Digital level opinions

Discussion in 'Workshop Tips and Secrets / Tools' started by Little Scrapper, Feb 6, 2016.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Feb 8, 2016 #41

    Little Scrapper

    Little Scrapper

    Little Scrapper

    Well-Known Member HBA Supporter

    Joined:
    Jan 3, 2014
    Messages:
    5,249
    Likes Received:
    3,153
    Location:
    Wisconsin
    Ekimneirbo.

    As far as the Johnson level, here's the issue I had.....

    I shimmed one side .020" at a time and kept stacking it until it settled on 1/10 of a degree. I pulled the shims out and when sitting with no shims it still registered 1/10 when it should have been 0.

    So I recalibrate it.

    I did exactly the same thing as before but this time the same quantity of shims registered 0. I think I added 3 more shims and it finally hit the 1/10 mark. It made me nervous enough where I knew I couldn't depend on it.

    I'll let you know how I like the Stabila. I'm not biased and have no loyalty to Stabila so I'll give an honest review.
     
  2. Feb 8, 2016 #42

    ekimneirbo

    ekimneirbo

    ekimneirbo

    Banned

    Joined:
    Oct 31, 2014
    Messages:
    1,009
    Likes Received:
    324
    Location:
    Deep South
    . Yes, I realize you are just trying to get honest information to help everyone make a good decision. Here is the thing though, you have to have realistic expectations on the results you get from any type of measurement. When dealing in thousands of an inch and trying to project that over a distance, it is basically impossible for a homebuilder to do so accurately. The 4 foot level will get you pretty close over the four foot area it spans. From that point on, its really not going to continue that accuracy simply because whatever +/- accuracy tolerance the levels system has will begin to grow. Also the material you are working with will have variations. To me, for a homebuilder trying to build a good FLAT and LEVEL work table I would use a water level to set the four corners and maybe then establish a lazer reference . Here is what I mean by that. Get your four corner posts set. I would run them all the way from the floor to the ceiling and get them (semi) permanently attached to the floor and ceiling using your level to establish reasonable verticality. Use a water level to make marks on each post for the "level" table supports to fasten to. Put MDF on for a table surface because it is remarkably flat and consistant. I also recommend that when buying the MDF that you make a measurement yourself to locate the center of the MDF. Mine was 49" (yes 49) wide which allows a little overhang on the sides and 48" aluminum can be stored underneath on shelves you add. Anyway, the exact center of the MDF is located before purchase and most home supply stores offer a free cut. Have them score a 1/16 or so groove longways on the MDF with their panel saw. Then once your table is built you have a handy centerline established for setting all your measurements. Take your lazer level and place it on the table surface and point the lazer at a small framing square sitting on the tables surface about 1 foot away from the level. Make a mark on the square where the lazer dot hit it. Now move the square about the table surface and see it the dot hits the same spot or if you need to shim here and there.
    One point here. This is another situation where the shorter lazer level is better than the longer one. The area where the lazel level sits is smaller and more consistant than a larger area might be.



    Here are some pictures I added later. They show the level sitting on my computer desk. I added 3x5 cards under one end. Basically it took 2 thicknesses of the cards to effect a .1 (1/10) degree change.
    You should also remember that with a digital readout that there is a range of movement required to make a numerical change unlike a micrometer or dial indicator where direct reading shows all portions of a change in the reading. In other words you can move a level a small amount without a reading change,that doesn't mean the level is incorrect..it just hasn't moved enough to effect the change. Also, sometimes the level is exactly right at the change point and may initially waver a little. You can see the number of cards used in each picture.

    (Additional note: Using a 4 foot level would mean that the end of the level would have to move much further than the 3x5 cards did on my short 10" level. Those 5 cards probably would not have shown any change on the 4 foots digital readout. I felt that should be pointed out in fairness to the 4 foot level. Its not necessilary that the Craftsman has a better digital unit, its just that ALL the actual digital readouts are small/short units embeded in the level and ALL longer levels will require more movement to show a change.)



    DSCN4554.jpg DSCN4555.jpg DSCN4556.jpg DSCN4557.jpg DSCN4558.jpg
     
    Last edited: Feb 8, 2016
    Little Scrapper and Joe Fisher like this.
  3. Feb 8, 2016 #43

    cheapracer

    cheapracer

    cheapracer

    Well-Known Member

    Joined:
    Sep 8, 2013
    Messages:
    5,059
    Likes Received:
    3,327
    Location:
    Australian
    Seen digital out too so i never lose my habit of turning the level around 180 degrees to make sure it's level that way also and splitting the difference if it is.


