Mechanical System; Knife Return Springs - Challenge SCM Instructions And Parts Manual

8.1 Mechanical System

8.1.1 Knife Return Springs

It may be necessary to adjust the knife return spring(s) at some time. More compression increases
the return force while less compression reduces the return force. The length of the spring should be
adjusted between 13-3/4 and 14 inches. Do not compress the spring(s) more than necessary. Over-
compression will cause undo wear to the spring(s). The following procedure describes how to adjust
the spring compression.
1. Switch off the machine and disconnect power (SCM models only).
2. Open the top cover.
3. Loosen the top jam nut on the end of the knife return rod.
4. Turn the lower jam nut clockwise to increase the compression on the spring(s).
5. Turn the lower jam nut counter-clockwise to decrease the compression on the spring(s).
6. Retighten the top jam nut onto the lower jam nut to lock it in place.
7. Close the top cover.
8. Reconnect power to the machine (SCM models only).
Disconnect main power.
See Section 2.2 Power Lockout Procedure.
Figure 15 – Spring Compression Adjustment
8.0 Appendix A - Maintenance Guide
19