Milling: creating a smooth end finish in a slot

[Rob Meades]

Thanks for the swift response and offer of help, here's some more detail. First, the machine (High-Z S-400/T):



Then, the material overall:



Then the cut; left is early on when some clear-outs are being cut, middle is at the start of the slot-cut (where the right-hand side of the picture is the earliest, the left-hand side is several minutes later) and finally right is the slot-cut just before the bit snapped:



For good measure, here's a video of the slot-cut phase, taken shortly before the right-hand side of the middle picture was cut.