I purchased the DD750X for home use to sharpen my dulling cobalt and TiN-coated drill bits as it seemed that the price of the sharpener was less than replacing all of them. I mainly drill into hard wood and soft to medium metals. I agree with the other reviewer that drilling into metal requires slow speeds and cutting oil, but even the cobalt bits dull fairly quickly when going into steel. The sharpener does do a good job of bringing a dull bit back to life, but is not a replacement for professional resharpening or a new bit. The kit comes with the sharpener with sharpening wheel, a chuck for up to ¾” bits, a DVD instructional video, a paper manual, and a plastic carrying case. The DVD is a good primer, but provides little actual direction. The paper manual has much more detail about how to sharpen various types of bits. The DD750X, unlike the DD500X, can be adjusted for any tip angle between 118 and 135 steplessly as well as how much is taken off when sharpening. The latter adjustment is very useful in just taking off a hair to add an edge without losing too much material. The 750 also accepts up to a ¾” bit while the 500 only goes to ½”. To sharpen, the bit is placed in the chuck and aligned using the mechanism at the top of the tool. The amount to take off is adjusted here as well. To sharpen, the chuck is placed in the sharpening cam and turned. Each full turn sharpens each side of the bit. The process is fairly foolproof as the cam and guide maneuver the bit at the correct angle on the sharpening stone. The grinding noise—or lack of it with successive passes—is indicative of whether it’s fully sharpened. Masonry bit spade tips are sharpened with the same chuck but without turning. The sharpened tip looks very even with very few burr marks. It appears even and razor sharp and cuts as good as new. The tip can be split by inserting it in the hole on the side of a machine. Split-point tips are better for starting new holes and removing material quickly. I agree with the other reviewer that this is where the sharpener is lacking. It takes quite a bit of practice to split the point correctly and is never as good as from a professional sharpener. A note of caution: use the safety cover on the top hole when splitting the point as sparks fly out here toward your eye. Overall, I am very satisfied with the machine as it has already saved me hundreds of dollars in reviving my old bits instead of buying new ones. I purchased the 750 instead of the 500 because of the ability to adjust how much is taken off with each pass. The machine appears solidly made with a metal frame, although the chuck is plastic. The guides are not wobbly so the user does not have to be skilled to give a symmetric tip. The diamond wheel seems to remain usable after many uses. I would not recommend using the sharpener to add a split point.

Epinions.com Feb 6th 2007

purchased the DD750 Pro Kit for my shop after we started drilling a lot of large holes in metal. With the average 1/2" bit costing a minimum of $10, it didn't take long to convince myself that this would be a cost saving tool. Contrary to what a previous reviewer stated about the bits not staying sharp as long, he's partly correct but the difference isn't enough to justify purchasing new bits. If you overheat a drill bit when cutting metal by not using cutting fluid/cutting oil, or spinning the bit too fast, then yes the bits won't stay sharp as long because you've taken some of the hardness out of them. You can use metal bits to cut through steel without any coolant but they'll dull faster, and won't take a very good edge from then on no matter if they're professionally sharpened, or sharpened on the DD750. But if you cut with proper (SLOW) speed, good pressure and most importantly USE CUTTING OIL on metal, your bits will stay sharper much longer and you won't notice much of a difference in the time the bit stays sharp when you do have to touch them up with the DD750. What you will notice most is the difference between a factory split-point bit and the Drill Doctor split-point. This is the one area where I think that the machine needs improvement. With lots and lots of practice I could get a descent split point tip, but no where close to a factory edge! If I need a good fast cutting split-point bit for cast or hardened steel, I'll buy one and take good care of it. After it's dull I'll use the DD750 to put a standard tip on it and use it for more common tasks. A split point bit cuts a lot faster than a standard point, but in standard cold rolled steel I find that economics win out. The DD750 saves me money! I'm kind of a perfectionist when it comes to tools so I really didn't want to give it a top rating. But, my shop manager reminded me of all the time I had saved by not having to run to the hardware store for new bits. And how I could sharpen a bit in less than 5 minutes. And that the tool was not really that expensive (I purchased the DD750 Pro Kit for $129 delivered). So all in all I had to agree. The only other tool that's even close to the DD750's abilities is around $1000. You can also buy a smaller (and less expensive) Drill Doctor if you never use large bits but I'm not sure if they do as well as this one!

 Epinions.com May 19 2005