Yes Jeff, metal film resistors can be spiral cut during trimming.
But the inductance increase is usually very? small and in series
with a much higher resistance. The inductance of a wire ended
quarter Watt resistor is around 0.02uH? max so XL is around 0.1
ohms at 1MHz. For many metal film resistors the inductance is
smaller than 0.02uH - depends on the manufacturer and how they
trim. Some metal film wire ended resistors are not spiral cut.
Surface mount resistors can be trimmed with a short line, they
have very low inductance hardly altered by trimming.
The spiral trimming process has been around since the 1930's,
originally with carbon film resistors and abrasive loaded air
jets. Makers could use a standard rough coating process then
spiral cut the coating to make resistors of 10-20 times higher
value and charge more for higher precision. Generally don't worry
about the inductance of metal film wire ended resistors unless you
are using 100 ohms or less at frequencies above 10MHz.
Regards, Alan G8LCO
