Challenge CMT-130, Service Manual, Page: 82 / 226

FEB 2017
3. Book Quality 3-2 CMT 130 Book Trimmer
BQ 3.1 Burr Marks
Description
Burr marks are found on books cut with a knife
where the cutting edge has been burred. Figure
3-1 illustrates the appearance of burr marks.
Figure 3-1. Burr Marks
Possible Causes

Burrs on knife can occur from improper
knife handling.

Burrs may also occur from cutting hard,
irregular materials.
Solutions

Replace the knife (REP 4.2 Knife Re-
placement).
BQ 3.2 Jagged Bottom Cover
Description
Books can appear as though the bottom few
sheets and cover were torn apart rather than
sharply cut. Tearing of the bottom sheets and
cover occur when deep score marks develop in
the cut stick. The cover is pushed into the score
mark, folded over and torn.
Figure 3-2. Jagged Cover
Possible Causes

The knife may be dull.

The cut stick may be worn.
Solutions

Rotate or replace the cut stick (REP 4.1
Cut Stick Replacement).

Replace the knife (REP 4.2 Knife Re-
placement).
BQ 3.3 Burr Marks/Jagged Cover
Description
A jagged bottom cover may also accompany
burr marks. A burred knife may not fully cut into
the cut stick. As a result, it will leave a jaggedly
cut bottom cover.
Figure 3-3. Burr Marks/Jagged Cover
Possible Causes

The knife is burred, and the cut stick is
worn.
Solutions

Rotate or replace the cut stick (REP 4.1
Cut Stick Replacement).

Replace the knife (REP 4.2 Knife Re-
placement).