Sherline Laser Aligner Realignment

With the Sherline CNC mill once again able to move under its own power, an hour or so of tweakage got the laser aligner settled in its new home:

It’s (still) an upcycled laser line projector, minus the cylindrical lens stretching the dot into a line, running from a pair of AA alkaline cells:

The three small screws provide simpleminded angle adjustment, with the disadvantage of simultaneously moving the lens in the XY plane.

The upper bubble level shows it’s not at all vertical:

That’s because the beam must fall down the middle of the Sherline’s spindle bore:

Getting the alignment right requires a mirror on the tooling plate, which I will not attempt to photograph again, reflecting the beam upward through the spindle, where it will light up the bottom of the no-longer-a-line projector’s lens mount. When that happens, the projector is boresighted on the spindle, regardless of whether the tooling plate is perpendicular to the local gravitational field.

With the Z axis / spindle near the top of its travel, screwing the lens (mounted in a toolholder) onto the spindle produces a defocused beam on the tooling plate:

If the spot doesn’t look similarly round-ish, then the beam isn’t completely filling the entrance pupil of the lens and you must twiddle the projector’s angle / position until it does.

With that done, running the Z axis to put the lens about 30 mm above the plate produces a suitably teeny spot:

The Sherline’s previous home atop that same gray countertop had been firmly affixed to the basement wall, with the gantry and laser projector screwed to the floor joists: everything immovable. The countertop now sits atop a workbench not firmly affixed to anything: a good solid bump will likely knock the Sherline out of alignment with the beam.

How often that happens and how awful recovery will be remains to be seen. For now, It Just Works™ again.

Feeding Sherline aligner into the search box will reveal much of the backstory.

I extracted an XZ positioner from the Box o’ Optics Lab Stuff before coming to my senses: this is not nearly such a critical application.