The two spots are earlier successful spot welds that hold everything in place. All drilling is done at a low speed, well below the 100 ft/min recommendation for drilling steel. This will drill the unequal heights with ease, and the point is captured in the divot made by the spotting drill. This is also a spotting drill, and is short and relatively stiff. The second and third pictures are for the main drill, which is about 5/16' in diameter. If you don't clamp this setup well, you will find out as soon as the drill hits the part.

The trick is to bury the point before the drill does an appreciable amount of side loading. The drill is short and relatively stiff, and can withstand some side loading. Also note that the transition has been relieved near the drill point with a file. That is due to a belated relief feature machined on the opposite side where the shaft is pressed in up to a collar. Note that the shaft is proud of the surface of the puck.

In the first picture, a small spotting drill is posed to take a peck in preparation for drilling a hole for a spot weld. I am attaching three photos of my latest attempt at milling on the drill press. The question is how much can one get away with before the dreaded taper disassembly and potential resulting hazard. The reason I thought of this is that drill bits wander (as the mind does), and in a sense, there are side loads associated with the wandering (else why would the bit wander). Typically, this question is asked by a beginner, and the group answer is usually 'NO', because the drill press is not designed to handle side loads. I don't have a vertical mill, and sometimes the thought crosses my mind about milling on the drill press. Recently, I have been revisiting this topic, and with the recent post on 'safety third', I thought I would share some observations.

Mills hole in one slot machine