Drill Doctor DD750X Drill Bit Sharpener Review
It sharpens blunt bits back to cutting, including split points, up to 3/4 in. The learning curve is the part nobody warns you about.
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A drill bit does not usually break; it goes blunt, and a blunt bit gets replaced because sharpening one by hand on a bench grinder is a skill most people never acquire. That is the market the Drill Doctor exists in: a jig that constrains the bit and the wheel into the right relationship so an unskilled grind comes out symmetrical.
The 750X is the top of the line. Capacity runs from 3/32 in to 3/4 in — the 3/4 in chuck is included rather than optional, which is the main hardware difference from the 500X below it. Point angles are adjustable continuously from 115 to 140 degrees. It grinds high-speed steel, black oxide, cobalt, carbide, masonry and TiN-coated bits, using a 180-grit diamond wheel that comes installed.
Split points are the reason to buy this one
A standard drill point has a chisel edge across its centre that does no cutting — it scrapes and pushes. On a hard or curved surface that chisel edge is what makes the bit skate before it bites. A split point grinds that chisel edge away into two small cutting edges, so the bit starts where you put it and needs much less feed pressure.
The 750X will both create a split point on a bit that never had one and restore it on a bit that has been ground away. There is a push-to-stop feature to keep you from over-splitting. This is the single feature that justifies stepping up from the cheaper models, and it is more useful than it sounds — it effectively upgrades a drawer of ordinary bits.
The part that frustrates people
Sharpening happens in two stages: you set the bit in the alignment port, which establishes how far it protrudes and how it is rotated relative to the flutes, then you transfer it to the chuck and grind. If the alignment is wrong, the grind is still symmetrical and still pretty, and the bit still will not cut.
The manual explains it and the procedure is not hard, but it is not intuitive either, and nearly every owner ruins a couple of bits working it out. Practise on bits you have already written off. Once the setup clicks it takes under a minute per bit.
Running costs and honest limits
The diamond wheel wears. A replacement costs enough to notice, and a coarser 100-grit wheel is available for badly damaged bits. Budget for at least one wheel over the machine’s life.
The build is light-feeling plastic over a permanent-magnet motor, backed by a three-year warranty. It is not a machine-shop tool, it is loud, and it throws abrasive dust — run it away from anything with sliding ways.
The economics are simple. If you drill mostly softwood and buy a set of bits every few years, this will never pay for itself. If you drill steel, or own a hundred bits, it does so quickly.
What works
- It creates and restores split points, which is the feature that separates the 750X from the cheaper Drill Doctors — a split point is what stops a bit walking on a curved or hard surface
- Point angle is adjustable anywhere from 115 to 140 degrees, so you can grind 118 for general steel and 135 for stainless rather than accepting one factory angle
- Takes bits from 3/32 in up to 3/4 in with the included 3/4 in chuck, and handles cobalt, carbide, masonry and TiN-coated bits as well as plain HSS
What doesn't
- The alignment port setup is fiddly and unforgiving: get the bit seated wrong and you will grind a perfectly symmetrical, perfectly useless point, and most people ruin two or three bits learning
- The 180-grit diamond wheel is a consumable and replacements are a meaningful fraction of the machine price
- It is noisy, throws grinding dust, and the plastic housing feels light next to the job it is doing