I need a good endmill for routing 1/4" or less Aluminum plate using an X-CARVE CNC router using a Dewalt 611 spindal. The Spindal is 400W, and turns at 16000-27000RPM. The spindal can accept 1/4" and 1/8" shanks. All cutting will be 2D and I'm looking for the shortest total routing time possible. I was looking at your tool #51408, but was not sure if a 1/4" cut diameter would be better. I'm also not sure how much longer than 1/4" the cutting length should be. Any help you can give would be great.
Based on the available RPMs you have of 16,000 to 27,000 this which translates into a Surface Feet Minute range of 1,048 to 1,768. You are approaching the upper range limit of this uncoated tool.
We a ZrN coated tool, our part number # 51452 which was designed for aluminum. This tool measures as ¼” D X ¼” B X ¼” d X 2” OAL. The ZrN dramatically increase the safe RPM range. I would go with this tool.