Jumping into CNC milling and figuring out feeds and speeds definitely takes a bit of trial and error, especially with different materials like mild steel, which you’re working with. For mild steel using a 1/4" HSS endmill, you might want to start with lower RPMs, around 3000, and a feed rate of about 15 ipm. See how your machine handles that and tweak it from there.

Remember, it’s all about making small changes and seeing how your part turns out. Don’t stress too much because everyone goes through some adjustments to find what works best.