It is also possible to produce cone-shaped CFEs of various sizes with another machine called "microforge" without using the micro-grinding machine (Figure 1[C.sub.II]).
Borosilicate glass with filament (Sutter) was pulled with a PC-10 pipette puller (Narishige) and polished with MF-830 microforge (Narishige) to resistance of 3-5 MOhm.
The patch pipettes were made from Kimax capillary tubes (Vineland, NJ) using a vertical two-step electrode puller (Narishige PB-7, Japan) and the tips were fire-polished with a microforge (Narishige MF-83, Japan).