shop safety rules apply when the rotating alignment device
is mounted and running in your machinery. I would add the
recommendation that the rotating center finder device be
carefully inspected prior to each use.
Also, be sure the battery cable ties are in place and
that there are no loose screws or other parts that could fly
off the device as it rotates. I added cable ties around the
battery holders after seeing a battery loosen up and
become a flying projectile! Don’t let this happen to you!
Along these same lines, I strongly recommend that the
rotating alignment device only be used in variable speed
machines, and then only at speeds less than 1,000 RPM.
Do not use in DRILL PRESSES or ROUTERS if slow
speed start-up and low speed operation is not
Even the relatively low power 5 mw RED laser used in
this project is able to produce extremely bright, tightly
focused, high energy beams of light. Such light can damage
DO NOT STARE DIRECTLY INTO THE LASER BEAM
AT ANY TIME!!
Also note that the basic geometry of the rotating
alignment device can result in VERY BRIGHT reflections of
light. This is especially evident when the laser circle is small
or has converged to a single point. Use caution when laser
centering on highly polished or reflective surfaces as the
reflected light can be very intense!
Rotating Alignment and Setup
Rotating center finder alignment and setup is easy.
Here are the steps:
1. Inspect the device to be sure all of the hardware is
tightened. Make sure the battery tie wraps are in place.
2. Start by setting all alignment adjusting screws so
that the three-point LASER_COLLAR is spaced about 1/4
inch from the surface of the LASER_PLATE. Turn each of
the three spring-loaded screws until the COLLAR is visually
parallel with the LASER_PLATE.
3. Unthread and remove the focus lens mount from the
laser. Place a wrap of plumber’s Teflon tape around the
threads and reassemble. Check the laser lens to be sure
that it’s threaded into the laser far enough so as not to be
loose, ‘wobbly,’ or prone to come out. Don’t worry about
focus yet; this will be checked and set later.
4. Mount the alignment device into the machine collet
and turn the laser on. You will see the laser dot on the
stage of the mill. As you manually turn the spindle, you’ll
see a circular path traced out on the work surface.
5. With SAFETY GLASS ON, turn on and slowly ramp
up the spindle speed. You’ll see the rotating dot become a
circle. Keep the RPMs low until you are confident that
nothing is loose or severely out of balance.
6. Now begin moving just the Z axis of your mill/drill.
You should see the diameter of the circle grow and shrink as
you move the Z axis up and down. While the circle size will
vary, it will probably not shrink to a single point just yet.
7. Move the Z axis until the circle is as small as it can get.
Stop the spindle rotation. With the initial setup
completed, fine adjustment is now possible. I found that
placing and targeting a 1/4 in ID washer on the machine X-Y table is a useful assist for making the following fine
8. STOP THE SPINDLE ROTATION.
9. Now, turn each of the two adjustment screws
accessible from the bottom of the alignment device while
it’s still in the mill. By turning these two adjustment screws,
the dot will move.
10. Using the adjusting screws, move the dot as close
as you can to the center of the washer target.
11. Manually turn the spindle and observe the motion
of the dot; stop periodically to try slightly different
centering screw adjustments.
12. At this point, you can also focus the beam by
rotating the laser FOCUS RING until the spot is as small and
well-focused as possible.
13. SLOWLY ramp up the spindle speed; you’ll probably
see a circle that is smaller and better focused that you had
14. Move the Z axis until you find the smallest circle
possible and repeat steps 8-13. You are done when you see
a single stationary dot.
Once adjustment is complete, you can apply some
Loctite to the adjusting screws if needed to help hold the
adjustments in place.
At this point, it should be possible to put the device
into and out of your machine without need for
realignment. However, a drop or jar of the assembly can
throw things off.
A Few Diagnostics
One of the intrinsic things about this spindle mounted
design is that even when the device is in need of some fine-tuning, it remains accurate and useful as long as the
feature you are targeting is larger than the smallest circle
spot you can trace. Here are some diagnostic tips to
optimize your build:
42 SERVO 07/08.2018