Bq 3.2 Burr Marks; Bq 3.3 Jagged Bottom Cover; Bq 3.4 Burr Marks/Jagged Cover - Challenge CMT-130TC Service Manual

BQ 3.2 Burr Marks

Description
Burr marks are found on books trimmed with a
knife that has a burred cutting edge. 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, or books with sta-
ples.
Solutions

Replace the knife (REP 4.2 Knife Re-
placement).
CMT-130TC Book Trimmer

BQ 3.3 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 cut stick may be worn.

The knife may be dull.
Solutions

Rotate or replace the cut stick (REP 4.1
Cut Stick Replacement).

Replace the knife (REP 4.2 Knife Re-
placement).
MAY 2019
3-3

BQ 3.4 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 jagged
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).
3. Book Quality