    ****, that must be some exciting place to shop in!!
     
  4. Feb 8, 2016 #44

    BJC

    BJC

    BJC

    Well-Known Member

    Joined:
    Oct 7, 2013
    Messages:
    8,901
    Likes Received:
    5,750
    Location:
    97FL, Florida, USA
    I was given a level laser and it is handy to have, but mine lacks the resolution available with a good water level. The problem with mine is the "dot", which is oval in shape, with indistinct edges, and about 3/32 " high.


    BJC
     
    Little Scrapper likes this.
  5. Feb 8, 2016 #45

    ekimneirbo

    ekimneirbo

    ekimneirbo

    Banned

    Joined:
    Oct 31, 2014
    Messages:
    1,009
    Likes Received:
    324
    Location:
    Deep South
    As I mentioned, I think the water level is best for establishing the initial flat plane for the table, but once you have the flat surface to work with, I don't know a good way to use a water level at that point,

    Most lazers (at least low dollar ones used in levels) are going to have the beams intensity and clarity diminish as distance increases....mine does. Try this with your lazer. Once the table surface is established and you

    put the square appx 1 foot from the end of the level to see where the beam hits.....take a fine line sharpie marker and make a reference line all the way across the square. Then set the lazer on the table and try

    pointing at the square now sitting about 14 feet away. While the lazer is not as sharp, you should be able to see if the line is in the center of what you do have. It may vary with different brands. As I said before I think

    the Craftsman ones are a good bang for the buck. Buyers should also realize that not all digital levels come with the lazer feature.

    DSCN4562.jpg DSCN4561.jpg
     
    Little Scrapper likes this.
  6. Feb 8, 2016 #46

    cheapracer

    cheapracer

    cheapracer

    Well-Known Member

    Joined:
    Sep 8, 2013
    Messages:
    5,059
    Likes Received:
    3,327
    Location:
    Australian
    My laser level emits a constant red line, a 'horizon' so to speak.
     
    Little Scrapper likes this.
  7. Feb 8, 2016 #47

    BJC

    BJC

    BJC

    Well-Known Member

    Joined:
    Oct 7, 2013
    Messages:
    8,901
    Likes Received:
    5,750
    Location:
    97FL, Florida, USA
    Mine does too. The dot is the illuminated area of the laser beam where it shines on a plane perpendicular to the beam. You can see one, and see the too-big size, in a post above.


    BJC
     
    Little Scrapper likes this.
  8. Feb 9, 2016 #48

    Little Scrapper

    Little Scrapper

    Little Scrapper

    Well-Known Member HBA Supporter

    Joined:
    Jan 3, 2014
    Messages:
    5,249
    Likes Received:
    3,153
    Location:
    Wisconsin
    Had surgery today on a tooth that was cracked in to the gum line so I'm just now waking up and able to read the comments. All good stuff here guys. Thank you!

    I'm really getting curious now on the Stabila that arrives Wednesday. I have a really nice spirit level that I'm gonna check it against. Should make for good commentary.
     
  9. Feb 9, 2016 #49

    Midniteoyl

    Midniteoyl

    Midniteoyl

    Well-Known Member

    Joined:
    Sep 4, 2003
    Messages:
    2,417
    Likes Received:
    500
    Location:
    Indiana
    Something else pretty cool..


     
    Last edited by a moderator: Mar 20, 2019
    Little Scrapper likes this.
  10. Feb 9, 2016 #50

    Little Scrapper

    Little Scrapper

    Little Scrapper

    Well-Known Member HBA Supporter

    Joined:
    Jan 3, 2014
    Messages:
    5,249
    Likes Received:
    3,153
    Location:
    Wisconsin
    Suppose I'll have to order that too Jim. Lol
     
    Midniteoyl likes this.
  11. Feb 9, 2016 #51

    ekimneirbo

    ekimneirbo

    ekimneirbo

    Banned

    Joined:
    Oct 31, 2014
    Messages:
    1,009
    Likes Received:
    324
    Location:
    Deep South
    Just have a question...are you sure you meant to say .020 shims instead of .002 shims?
     
