Replacing and Adjusting Knives on Fischbein Model 100 & 101 Sewing Heads

Maintaining sharp, properly adjusted cutting blades is essential for the performance of Fischbein Model 100 and 101 industrial sewing heads. Depending on your specific model, the cutting mechanism will either be a standard knife assembly (Model 100) or a specialized tape/thread clipper (Model 101).

This technical guide outlines the procedures for replacement, adjustment, and preventative maintenance to ensure clean cuts and prevent machine downtime.

1. Safety and Preparation

Before performing any maintenance on the cutting assembly, strictly adhere to the following safety protocols:

  • Power Down: Disconnect the electrical power supply and lock out any air source if connected.
  • Personal Protective Equipment (PPE): Wear puncture-resistant gloves when handling blades.
  • Tool Requirements: Ensure you have the appropriate hex keys and wrenches specified in the Fischbein service kit.

2. Replacement Procedure: Model 101 (Clipper Blades)

The Model 101 utilizes a clipper-style blade system designed to cut both the thread and the crepe tape.

Removal

  1. Access the clipper assembly located behind the presser foot.
  2. Loosen the mounting screws securing the used worn blades.
  3. Carefully remove the old knive blades, noting their orientation to ensure the new set is installed correctly.

Installation

  1. Position the new knive blades into the assembly.
  2. Tighten the mounting fasteners. Note: Over-tightening can cause binding, while under-tightening leads to misalignment.
  3. Manual Lubrication: Immediately following installation, apply standard lubricating oil directly to the blades to prevent heat buildup and friction during the first cycles of operation.

3. Adjustment: Model 100 (Rotary Air Knife)

The Model 100 often features a rotary air knife. Proper synchronization between the sewing cycle and the knife rotation is critical.

  • Mounting: Refer to the mounting bracket assembly to ensure the knife is positioned at the correct distance from the needle path.
  • Timing: The knife must trigger only after the bag has cleared the needle area to prevent premature cutting of the thread chain.
  • Clearance: Check the clearance between the stationary and moving blades; there should be minimal a gap to ensure a “scissor” action rather than a tearing motion.

4. Preventative Maintenance & Troubleshooting

Daily Maintenance

  • Debris Removal: Use compressed air (max 30 psi) or a vacuum to remove lint, dust, and thread scraps from the knife housing. Accumulation in this area is the primary cause of blade dulling and mechanical jams.
  • Fastener Check: Vibration from industrial sewing can loosen knife mounting bolts. Inspect and torque all fasteners daily to maintain critical settings.

Identifying Wear

Replace blades immediately if you observe the following:

  • Frayed Thread: The thread chain is not cut cleanly, leaving long tails or “pulled” threads.
  • Tape Tearing: The crepe tape shows jagged edges rather than a straight, crisp cut.
  • Increased Noise: A “clicking” sound near the clipper assembly often indicates blades are misaligned or striking the throat plate.