book collections email follower instructable user
Picture of 3D Printer Bed Leveling Assistance Tool

Hello everyone and welcome to my fifth instructable!

A correctly leveled 3D printer bed is essential to ensure successful and accurate prints.

There are two main ways to get a well calibrated print plate: auto-level systems or manual leveling.

My printer does not have an implemented auto-level and, for various reasons, I do not feel the need to have it. So I always go for manual bed leveling.

The most common way to do it is to move a piece of paper under the nozzle and adjust bed height until you "feel" the correct amount of friction. As you can imagine, the results are quite imprecise, especially if you are a new user. The use of a feeler gauge blade certainly makes it more precise but there is always the "touch sensitivity" variable.

That is why I thought to build a tool to assist me in this important operation. The concept is very simple: a LED circuit that uses, as a switch, the touch of the nozzle on a known thickness element (a feeler gauge blade).

This simple tool will give you exact and repeatable results.

Step 1: Materials and Tools

Picture of Materials and Tools


  • 3V coin cell battery
  • LED
  • Very thin and flexible wire
  • Crocodile clip
  • Flat magnet
  • Plastic bottle cap
  • Cigarette filter
  • Double sided adhesive tape
  • Glue
  • Heat shrinking tube or electrical tape


  • Feeler gauge with removable blades
  • Cutter knife
  • Scissors
  • Soldering iron
  • Soldering tin
Drmartin23542 months ago
Would this be available for purchase?
CliffordS5 months ago
Note that LED are not light bulbs and require a series resistor to drive them correctly. Without that, the LED may not last long and the battery certainly won't, and it will be unnecessarily bright. For a typical red LED, a minimum 50Ohm series resistor would be required for a 3V supply. See If you use an AA 1.2V rechargable or a 1.5V regular cell, then you may not need a resistor if the battery voltage is less than the LED forward voltage. If you don't know the LED specs, best use a series resistor in any case. Since you need not run it at max brightness, a larger resistor will not hurt - say 100Ohm to be safe. Or just use a traditional filament bulb.

An interesting alternative is to use a self-drive piezo sounder/buzzer. Then you can concentrate on sighting the adjustment rather then watching the light, and no drive issues - just direct to the battery. Example: Make sure you get one with a drive, not just the piezo element.
gibetto (author)  CliffordS5 months ago
Considering that the LED will be on for a very short time, I decided to simplify everything as much as possible. However you are absolutely right, I will surely add a resistor to make a correct circuit.
Thank you for the valuable informations and for the good idea about the piezo sounder/buzzer.
A resistor is not required when using button cell batteries like the 2032. There is enough internal resistance in the battery itself.
Typically 10 Ohms according to I'd say that was still too low, and an additional 40 Ohms at least would perhaps be advised. But granted I was not aware that Lithium cells had such high IR.
MTKapp275 months ago
Interesting solution. I don't know why you think automated bed leveling isn't needed. It solves a majority of issues and takes away most of the maintenance work needed. Prusa has automated bed leveling for more than one plane too.
Manual adjustment has its place. Funny you mention Prusa. My friend has one and had to modify it so he could manually adjust the bed level. The bed was so far off there was a part of his bed he couldn't use because things wouldn't stick. The best solution isn't a manual then auto approach, it's auto bed leveling. As in 3 Z motors and the bed is actually leveled by the printer, not just accounted for with a Z offset in different regions. Look up the Railcore printer, it does this and it's brilliant (coreXY, linear rails, auto mechanical bed leveling. It's basically my dream printer).

