Sherline Laser Alignment: Aligning the Laser

Laser spot entering spindle bore
Laser spot entering spindle bore

This is a better view of the alignment process that I endure once a year when I haul my Sherline mill back from Cabin Fever. The whole thing depends on a laser level that I’ve gutted and clamped to the floor joists over the mill, as described there.

The first step uses a plumb bob to position the hacked laser level lens directly over the Sherline’s spindle bore. I’ve shimmed the countertop under the mill to be pretty much level, so a vertical line from the bore determines where the lens must be.

Then I fiddle around to get the beam directly in the middle of the spindle bore, using a slip of paper to figure out where it’s going. The top picture shows the result.

Having done this a few times, the laser level starts out pretty much aligned, but the first setup required quite a bit of back-and-forth twiddling of the screws.

Then I put a mirror flat on the Sherline’s table / tooling plate to reflect the beam back up the spindle. More fiddling around gets the reflected spot pretty close to the outgoing beam; this picture shows the spot just off-center near the top (actually, toward the base of the laser level’s frame) of the aperture.

Reflected spot near laser aperture
Reflected spot near laser aperture

When the outgoing and reflected beams converge, then I put the bushing (without the polarizing filter) in the top of the spindle bore to reduce the beam size and fine-tune the positions & angles.

Surprisingly, it stays in position quite solidly. I do twiddle it every now & again, but as long as the beam gets through the bore it’s close enough.