Weems and Plath Endurance 125 Clock - Manual (Page 4)

6. Remove the mounting plate and drill the wall marks with a 3/32" or
2.00mm drill bit.
7. The mounting plate is designed with stepped mounting holes. The
smaller diameter facilitates accurate hole marking and avoids the
errors inherent in measuring or the use of a separate printed template.
The larger diameter is to receive the diameter of the screw thread.
8. As the screws are driven tight, the thin plastic forming the smaller
diameter hole will give way around the screw thread and form a tight
assembly.
9. Weems & Plath advises that on some wall materials such as
fiberglass, it is possible that the material around the drilled hole can
swell and displace forwards causing a volcano ridge around the
screw. This ridge will prevent the mounting plate from being screwed
tight to the wall. It is recommended after drilling the 4 holes that they be
countersunk creating a space to absorb any material displacement.
10. Secure the mounting plate in place with four No.8 round head stainless
steel Phillips screws supplied. These screws will displace the thin
plastic in the holes as they are driven home. Ensure the screws are
tight and the plate is firmly flat against the wall.
11. Place the instrument's back side above the mounting plate and position
on the vertical center line about ¾" (20.00mm) above the horizontal
center line and slide downwards to engage the dovetails.