A simple tool helping to get the Ultimaker sliding blocks well aligned.Nothing revolutionary here, but this method help me to get a better tuning of the machine.1 - Clip two of them(one at each side of the head) on the same axis (Y OR X) 2 - Check using the frame edge if both tools reach the frame edge, if not, your sliding blocks need some adjustment. 3 - In that case, loosen the pulleys on the side you want to adjust the sliding block position, then move backward or forward the block until the axis tool on the misaligned side, finally reach the frame edge.Note : Depending on where the screws on your pulleys are placed, you might not be able to reach them to loosen the pulleys. If so, try the opposite frame edge by rotating both tools on the axis and check if the pulleys screws are reachable. You may also reduce the length of the tools to fit your needs or even put a reference mark on both axis tools, once you managed to have the pulleys screws accessible. Edit : I have uploaded the SKP file so you can easily change it in sketchup ! (I know that this tool could be shorter !)