Build Instructions

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• 1

  Manufacturing and building instructions

  Manufacturing Parts

  The entire machine is made of aluminum plates and profiles with drilled holes, with no complex parts requiring machine tools like a milling machine or lathe. All components can be ordered pre-cut to size and drilled with the tools you have available.

  For positioning the drill holes, I used traditional methods with a compass, a graduated ruler, a square, and carbide scribers. A reference edge and origin point are chosen, and axes are marked out from this point.

  Precision is important but manageable. When drilling, I typically add 0.5mm to the bolt diameter (e.g., M6 = 6.5mm) and aim for at least 0.5mm accuracy when marking.

  Once marked, the drill hole locations are center-punched.

  The countersinking for bolts is done using countersinking tools. For M8 bolt countersinks, a good drill and ideally a drill press are required.

  Assembly and Adjustment

  I drill the screw passages for the rails and bearing blocks at the last stage, using a dial gauge to ensure the rails are perfectly parallel.

  The principle is straightforward: I drill and mount the first rail parallel to one side of the frame, clamp the second rail, and ensure it is parallel to the first using a dial gauge. Once the position is perfect, I center-punch the locations with an adjusted-diameter carbide scribe.

  The rest of the assembly is straightforward. Once the machine is assembled, it needs to be adjusted.

• 2

  Fine adjustment of geometry

  Fine-tuning is crucial as it determines the precision of machining geometry.

  It also impacts surface finish quality, noise, and the lifespan of cutting tools.

  Adjustment with shims or by rotation

  Connections between two elements typically involve planar contact with screws. There are two types of adjustments: rotation of parts by pivoting them against each other and the use of shims.

  Shims can be a nightmare if you don’t have a set of sheets with different thicknesses. That’s why I favored rotational adjustments during the design phase.

  Degrees of freedom

  I define a degree of freedom as the possibility of rotational adjustment around an axis. The ideal structure minimizes the degrees of freedom and reduces the number of parts.

  It’s also important that adjustments follow the machining XYZ coordinate system. Moreover, it’s far more practical for an adjustment to affect only one axis. If a rotational adjustment affects two axes, the process becomes more complex and time-consuming.

  On this milling machine, there are four degrees of freedom:

  • Perpendicularity of the X and Y axes
  • Perpendicularity of the X and Z axes
  • Perpendicularity of the Y and Z axes
  • Coaxiality of the Z-axis with the spindle axis

  Tooling

  I use a dial indicator with a magnetic base and a DIY dial indicator holder. You can make your own; it doesn’t require precision.

  Adjustment process

  • Red: screws to tighten/loosen. Always remember to work in rotation; one screw should always be tighter than the others.
  • Yellow: the movement to apply. The movement should be as long as possible with minimal dial indicator displacement. Less than 0.05 over 50–100 mm provides excellent precision.
  • Green: control points.

  1. Place a precision square on the table and adjust its position so one edge is // to the X-axis.

  2. Move the dial indicator along the Y-axis and adjust the Y-axis. => The X-axis is now perpendicular to the Y-axis.

  3. Materialize the spindle’s Z-axis by inserting a pin or drill bit. Check the spindle’s concentricity (it’s not always perfect).

  4. Adjust the // between the spindle axis and the Z-axis rails. => The Z-axis rails are now // to the spindle’s Z-axis.

  5. In the final step, the perpendicularity of the X and Z axes relative to Z is adjusted simultaneously. Mount the dial indicator holder in the spindle. => The machine is now perfectly aligned along all axes.
     

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