Impressions on Drill Doctor 750X

devils4ever

devils4ever

H-M Supporter - Gold Member
H-M Supporter Gold Member
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May 13, 2019
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So, I've had my Drill Doctor 750X for a little bit now and I've had enough time to evaluate it.

Overall, I'm very pleased with this tool. I've sharpened a bunch of bits and they all cut much better than before. Do they cut as good a factory grind? No, but they are close. Be warned that there is a learning curve on using this as with most tools. There is a bit of fiddling that needs to be worked out.

Any owners out there or potential owners out there should watch this video. It is crucial to getting the angles correct. I blindly used the 118* alignment port initially for my bits and found that the geometry is off. You need to try the different notches on the alignment port to get the chisel angle correct. The chisel angle should be set as follows: align the cutting flute horizontally and the chisel angle should be a 1 o'clock. This is explained in the video. The angle varies based on drill bit diameter and how fast the spiral on the flute is. Makes sense.

The video is a little long but explains this. I start with the "official" notch on the alignment port and do a quick grind to see what the chisel angle is and adjust accordingly. Typically, I need to go 1 or 2 notches to the right.

Now, onto 135* split point bits. I've not had good success on these. The 135* grind is fine and works well. It's the split point operation that is troublesome. I tried doing this on a 1/4" screw length bit. The relief cut was way to deep and took off way too much metal. See photos. I suppose I need to adjust the geometry as well. If anyone has seen this and know of a solution, please post.

IMG_5733.jpg

IMG_5735.jpg
 
I wore out 2 of the DD750Xs, was working on my third, when I broke down and bought a MR -26A and a MR-13B, drill bit sharpeners. While I had great success with the DD750X, the new sharpeners are about 1000% better, but it also came at a cost of about $800 when I got done. The is a learning curve with the DD750X, but when mastered it works very well.
 
Last edited:
Buffalo21 said:
I wore out 2 of the DD750Xs, was working on my third, when I broke dow and bought a MR -26A and a MR-13B, drill bit sharpeners. While I had great success with the DD750X, the new sharpeners are about 1000% better, but it also came at a cost of about $800 when I got done. The is a learning curve with the DD750X, but when mastered it works very well.
Click to expand...

Do you have more info on these?
 
the MR-26A


the prices fluctuate wildly, depending on supplier, but the all offer the same basic machine, just different names and colors
 
Thank you for giving us your review or your first impression of the Drill Doctor, I'm sure as Jack mentioned there are many other drill bit sharpeners some better some worse but the DD with all it's shortcomings still lives on and stay popular especially amongst many hobbyist.
I personally prefer to buy a new set of bits and splurge on the quality only because I know it will last me a life time but if I ever change direction in my hobby and end up drilling holes a few times per day, I will definitely look at the DD first because it still seems to be reliably functional and very affordable.
 
As a hobby user, I decided to try one based on the reviews from members here. I think it is a good way to go for hobby users. I can't speak to pro guys needing to keep more bits sharp. It's likely a lot slower than the more expensive units.

I decided to test on a worst case, broken off bit. I just used a bench grinder to get a somewhat close angle on the end and remove a long area along one flute. Just to speed up the process a bit. The DD did a great job for the amount of effort for a first time sharpening a drill. The result cuts metals nicely. Perhaps not as good as the factory grind on nicer bits, but better than the HF bits I have for my wife/kids to break. I just did a 118 degree grind as the machine was set up for it when I got it.

As usual, the included instructions are kind of crap. But I watched a couple of videos about it before it got here and had the basics figured out. It's not perfect, but it's a lot better than dull or broken bits.
 
Mine has paid for itself many times over.

Drills that would otherwise have been thrown away and replaced, are now used up like a pencil. Now they don't get replaced until they're too short to sharpen anymore.

It doesn't make them as good as new, but they certainly work. The split points suck, but I suspect I could fix that by turning the wheel arbors shoulder back a couple hundredths to move the wheel a little closer to the motor. I'll experiment with that one day.
 
I bought my initial drill bit set about 35 years ago. Gasp! It was a HSS 118* USA made set and served my well for all those years. I was mainly doing woodworking and only needed to replace bits that I broke.

Now, that I'm drilling steel and other metals, I need to replace them much more often. I've been buying 135* split point bits to replace them as they dull. I've been buying Chicago-Latrobe bits and they are excellent, but are $$$ especially in the larger sizes. So, I decided to break down and get the sharpener. I will probably still buy bits, but not as often.

I could have bought a more expensive one, but I'm hoping this will meet my needs. I'm not a production shop, it's just a hobby.

I need to drill 45 0.201" holes in 1/2" steel soon for a tooling plate. I'm sure I'll be re-sharpening this bit afterwards rather than having to buy a new bit saving money.

I'm thinking if I keep them sharp rather than waiting until they're really dull, it will be much easier.
 
So, I need to sharpen a 1/2" 135* split point bit. Since I had poor success with the split point operation, is it better to convert this to 118* or can I still make it 135* without the split point?
 
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