Drill Doctor 750 review

[Forrest Addy]

So to amend my review and removing errors:

Taking a break from more onerous tasks, I got out a Christmas present for the first time to see if would perform better than my skepticism predicted. Yup. My rotten grandlings got tired of listening to me bellyache about not being able to see well enough to sharpen drills free hand so they got me a Drill Doctor 750 for Christmas.

First impressions. Neat compact kit in a blow molded case with all accessories, two chuck/cam arrangements, a little wrench for changing the grinding wheel, and finally a video tape in case my famous instant mastery of all things mechanical suddenly lapsed. Everything made sense and went together in a logical sequence. The instructions were crystal clear with plenty of illustrations to guide each step. There are numbers on the case of the Drill Doctor to follow so you don't mix up any steps.

This gadget performs as advertised. It'sa claimed capacit is twist drills from 3/32" to 7/3". Follow the steps and you can sharpen a drill as well as I could in my prime (which is pretty damn good if I do say so). You have a choice of conventional grind or split point and it will sharpen masonry bits should you ever need to. The 750's two "chucks" are cheap looking affairs having hardened sheet metal jaws. The rest of the machine is stout plastic and I don't mean this in a joking way. Many plastics are endure the rigors of the open shop better than metal if the application is selected with the material's characteristics in mind.

I have plenty of dull drills so I did not lack for demonstration material. The Drill Doctor sharpened a 1/2" drill spot-on and split the point precisely. I then used it to to drill a 0.503 hole in mild steel and it did so with two full width chips spiraling out of the flutes; a perfect textbook grind.

The Drill Doctor sharpened my test drills from 3/4" down to 3/32" and ground good concentric point on them both split point configs and regular grinds.

I sharpened my 3/4" and under drills with the larger chuck without trouble and they drilled on-sized holes.

The manual gives you clear instruction on maintenance and what signs to look for to determine wheel wear and how to flip the wheel over when the abrasive poops out. The manual goes on to say the little diamond wheel it comes with is good for maybe 200 drills. Only 200? In a busy five man shop 200 drills accumulate in the "sharpen me" coffee can in a week or two. Given that the replacement wheels cost $26, that alone brings into question whether the Drill Doctor is adequate for any but the small home shop. Well, that's how it's advertised and that's where I'd place it.

Drill sharpening can be a bafflement for people without good "eyeball" genes. In the Drill Doctor those running a home shop have a gadget available for a modest price which will keep the dull drill backlog to a minimum.

Small commercial shop owners better get the Drill Doctor's larger cousins because replaceing the litle diamond wheels will bust the economics justifying its purchase.

Adding from a later post:

Ensure the Drill Doctor chuck/cam units are correctly assembled so the jaws engage the slots in the thrust collar as well as the slots in the barrel. Mine were not and when I disassembled it for inspection and diagnosis I incorectly reassembled it in the same way it came from the factory. Without correct assembly it will not sharpen smaller drills so the point is correctly centered.

The spring jaws inside the alignment port sometimes hang up. Be sure to wiggle the drill while it's a bit loose in the chuck so the spring jaws in the alignment port index the drill in time with the cam in the chuck. Only then do you snug up the chuck.

Closely examine the clearance angle on smaller drills. I discovered on my unit the smaller the drills got the closer the as-ground clearance got to zero. While they cut they were slow to feed. I set the alignment adjustment lever to "+" to gain a bit more clearance and the drills cut better. This lever needs some intermediate positions.

There is a condition called "margin wear" (the skiny land where you actually measure the size) where the first 1/4" or so of the margin is worn under the drill's niminal size. The drill has to be cropped back to where the margin is unworn for safisfactory results.

Follow these steps not mentioned in the manual and you'll sharpen drills from 3/4" down to the 3/32" minimum so the points are accurately centered.

Sorry for my screw-up. I fully endorse the Drill Doctor as a drill sharpening asset for the home shop.



[This message has been edited by Forrest Addy (edited 01-07-2005).]

[George Seal]

Forrest,
I have had my 750 for several years and have not changed wheel yet. Replacement wheels are available at places like Harbor Freight for $19.00.
I dont remember if the instructions say it or not but when putting drill bit in the alignment fingers.Just snug up enough to hold the bit and lock it down after removing from fingers. I usually test bit after grinding to see if it cuts. It's not a Darex but nether is the price.
also the wheel is reversable giving you in fact two wheels.
It depends on how much the drill has to be ground to get back to sharp. A dull bit only needs light touch-up to go back in service, where one with a broken flute would take more grinding.
my $0.02 FWIW

------------------
George
Remember the early bird gets the worm, BUT it's the second mouse that gets the cheese.

