Have an inventory of many drill bits - mostly standard sizes in a variety of diameters, some of them with broken ends, and a few rusted spade bits. After talking with a "sharpening guy" and his prices for each bit (@ about $2.00 each), looked on line & found "Drill Doctor" drill sharpening device at $130. Have you tried this device and is it REALLY worth the time & $ to get one? How do you economically sharpen both standard AND spade bits? As always your input is appreciated.
I purchased a Drill Doctor DD750X in 2013 for sharpening my expensive drill bits (it was on sale for $120). It has already paid for itself. I have some 18" long bits that I use for some deep holes. They are $30 and up for each one of the bits. It only took resharpening four (4) of these bits to pay for the Drill Doctor. I will occasionally hit a screw or other object that ruins the bit. Now with the Drill Doctor, the bit just gets a little shorter and a whole lot sharper.
I don't waste my time trying to sharpen inexpensive bits, I usually just go to the store and buy more.
I have never tried to sharpen spade bits, since I don't use them very often. The holes they produce are too sloppy for my work.
Auger bits, I sometimes sharpen by hand, but usually just replace them.
Forstner bits, I sharpen by hand or just replace them.
HSS bits, I just purchase new ones.
Expensive bits I use the Drill Doctor.
Your decision really comes down to these factors:
-> your drill bit cost
-> your sharpening skills (mine suck!)
-> how much your time costs, going to the store to purchase new bits