  12. Feb 9, 2016 #52

    Midniteoyl

    Midniteoyl

    Midniteoyl

    Well-Known Member

    Joined:
    Sep 4, 2003
    Messages:
    2,417
    Likes Received:
    500
    Location:
    Indiana
    Pretty sure it would be .020 shims as the Johnson is only accurate to the 10th..
     
  13. Feb 9, 2016 #53

    Little Scrapper

    Little Scrapper

    Little Scrapper

    Well-Known Member HBA Supporter

    Joined:
    Jan 3, 2014
    Messages:
    5,249
    Likes Received:
    3,153
    Location:
    Wisconsin
    Well, in 48" long at .1 degrees the rise should be about .080" at a 90 degree angle . That's just in my head, but that's about right.
     
  14. Feb 9, 2016 #54

    Little Scrapper

    Little Scrapper

    Little Scrapper

    Well-Known Member HBA Supporter

    Joined:
    Jan 3, 2014
    Messages:
    5,249
    Likes Received:
    3,153
    Location:
    Wisconsin
    Yeah, .0838" rise in 48" assuming a 90° right triangle which it was. Either way, I can't trust a level that doesn't zero out.
     
  15. Feb 9, 2016 #55

    ekimneirbo

    ekimneirbo

    ekimneirbo

    Banned

    Joined:
    Oct 31, 2014
    Messages:
    1,009
    Likes Received:
    324
    Location:
    Deep South
    [/QUOTE] My trig is a little rusty but a quick compute shows that a 48" radius would need about .084 or almost 3/32 (.0935) to make a 1/10 degree angle movement. So about four .020 shims should get close to showing on the dial...and five shims should push it to the point of getting a reading. While 1/10 of a degree sounds precise, when you look at 3/32 of error over a 48" span it doesn't seem as close. Of course thats if my quick(?) calculation was right. Another way to look at it would be appx .002 per inch (.00175) If you set a level in the middle of a 16' board and had a reading of 1/10 degree on the dial...the difference from one end of the board to the other could be .336 (almost 3/8) to .671 (about 11/16). You have to remember that once you are reading 1/10 that you could be anywhere between 1/10 and just below 2/10 because it operates in steps rather than linear readings. If someone does manage to keep their readout below the 1/10 degree reading then they still have anything between perfect and .336 from one end to the other of a jig table. Thats why I think a water level is best for establishing the overall level point for a table. It will give exact level indication and the only variation is if its marked properly by the builder. Then once you are working from a level surface, the lazer level should help keep the surface mounted on it .....flat.

    Dang, all this figurin is makin my head hurt.........hope I got it right:) (apparently I was doing this at the same time as LS was doing his calc)

    Prsonally I think we are asking something from these levels that is really beyond what they are intended to do. They can probably make the digital readouts to even greater accuracy, but then it would become very difficult for construction workers to get meaningful information. If they read to the next greater decimal place they would be so "touchy" as to become useless...so I don't think its inaccuracy that is the problem rather than trying to make them accurate enough for easy use on the job. Let me suggest a test for all builders to see just how accurate their levels are. You would need a lazer level to do this. Set up a water level. Then set your lazer level
    right next to it with the lazer beam at the same height as the water in tube at one end. Adjust or shim your lazer level until the lazer beam is hitting the water in the water level that is at the far end....then see what the digital reading on the lazer level is. Thats a pretty simple way to check your accuracy over a distance.
     
    Last edited: Feb 9, 2016
  16. Feb 9, 2016 #56

    Little Scrapper

    Little Scrapper

    Little Scrapper

    Well-Known Member HBA Supporter

    Joined:
    Jan 3, 2014
    Messages:
    5,249
    Likes Received:
    3,153
    Location:
    Wisconsin
    I just love Amazon Prime. Received the level, well packaged. I'm still playing with it and I'll report back but I'll tell you thing is truly amazing. Absolutely built like a tank. There's no way these box store levels even come close to this Stabila. Thanks for the link Jim, money well spent.
     
    Midniteoyl and ekimneirbo like this.
  17. Feb 9, 2016 #57

    Pops

    Pops

    Pops

    Well-Known Member

    Joined:
    Jan 1, 2013
    Messages:
    6,683
    Likes Received:
    5,572
    Location:
    USA.
    Back in another life when I was young, I worked as a high rigger setting building steel, Stacks, TV/Radio towers up to 1268'. Everything was set using a water level.
     
