Actually and at least up to a 1-3/8" forstner bit 700 is plenty slow. With a single bit I have drilled in excess of 1000 holes at that speed with no resharpening and no burning of the wood or discoloration of the bit.
If you are only doing wood/aluminum/plastic then the multispeeds should be fine. If you want to do ferrous metals, then it's very difficult to beat a variable (electronic) speed. I would buy a standard multispeed and toss the AC motor. Get a surplus DC motor (GOOD one) and a solid state controller. You can use a Variac and a bridge rectifier to save some, if you want. Now you can drill a 1" hole in tool steel or aluminum or and wood product. With the DC motor, you want to tap something, no problem. Reversing is simple. I know, not for everyone but I would hate do do without it. The option, of course, is to buy a 3phase DP that have limited resale value (used/auction) and add a VFD. Will do the same things. Respectfully, Ron Moore
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