Originally Posted by
irving2008
Dremel simply doesnt have the grunt needed. the rotozip will work and has been used elsewhere. For example here in the UK the Bosch RZ3 is a 600W device (about 300W output) so has some grunt, but is limited to a 3.2mm collet so can only use small cutters. The bigger RZ5 can take 6.4mm (1/4"). Both have the difficulty of mounting as they don't have a nice shape but I believe they have a accessory collar.
At the end of the day the thickness of material being worked isnt directly relevant, its the depth of cut and the feed speeds relative to the rpm of the cutter and its torque. a 1/4" 2 flute cutter at 30ipm on a 0.02" DOC on aluminium needs about 150W of spindle power, far too high for a Dremel but the RZ5 will just about handle it OK. Obviously deep cuts in thick material needs several passes and accuracy is limited as the length of the cutter compared to its diameter allows a degree of flex.
I use a Dewalt 500W diegrinder (see pic) which handles 6mm shank cutters and will do ally quite well and has the advantage of a nice square shape above a standard 43mm mounting collar.
If you want to use a bigger cutter, up to 1/2", to get faster cuts or more accurate cuts at depth in thick material then you'll need lots of torque and 1200W input so a full-size router is the way to go.