  18. Feb 9, 2016 #58

    Little Scrapper

    Little Scrapper

    Little Scrapper

    Well-Known Member HBA Supporter

    Joined:
    Jan 3, 2014
    Messages:
    5,249
    Likes Received:
    3,153
    Location:
    Wisconsin
    It has a spirit level in it.

    Just got off the phone with a customer of mine who manages a surface grinding company that makes machine ways for lamb research who makes machine tools for the big 3 etc. He told me to come on down an set it on his testing slab. So that's where I'm headed. I'll report back this evening.
     
    Midniteoyl likes this.
  19. Feb 10, 2016 #59

    Little Scrapper

    Little Scrapper

    Little Scrapper

    Well-Known Member HBA Supporter

    Joined:
    Jan 3, 2014
    Messages:
    5,249
    Likes Received:
    3,153
    Location:
    Wisconsin
    Ok. So the manager met me at the machine shop and fortunately a young machinist with some really wicked tools decided to hang out with us before going home and we borrowed his tools. A couple things I learned about this.....

    It's easy to get caught up in to numbers game because the Stabila level itself has graduations that measure .01 degrees at a time, definitely fine from a builders perspective but when comparing against real machinist tools hardly accurate at all. The first thing we did was set it on a very flat surface plate that's insanely accurate and checked for accuracy frequently given the nature of the business they are in.

    I learned that machinists have various types of tools in which to measure angles, I was quite surprised really, very interesting tools them guys use. Anyhow, we zeroed or calibrated the level on the plate and set it to zero degrees. Once that was done the "Brad" the young machinist, decided it was smart to take off the 2 rubber ends on each end of the level so the level was measured on just the aluminum extrusion itself. We then put the level on a massive steel adjustable angle thing that measure about 12" X 12" square. He set it by eye than put a machinist level on it and dialed it in. He said his machinist level was accurate to .0005" , or 1/2 a thousandth in 1 foot. The machinist level I would say was less than 20". Regardless, the angle plate thing he set at exactly 10 degrees and when the stabila level was put on it is registered at exactly at 10 degrees. So far so good.

    We then shut the level off, shook it, twirled it, and checked it again. Exactly 10 degrees.

    We then left the level on and shook it, twirled it, and checked it again. Exactly 10 degrees.

    Interestingly, when we set the angle at at exactly 45 degrees the Stabila was off by .05 degrees, bounced to .00 and then settled at .05 degree. We went back to the surface plate and checked it again, dead nuts at zero degrees. We did a few other things and basically came to the conclusion the anything under 30 degrees from level or plumb the Stabila is absolutely dead nuts accurate. but for some reason right around the 45 degree mark it tends to be off a hair. This really means nothing to me because .05 degree on a 45 is irrelevant to what we are dong with airplanes.

    Everything above is pretty irrelevant though because in a shop like you and I have to build these airplanes in we simply don't have access to an accurate surface plate. So I guess the real test is NOT on a surface plate but rather buy eye, so that's what I did. In the machine shop Brad had his tool box shut so I set it on top and shimmed it by eye until the spirit vial was level or at least according to my eye it seemed level. Once I was happy I zeroed the level and calibrated it from the bubble. Brad then took his machinist level and set it on top of the Stabila. I was really shocked, blown away actually, just by eye I was able to level the bubble to dam near .010". I would say his tool box that I set my level on was about 30" long as far as the surface is concerned.

    Here is what I learned. First of all I love the level, the build quality is typical of the Germans, solid as a rock. Second, there's no need for a digital level if you just need things level and plumb because the naked eye...assuming you have a very good quality spirit level, is freakishly accurate. I can literally calibrate the level by eye and be confident it's level. I'm glad I bought the digital level because I can set angles with it.

    The Stabila level I bought has all sorts of features that I probably will never use. I do like how well the back lighting works and how you can read the numbers form the side or the top.

    So that's that. I love it!

    Scrap
     
    Topaz, Midniteoyl, ekimneirbo and 2 others like this.
  20. Feb 10, 2016 #60

    Little Scrapper

    Little Scrapper

    Little Scrapper

    Well-Known Member HBA Supporter

    Joined:
    Jan 3, 2014
    Messages:
    5,249
    Likes Received:
    3,153
    Location:
    Wisconsin

Share This Page

arrow_white