[topct]

Forrest, I have one of those also. I found that by first tightening, and then backing off, while observing the chuck jaws, you can see them straighten out. I think the tendency is to feel that the bit needs to be tight in the chuck. I would say that 'just snugged' is adequate. Especially on the small bits where the jaws do contact the flutes. After a little practice however, I was able to sharpen the smaller bits.



------------------
Gene

[SGW]

Never having actually seen one of these critters...

Would it be practical to make your own double-angle collet chuck for smaller drills?

[J Tiers]

That is what I found.....OK on bigger drills, and bad or worse on the small end of the range.

After a certain amount of sharpening has been done, it gets worse than that.

I suspect that the sharpening wheel lasts far longer than the plastic chucks and the plastic tube they fit into.

[Smokedaddy]

I got one for Christmas too but haven't used it yet. BTW, a few weeks ago, I saw the 750 in a Sear's catalog for $107. I haven't seen the 750 anywhere close to that price.

Being a complete novice in machining, is there a way to modify or redesign the collet holding system? With all the talented machinist here I would think someone could come up with a pretty cool article for HSM.

-SD:

[Bruce Griffing]

I must be lucky - mine works well for small drills as well. I do have to be a little careful in the tightening torque and use the trick shown in the video to get the chuck "jaws" into a completely radial configuration. Other than that it works well even below 1/8". And I have sharpened many hundreds of bits and the wheel is still fine.

[JCHannum]

The worth/worthlessness of the Drill Doctor will probably be continued to be discussed as long as the merits of imported lathes versus used American. I can see us at the old machinist's home on the way to get our diapers changed loudly berating one or the other opinion firmly convinced that our's is the only correct way if only we could remember what it is.

I use a $2.00 General garage sale special mounted on the table of my T&C grinder when I have a drill that needs more than the eyeball method to sharpen.

These fixtures are probably as good as anything for drill grinding when set up properly. Used with a cup wheel, so the side of the wheel is not used, and provided with some simple, positive method of in & out adjustment, they perform very nicely.



[This message has been edited by JCHannum (edited 01-06-2005).]

[J Tiers]

<font face="Verdana, Arial" size="2">Originally posted by JCHannum:
The worth/worthlessness of the Drill Doctor will probably be continued to be discussed as long as the merits of imported lathes versus used American.
I use a $2.00 General garage sale special mounted on the table of my T&C grinder when I have a drill that needs more than the eyeball method to sharpen.
These fixtures are probably as good as anything for drill grinding when set up properly.
(edited 01-06-2005).]</font>

Yep. I use one of those "General Hardware" sharpening stands also.

I suspect the DD is actually a decent design, but that they are so inconsistent in assembly or part fit that some work fine and others crap out fast.

[John Foster]

I had trouble on small drills and a call to the company resulted in my getting a new 3/32 to 1/2 chuck. It was marked just like the one that came with the machine but close inspection showed a different cam slope. My complaint was lack of clearance on the small drills and this new cam slope seemed to help that problem. My 2آ¢ worth.

[brunneng]

I'd say my experience with mine pretty much mirrors the group. It is easier to grind larger bits correctly than smaller ones. I'd think that's partly because the chuck fingers have to extend farther for smaller bits and are less supported.

Actually to would be pretty easy to turn up a collet chuck using double angle or ER collets. The touchy part would be the cam surface that provides the relief grind. Come to think of it.. which I just did... you could use the original chuck to guide a cutter to cut the cam. A simple duplicator setup. Ok, maybe it's doable all around. Have to look at that. Sounds like a great article for someone.

Once you have that part made why not just make your own cup wheel grinder and take care of the whole shebang.

I don't have the 750. I have the one size down. How does it handle grinding the split point?

Kevin

[JRouche]

<font face="Verdana, Arial" size="2">Originally posted by George Seal:
It's not a Darex but nether is the price.
</font>

Well...it is but not as nice as their more expensive units.

I have used the 2500 model and it also uses sheet metal fingers to hold the bit although the body of the holder is metal.

I have the 750 also and had difficulty sharpening small bits.

I do have a cuttermaster with drill bit attachment but have yet to use it.

Unfortunately I tend to break more than dull my smaller bits (prolly breakin due to dullness), still gotta learn how to drill a hole. JRouche

[J Tiers]

<font face="Verdana, Arial" size="2">Originally posted by brunneng:


I don't have the 750. I have the one size down. How does it handle grinding the split point?

Kevin</font>

They are the same. In an attempt to help, DD sent me a 3/4 inch collet, which converted me from a 500 to a 750.

The split point would have benefited from a way to see the process. It is pretty much just wing it. You put the drill and chuck in, and whang it over into the wheel. With luck, both sides look the same.

Mine leaves a neat little rectangular point, instead of splitting, but then it sometimes splits the point right off. Same old looseness issue.

Its too bad the looseness and wear is as it is, the DD would otherwise be pretty nice. Loved mine for 6 months and 50 or 60 drills.