Bio-Rad Helios® Gene Gun System - Manual (Page 46)

10.4 Replacing the razor blade on the Tubing Cutter and disas-
sembly of the unit
The cutting edge of the Tubing Cutter is a standard, single edge razor blade. Because cut-
ting is done only on one end of the blade at once, it can be rotated after the first end becomes dull.
The first sign of a dull blade will be incomplete cutting of two adjacent cartridges. Front refers
to the side of the Tubing Cutter with the tubing channels. Right, left, and back refer to the sides
of the Tubing Cutter when the user faces the front of the unit (see Figure 23).
1. Loosen the red locking knob on the back of the Tubing Cutter by turning it approximately one
full turn until the lock block on the rear of the cutting arm is free to move.
2. Move the lock block to the right to free the razor blade retaining screw on the right side.
3. Lift up on the right side of the razor blade until it can be lifted free of the Tubing Cutter.
4. Insert a new blade (or rotate the old blade 180˚) by inserting the notch on the left side of the
blade into the retaining screw on the left side of the cutting arm.
5. Hold the razor blade so that the notch on the blade is next to retaining screw on the right side
of the cutting arm. Using the red locking knob, move the retaining screw into the notch in the
razor blade and turn the locking knob clockwise to lock the razor blade in place.
Fig. 23. The Tubing Cutter.
The Tubing Cutter may be disassembled for cleaning. For safety, remove the razor blade
prior to disassembly.
1. Place the Tubing Cutter in front of you on a solid surface so that you are facing the front of
the unit.
2. Hold the base between the thumb and index finger of your right hand. At the same time,
push the left side of the Tubing Cutter arm to the right with the index finger of your left hand.
This will disengage the arm from the pivot pin on the left side of the base and from the retain-
ing pin on the right side of the base — the tension on the spring will push the arm up.
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