Thread: Trimmer speed problem

Google "Difference Between Router and Trim Router?" a mini or a flat bed truck?

Why the rpm difference? Short answer is cutter "cutting speed" the rate at which the cutting edge is travelling in meters per second (or feet per minute). A small circumference cutter requires a higher rpm to achieve the desired cutting edge speed. Trim router bits are rarely larger than 19mm dia where as edge profile router bits etc are often well above 30mm dia.

Basically, whilst performing similar roles, the Trim Router is designed for a specific task - trim routing. They are typically compact easily maneuvered machines that can access tighter areas. They usually have power at or below 750W (1hp) and have a much higher and typically fixed spindle speed because they are designed to run small circumference trim bits at their optimal high rpm.

Convention routers are larger more powerful, robust, general purpose machines (1 to 3 hp or more), with components designed to handle the demanding loads of larger circumference router bits. They may have fixed spindle speed, though they are typically variable speed to run a range of small to large diameter router bits at optimal cutting speeds (m/s or f/m).

The manufacturers of router cutters recommended rpm for each design of bit is the theoretical maximum safe operating speed (like safe working loads) within engineering standards safety margins.and should not be exceeded. Doing so may destroy the bit - not a nice scenario!

Cutting technology and router bit design seeks to optimize cutter rpm, thus linear cutting speed of the cutting edge/s, machine feed rate, cutter diameter, cutter profile, cutter gullet and recommended cutter depth per pass to control chip size and chip ejection for optimal performance and "off the cutter" surface finish.

Getting Started With Speeds & Feeds explains the principles.

Good explanation
Thank you