Drill Doctor DD500X Twist Drill Bit Sharpener - 3/32" to 1/2" - Electric Sharpener - High Speed & Portable - For Steel, Masonry, Carbide & Tin-Coated Drill Bits - Adjustable 118° or 135° Angle

I have used several drill bit sharpeners over the years and most were difficult to use or just plain worthless. The industrial grade sharpeners we used in the machine shop I used to work in did the job, but were not only expensive, but had a steep learning curve. At just a tad under 110 dollars, the Drill Doctor is one of the most expensive units out there, but unlike the competition, it not only works well, its also made in the USA. After receiving the unit, I spend a couple of evenings sharpening most of the drill bits I owned. I found the larger, over 1/4 inch bits to be extremely easy to set up in the chuck and sharpen. I did have some trouble with the smaller bits, though. It says that 3/16 is the smallest, but I was able to sharpen a long 1/8 bit easily. Different grades of sharpening stone and a larger chuck is also available if needed. For the moment, this unit is more than adequate for my needs and for most other garage mechanics and handymen out there.

When I read some of the reviews and videos online, I wasn't sure if this was a good product or not. One video showed a negative angle on the cutting edge that would leave the bit useless. After sharpening an entire set of 29 drill bits, I am glad that I made the purchase. and I am pretty sure that the user who couldn't get his bits sharp didn't have the bit rotated properly in the bit chuck. After sharpening the bits with the Drill Doctor I also realized that they are now sharper than they were new. I don't have many bits larger than 1/2" so I didn't step up to the DD750, but after using this sharpener I wonder if I shouldn't have gotten the larger version so that I could keep those bits sharp as well. I have an entire drawer full of discarded dull drill bits that I will soon sharpen. Great tool and I would recommend.

I bought this machine a few months ago. I've used it to sharpen quite a few bits, 50+ ranging from HSS to masonry. I will emphasize that you MUST read the instructions thoroughly, and watch the DVD as well. It is important to know how the tool works, and why you will ruin bits if you don't follow the instructions.To sharpen standard 118* bits couldn't be easier. This machine does an excellent job of it, and since I use most of my drill bits to drill in wood, this is the perfect angle for me. Split points can be ground on 118* bits, and I have done this with success. To sharpen masonry bits is also very easy, and the machine does an excellent job in this regard as well.Where it gets tricky, for me anyway, is in sharpening 135* split point bits. These days nearly all bits sold are this type and it's nice to be able to recreate the same angle and split point. While I have sharpened bits of this angle with success, I haven't been able to get perfect results all the time. Proper alignment is critical. Trying to adjust the relief angle seems to make proper sharpening more difficult and I would not recommend it to someone who just got his hands on this machine. The relief angle is adjusted by putting the chuck to either side of the 118* alignment slot (the + and - increase and decrease the angle). This is to allow a more aggressive or less aggressive cut. Fiddling with this adjustment seems to throw off the split point when it is being ground as well, taking off way too much material. If too much material is removed during the split point procedure, subsequent sharpening of the bit will not yield the same angle since the alignment fingers will not hold the bit from is flutes, but from the newly ground area behind the split point. It is hard to visualize this, the mistake must be made to understand it fully.Changing the diamond wheel is straight forward and easily done. The machine has a somewhat loud squeal when running, but it isn't too bad. I have sharpened broken bits with success, so that feature definitely works. Also, unless a bit really damaged during a botched sharpening attempt, it can most probably be sharpened to at least a 118* point again, though it will take a while and several alignment and sharpening procedures. I recommend the 100 grit wheel for when this must be done as it will take less time, and then a follow up can be done with the standard 180 grit wheel. The 750X has more features than just being able to accommodate larger bits, so in my opinion it is definitely worth it. I wish I had gotten that model instead, and I believe sharpening 135* and split points would be easier and faster. This is a quality product though, that I must say.**EDIT 7/26/08**After using my DD extensively during a project to sharpen a masonry bit, I noticed something that I hadn't observed earlier. When sharpening the bits according to the instructions, the machine does not put opposing angles on the tip of the bit. That is, it grinds both sides of the tip to an arrow point, and this is NOT conducive to easy drilling. In fact, I realize that I put unnecessary load on my drill using the "sharpened" bit. Perhaps experimenting with bit alignment might help, but that can just as easily ruin a bit you're trying to breath more life into.**EDIT 8/3/10**I am adding an edit to this review, mostly to address other reviews and comments about people needing to read and follow the instructions. On *MY* machine, only the 118* angle is indicated on the alignment port. There is NO mention of 135* angle, and this is why I had problems with aligning and sharpening 135* split point bits. After much experimentation and frustration, I finally got the 135* angle by inserting the chuck into the "-" slot, then putting the sharpening port at 135*. I don't know if my machine had a quality control issue, or if all the DD500X units are like this. To split the point on 118* or 135* bits, you need to align the bit at 118* regardless of the angle you sharpened the bit to. In splitting the point, it must be done carefully to avoid under-splitting because if that happens, the bit will NOT cut. For 135* bits, if the point isn't split, it really won't cut unless you're drilling into a very soft material like plastic or wood.A long review for certain, and a good machine, but not without faults. After owning my machine for a couple of years and using it extensively I feel my four star review of "very good but not excellent" is fully justified.

As a retired Tool and Die maker I missed access to the great machinery I used to use to make things, so I got a small shop going in my basement with a lathe, mini mill, drill press, etc. At work we had a beautiful Black Diamond drill bit sharpener the size of a kitchen stove which really spoiled me. As my drill bits got dull with use I really missed the sharpener and decided to try the much vaunted Drill Doctor. I gave you the preliminary stuff here so you would know my background on this. I expected poor results from this small machine. I was surprised. Very easy to learn but its method of operation is somewhat similar to the fantastic tool I used for decades at work so my learning curve was probably faster than someone who is not a machinist or toolmaker. Still, the instructions were clear and frankly if you are using your drill bits enough for them to require sharpening I assume you have your wits about you. Admittedly the bits came out looking a bit sorry...not like the professional machine at all. There are and will be scratches and gouges on the ground surface (by easing up on the pressure you apply for the last few revolutions of the bit you can minimize this but it will still be present). But I am a results oriented guy. The purpose of a drill bit for me is to drill a reasonably accurate non wandering hole in a piece of metal. The somewhat sorry looking bits worked perfectly! I was impressed. IT DID WHAT IT WAS SUPPOSED TO. I have read reviews here where people complain of the finish of the sharpened surface, they are correct BUT was the formerly dull and useless bit now sharp and useful? Yes it was. Don't lose sight of the big picture....no one wants to be in the middle of a job where you need to tap or ream a hole and you find your bit is dull or the tip broken off and the last thing you want to do is go to the store, if its open, to buy another bit only to find they are out of stock on that size and besides that the bits they have are cheap imported junk. I have gone through my entire fractional, letter, and number bits and sharpened the dull ones with this Drill Doctor without any regrets. It will not do the tiny sizes since they wont fit in the holder, but those tiny sizes I keep several on hand since they dull fast and break faster! Has held up well so far, If this tool is ever lost or destroyed I certainly would buy another, probably the same model.