WEAR YOUR
FORESIGHT IS BETTER
THAN NO SIGHT
READ INSTRUCTIONS
BEFORE OPERATING
SAFETY GLASSES
SHERLINE PRODUCTS INC.
•
3235 Executive Ridge
•
Vista
•
California 92081-8527
•
FAX: (760) 727-7857
Toll Free Order Line: (800) 541-0735
•
International/Local/Tech. Assistance: (760) 727-5857
•
Internet: www.sherline.com
9/8/21
SHERLINE/WETTROTH
Mill Digital Readout
P/N 8100 (Metric P/N 8160)
The Digital Readout in the Modern Machine Shop
Digital readouts are popular on full-size mills because
they make the life of a machinist much simpler. They
make it easier to accurately set or change the table position
and eliminate errors caused by misreading handwheel
increments or losing track of multiple rotations. Now that
same convenience is available on tabletop size machines
with a DRO (Digital ReadOut) for Sherline mills. John
Wettroth designed the compact electronics package and
clever backlash compensation feature.
On industrial DROs, a sensor reads a highly accurate external
scale. On Sherline’s DRO, the sensor reads rotation of the
leadscrew. Because of the accuracy of Sherline’s precision
rolled leadscrew threads and the short travels on a machine
of this size, this system makes it possible to provide a
DRO with sufficient accuracy while maintaining a price
appropriate for a machine of this size and cost.
The kit can be installed on any Sherline mill, regardless of
age and is very easy to use. Remember that the directions
of movement of the mill are referred to as the X-axis (table
side-to-side), Y-axis (table in-out) and Z-axis (spindle up-
down). The readout of any axis can be set to zero at any
time with the push of a button. As you move the handwheels
you can read the table position to three and a half decimal
places on the digital readout. It is not necessary to keep
track of the number of handwheel rotations to figure the
stopping point on larger dimensions. This will be especially
appreciated when cranking in “negative” amounts. Backlash
is compensated for by setting it into the unit’s electronic
memory in increments of .0005". As a bonus, the package
also includes an electronic readout of spindle RPM at
all times.
NOTE:
The DRO unit itself is accurate to within 1/100 of a
revolution of the screw.
Example:
On our 3/8-20 leadscrew,
the pitch is .050/rev.; therefore, .050/100 = .0005". The
accuracy on a 10 x 1mm leadscrew will be .01mm. On our
10 x 2mm ball screw, the accuracy will be .02mm.
Installing the DRO Components on Your Sherline Mill
The following instructions describe the steps required to
remove the existing handwheels and thrust collars and
replace them with the DRO encoder/handwheel units.
It
is suggested that you remove the headstock and motor
assembly from the mill to make it easier to install the DRO
components. (“Left” and “Right” refer to the operator’s
left and right sides when facing the mill with the X-axis
handwheel on your right.)
1. Move the table all the way to the left. This will limit
movement of the leadscrew and help center the new
collar.
2. Move the table all the way to the front toward the
operator.
3. Raise the headstock all the way to the top of its travel.
4. Using a 3/32" hex wrench, remove all three handwheels
by releasing their set screws and sliding them off
their leadscrews. (If your mill has resettable “zero”
handwheels, loosen the collar locking knob and rotate
the collar until the hole lines up with the set screw. Then
use the 3/32" hex wrench to loosen the set screw and
remove the entire handwheel/collar unit.)
5. Using a 3/32" hex wrench, remove the 5-40 screws
holding the thrust collars on the X- and Y-axis
leadscrews. Remove the collars.
6. Clean each grooved thrust collar with a solvent like
acetone or lacquer thinner to remove any oil from the
surface. (You will later lock them in place in relation
to the plastic housing with "instant glue" and it will
not stick to an oily collar.) Using the existing screws,
install new grooved thrust collars on the X- and
FIGURE 1—Installing the
new thrust collar on the
X- and Y-axes
New Collar
Existing Screw
Leadscrew Shoulder
Leadscrew
