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When building a reprap, certain issues arise that may not be covered in the rest of the Wiki. Here, we will attempt to gather some of the lessons learned that don't really fall within other pages.


Prints shrink very slightly when cool. It's important to take this into account when calibrating your X and Y movements.

Electrical Wiring

NEVER plug or unplug things from your control board while it is powered up. NEVER!! Stepper motor drivers can be destroyed if the motor is disconnected while powered. Make sure wiring is secured so that movement of the printer does not stress the connections or catch on the wires. Be careful not to run the stepper motor wires near other signal carrying wires, like end-stop wires as interference can trigger the endstop [1].


-Before upgrading the firmware on your control board, be sure to know what your current settings are in your Config.h. You must reenter these setting manually in the new firmware's Config.h to prevent compatibility issues.

-If you are building a new printer, note that the settings in the firmware you choose - for speeds, acceleration, jerk etc. are usually set for a high-end printer, but usually not your printer. It is best if you can get a copy of the configuration.h from another user with your type of printer, or a similar printer as a starting point. Otherwise you should reduce the speeds and acceleration in firmware to a much lower number (1/2 or less), and increase them after your initial calibration is done.



Lithium grease makes a good lubricant for printed bushings.

Quick Zip-Tie Belt Tightening Method

-If your belts are a bit loose and removing gears and/or belt clamps becomes a time consuming task, use this method: Using 3 small zip ties, loosely loop 2 of them around the belt you wish to tighten and zip them just enough to catch. Use the third zip tie and run it inside both of the other two. Again loosely zip it. Now, return to the two around the belt. Tighten them about 2-3cm apart firmly. You should have the one loose tie remaining that is looped through the other two. Ensure all the slack is on the side of the pulley that you are trying to tighten and slowly tighten the last zip tie until it is firmly in place and pulling the other two together. Clip the ends and enjoy your nice tight belts.--MrJohn 23:20, 9 April 2011 (UTC) (Thingiverse link removed - object did not exist 12/27/15 Paul Wanamaker)

Cutting Metal Rods

The easiest way to cut the metal rods is with a chop saw/cut off saw made for cutting metal. The saw will need an abrasive disk blade. Harbor Freight sells one of these saws for $30-$50.

Use a Z Probe

A Z Probe will allow you to set your z height with a very high degree of accuracy. This will save you a great deal of time and frustration in the long run.


-To make the reprap quieter, there are some possibilities:

1. The current adjustment pots on the stepper drivers should be set just high enough that no steps are lost. However, if the current is set too high then the stepper motors make a harsher, louder sound. If the current is too high then the stepper drivers will overheat leading to lost steps and shifted layers [2] and the motors could overheat.

2. A thick blanket over the top, good rubber feet, printed isolation feet or sorbothane [3] feet underneath the printer can work to reduce the vibrations on the table.

3. All screws should be tight, loose screws vibrate.

4. Enclose the printer by either adding panels to the outside or enclosing it in a box with an acrylic or polycarbonate door. The box could be made out of rigid foam panels if you want to retain some heat. Plan carefully to properly cool your electronics if it will be inside a heated enclosure.

5. If you are using large, high torque motors (Nema-23 for example) then you may want to use external DSP based stepper motor drivers [4]. These can be tuned to reduce mid-band resonance, and can make the printer much quieter.