Despite our best preparation, it is possible that during shipping, the counterweight cable could break. This may result in inconsistent toolchanges and Z-axis moves.

This job should take 45 minutes to 1 hour from start to finish.  You only need the allen wrenches that came with your machine, but it is helpful if you have a right-angle hex driver. 

IMPORTANT! Before starting this work, move the z axis to the center of its travel, then power off and unplug the machine. NEVER REACH INTO THE AXIS MECHANISM WITH THE MACHINE POWERED ON. This machine generates plenty of force to crush your hands. The turret should also be homed (with the probe pointing down).

Background: The H-Series counterweight serves 2 functions.  It counterbalances the weight of the arm/turret assembly and it provides a torsional preload to the turret.  It is critical to the function of the machine, so this maintenance work must be done with care.  The routing of the cable is shown in the diagram below:

1. Disassemble cover components

Remove the upper and lower Z bellows cover, the turret gear cover, and slide the upper build enclosure panels to the side.

2. Detach cable and uninstall pulley bracket

At this point, you may detach the cable from the turret. Uninstall the upper pulley bracket by loosening the set screws on the shafts and removing 2x M5 screws (use right-angle adapter if available).

3. Remove counterweight and replace cable

Remove the counterweight by pulling on the cable until it clears the shafts. If the cable is broken below this point, you will need an M6 threaded rod (we will provide one with the replacement cable if necessary). 

Remove the hex bolt/cable assembly from the counterweight, and replace with the new assembly.

4. Rethread and attach cable

• Gently lower the counterweight over the shafts using the new cable or threaded rod.
• Shim the counterweight off the bottom surface by 1-2mm. 
• Reinstall the upper pulley bracket. Torque M5 screws to 22in-lb. Hand-tighten the shaft set screws
• Thread the cable over the 2 upper pulleys, behind the pulley at the back of the arm (cable should be in FRONT of the Z-limit switch blade) over the pulley at the front of the arm, and over the top of the turret.
• Keeping the cable taught, and ensuring it remains over all pulleys, loop the cable over the anchoring screw on the turret and tighten to 3in-lbs. The cable should be clamped under approximately 270 degrees of the screw head, and shall not overlap itself
• Trim off excess cable.
• Remove shim.

5. Reinstall shrouding

• Slide upper build enclosure panels back in place and hand-tighten screws
• Reinstall Z bellows 
• Carefully install gear cover with 2x screws from the +X side of the turret, and 2x screws from the -X side