Having tried a Dremel DP, I'm not real impressed with the accuracy. I've tried both the current version as well as an older, better made version. In both cases, they could not be depended on to hit a specific point. That's one reason for the HF minimill. The other was speed; I do a lot of work with plastics for electrical insulation. Drilling into the side of (almost 1/4) 6mm(?) PlexiGlas, the drill would heat up the plastic, melting it to the point that the 2-56 tap would slip in and out of a 1/16 hole. I solved the problem(s) by drilling very slow. The minimill has good repeatability, coming down the same place most every time. I can now tap a 1/16 hole and trust the finished size.
As a rule, small drills need to run fast, the smaller the faster. Working with acrylics, slower speed is necessary when the hole must be accurate. For drilling metal, a good center punch helps immensly to keep the drill running true. I use a 'prick' punch more often than a 'center' punch.
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