very humbling. I LITERALLY have 15.... Maybe more, hours trying to sort it out. When I was done, i saw just how sensitive it was. There was no metal feeler gauge i could put under one side and not nearly peg it to that side. For any newb with a machinist level, they don't know to let it sit in the room your using it in for a couple hours to settle to that temp, don't touch it with your hands using it, at least not for long. None of this is crazy talk, and that to me IS crazy.


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## ChandlerJPerry (Aug 17, 2020)

I'll probably make a separate thread when it actually comes time to do any leveling. Currently the machine is in pieces and is slated to receive a thorough cleaning and maybe new coat of paint. This topic was just one that came to mind since it's something I know I will need to be thinking about moving forward when the machine is reassembled. I do like the idea of leveling feet on the machine itself so that I don't have to struggle with shims for adjustment. It's an Atlas QC54 so it does not have any leveling provisions built in. Does anyone have images or links for a suitable style of leveling foot to purchase or make? After reflecting on it briefly, I would think one would want the foot to bolt to the work bench, and then have a mechanism (simple nut and thread) for adjusting the lathe.


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## mikey (Aug 18, 2020)

Chandler, have a look at this thread. TerryH did a nice job with his mount. I suggest you consider it and I would also suggest that you ALSO put levelers on each leg of the bench. It may surprise you how useful tweaking a leg leveler can be when trying to fine tune the level of your lathe. To be clear, leveling adjusters under the feet of the lathe AND under the legs of the bench can alter the overall level of the lathe once the lathe is bolted down.


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## Optic Eyes (Apr 9, 2021)

mikey said:


> Chandler, perhaps a better way to discuss precision levels is to tell you what the overall procedure is, so that you can understand the role a good level plays.
> 
> Leveling a lathe simply means we are trying to get the ways of the lathe to be co-planar so that there is no twist across the bed. The reason we do this is because an un-level lathe will turn a taper into your work piece. The way we remove twist is to use a level across the ways at the headstock end and at the tailstock end and use leveling adjusters under the lathe, under the stand or both. When both ends of the lathe are level that indicates that both ways, front and rear, are in the same plane. Typically, using a level like this will get your lathe very close to level but it may/probably will still produce tapered cuts unless you fine tune the leveling even further. The way we do this is with a 2-collar test that allows you to really fine tune your levelers to ideally remove all evidence of a taper in the work piece. Go look up the 2-collar test to see how this is done. When both collars are the same diameter after test cuts, the lathe is level. Know that all lathes move and a preliminary leveling must be repeated in a week or two and then checked every so often to make sure nothing moves.
> 
> ...


I am a level machine kinda guy, but Warner Swazy didn't worry about that, their levels had an adusttable vial so you adjusted level by the headstock and made the tail end match


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## sdelivery (Apr 9, 2021)

GunsOfNavarone said:


> Though I might come off a little over the top with my relationship with machinist levels, let me remind you the title of this thread. I remember a couple months back, the frustration myself and another member here were going though trying to calibrate our levels (ones that were disassembled out of calibration) it was very humbling. I LITERALLY have 15.... Maybe more, hours trying to sort it out. When I was done, i saw just how sensitive it was. There was no metal feeler gauge i could put under one side and not nearly peg it to that side. For any newb with a machinist level, they don't know to let it sit in the room your using it in for a couple hours to settle to that temp, don't touch it with your hands using it, at least not for long. None of this is crazy talk, and that to me IS crazy.


Best one is when someone wipes the dust off of the vial....I just go get coffee and let it normalize again.
Customer opens the door in cool weather and the level changes....


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## Optic Eyes (Apr 9, 2021)

I might mention the level is parallel to the earth’s diameter at the latitude it was set at You only have 100 miles north and south of that latitude before it might go out of correction Machinist levels aren’t really all that accurate coincidence levels are much more accurate time cost of course a whole lot more my coincidence levels are accurate to one second to a park or 1 inch to 200,000 inches


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## ErichKeane (Apr 9, 2021)

ChandlerJPerry said:


> Thank you everyone for the advice! Are these the inexpensive levels on eBay that everyone is speaking of? I can find what looks like the same 8" level from any number of sellers for around $60. I am concerned that I won't be able to level my lathe very precisely, I'm bolting it to a 2" thick industrial countertop made of very heavy particle board, which I think is rigid. However the legs are 4x4 posts that are braced with 2x6, I am worried that with the tendency of wood to expand and contract that this could introduce twist. Will using such a precise level with my chosen mounting method be a hopeless endeavor?


Don't buy that.  I have one, and it is finicky, inconsistent, and just overall terrible.  I have no idea how they managed it, but I don't get the same reading every time.


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## Choiliefan (Apr 9, 2021)

Optic Eyes said:


> I am a level machine kinda guy, but Warner Swazy didn't worry about that, their levels had an adusttable vial so you adjusted level by the headstock and made the tail end match


That's an interesting approach to taking the twist out of a bed.
At first blush, I like it.


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## Larry$ (Apr 10, 2021)

About particle board tops: The stuff sold at the big box stores is less dense/stable than the industrial board (48#s / cu. Ft.) But both are pretty unstable with changes in moisture. They are also quite compressible. Less than ideal for a machine bench. You can slow the changes by trying to seal the board. You have to treat both sides the same and especially the edges. If you don't treat both sides the same the panel will curl (even worse!) A laminated maple top would be better. Seal it with several coats of urethane varnish, all around.  Best alternative: STEEL!


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## Optic Eyes (Apr 11, 2021)

Choiliefan said:


> That's an interesting approach to taking the twist out of a bed.
> At first blush, I like it.


Warner and other Hand screw machines would machine quite big parts repeatedly year after year many times 3 shifts a day, production would never consider changing jobs on a machine to distribute wear evenly, until Repairman told them to use a different area of the machine, when they wore out we bought another one.
The point is you can overreact on engine lathes, many Tool room lathes like Harding's are on three point suspension and only need simple leveling, Colchester's from England are as well and was the Navy's choice for some time.


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## Optic Eyes (Apr 28, 2021)

Choiliefan said:


> That's an interesting approach to taking the twist out of a bed.
> At first blush, I like it.


The problem with levels is you are adjusting a surface using qualitive analysis, if you used quantitive analysis by comparing the surface to a datum you would know how high or low each spot was. Optics does this much faster than using levels giving direct readings of elevations.


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