By the way, this leveling probe is a great idea. I'm going to have to make one.
gibetto (author)  MTKapp275 months ago
Let's say that I don't like very much the approach of auto-level systems which consists in adapting to an error by continuously moving the Z axis motors (with related problems), instead of solving it. But they really have many advantages like the ones you mention.
Probably the perfect solution would be a combination of both: leveling the plate as best as possible by hand and letting the auto-level work for the remaining micro-errors.
MTKapp27 gibetto5 months ago
The approach isn't "adapting", but rather that solution is software driven. It assumes the printer is already aligned as best as possible.I don't understand how you can think hand leveling is superior at any level. Prusa is also equipped with a number of sensor which are more accurate/precise that any hand leveling possible. You can argue the hand leveling is done during the initial calibration so you perfect solution is basically already implemented.
gibetto (author)  MTKapp275 months ago
I start saying that these are just my personal opinions.
We want the nozzle tip to be at the same distance from the bed in every point of the plan. If there is a misalignment of the bed, we can operate in two ways: moving the nozzle "adapting" to it (what auto-level does, by adjust Z height) or correcting the error by aligning our plane (what we manually do).
The software assumes that all is already aligned. If it was true, you would have the perfect solution I was talking about because the only aim of the auto-level system would be to adapt to micro-errors or potential dips, if any. Actually this would imply double work: a manual leveling because we know that the plan loses its regulation (for various reasons, first of all the not perfectly rigid structure, especially with acrylic frame like mine) and the software work.
But this would nullify the main purpose of auto-level which is to avoid having to adjust the bed manually and let the software adapt to a misaligned bed.
In my opinion a right software-guided approach would be to probe the points, build a "map", calculate misalignment and then adjust the height of the bed (basically the manual work but with more precision). There are some systems that work like that but they add many components and therefore complexity and costs, so it's not worth it.
I could go on with many other considerations regarding the addition of various sensors related to: costs, reliability, addition of weight (despite minimal) to the trolley, adjustment of the sensor itself, etc. All for not adjusting 4 (or 3, depends on the configuration) screws occasionally.
webliya made it!5 months ago
I made one but unfortunately because of filament residue at the tip of nozzle it does not work properly.
gibetto (author)  webliya5 months ago
Try to wipe the tip of the nozzle with a brass brush, then it should work properly.
In alternative, if you don't have the brush, try to heat it up to a temperature slightly below extrusion one and, taking care not to burn yourself, pass some folded (to provide extra strenght) paper towel on it.
Let me know ihow it goes.
webliya gibetto5 months ago
Thanks. Brushing sure works.
briandamge5 months ago
I like it, great job!
gibetto (author)  briandamge5 months ago
Thank you!
I think this would be a perfect solution for finding the z offset of your printer. When using an inductive or similar sensor for the Z limit switch it will trigger when the nozzle is still above the bed surface. Finding out this distance will determine the Z offset that you need. Using the method described in this instructable would work nicely! You would slowly lower the Z access until the light came on. The amount you lower + the feeler gauge thickness would be your Z offset. However it is best to measure the Z offset when both the bed and nozzle have been heated to their working temperature. This is because you will find that the Z offset distance will change with the change in temperature. Great idea, Thank You!
gibetto (author)  makerhangout.contact5 months ago
You are right, this method should work fine. Thank you for adding value to this project!
Chafftastic5 months ago
Simple and very effective.
gibetto (author)  Chafftastic5 months ago
Thank you!
cobourgdave5 months ago
Regardless of the criticism, you have a neat and simple approach to manually levelling the bed. Good thinking! Keep developing your idea
gibetto (author)  cobourgdave5 months ago
Thank you!
hubi5 months ago
I see a problem wit this method. The blade does never lie on the Bed really flat. Also the Nozzle is often coated with Filament residues of the last print, esp. when using PETG, so it is not conducting. I had bonded some thin aluminum foil in all 4 corners of the bed for contact to the Nozzle but had often issues with non leading becuase of thin residues at th etip of the nozzle, so i now use a cheap capacitive sensor.
gibetto (author)  hubi5 months ago
I have experienced both problems at the beginning but, with this version, I consider them solved: the blade lifting by using an extremely thin and flexible wire which is too "weak" to cause this issue; the non-conducting nozzle tip by simply wiping it with a cheap brass brush.
I also considered the aluminium foil solution and it sounds good but you should know its exact thickness.
TimothyM1165 months ago
So simple, but so brilliant the same. You gave me a good idea to get rid of my bed leveling problems.

Thank you. You'll definitely have my vote. Ottimo lavoro davvero.
gibetto (author)  TimothyM1165 months ago
Thank you very much for the comment! Grazie mille!