I’ve been asked to make a pickguard for a guitar out of anodized aluminum. The sheet is .040" thick. What feeds and speeds are recommended. I have a 1/8" 3 flute aluminum series end mill from Bits & Bits.
I’ve never used that bit but looking at it online I’d suggest looking at a single flute bit with a lower helical angle for a .040" thick sheet, your work holding will be a concern with such an aggressive upward pull of the bit, it will want to lift your sheet from the waste board. Typically for a guitar pickguard you’ll also need a chamfering bit for the edges of it and to create counter sink bores for the screw heads as well
If you do give it a go with the bit you already have they specify a chip load of .001" which would be a good starting point - your CAM software can likely calculate it for you based on your feed rate and RPM.