attached to the LASER_PLATE using three spring-loaded
screws. This creates a ‘three-point floating mount’ for the
This floating mount approach provides for easy laser
adjustment, using just two of the three spring-loaded
screws. With these screws, one can easily align the laser
beam and compensate for any laser, lens, fabrication, or
tolerance stack-up errors.
I frequently mill out first time parts in plastic as it’s
easier to machine and more forgiving to my mill bits
if I make a mistake in the G-code. To this end, I
made the LASER_COLLAR from .375 thick HDPE
(high density polyethylene) plastic sheet that I had
on hand thinking I would make the “final part” from
However, I found the plastic part worked just
fine as-is. Feel free to substitute aluminum or almost
any other strong plastic for the part. Just bear in
mind that the LASER_COLLAR must endure the
centripetal load of the mass of the laser during
spindle rotation. As such, don’t use brittle or weak
materials for this part as you don’t want it to break
or shatter while the device is rotating!
The laser mounting hole in the LASER_COLLAR
must be drilled at a 10 degree angle from vertical.
To perform this operation, I clamped the part in a
small mill vise and then stuffed shim blocks under
one side of it until I had the vise (and part) tilted 10
degrees. I then used clamps to secure the vise to
the drill/mill table so it would remain stable
throughout the drilling process.
The total height of the shim blocks needed
depends on the size of the vise. You can use a
protractor or calculate the shim height using the
40 SERVO 07/08.2018
Figure 8. Top view of completed assembly.
Figure 7. Assembly guide for
Figure 9. Bottom view of finished assembly. Tie wraps
are required to hold batteries in place.