[How do I?] Any tips for using the Drill Doctor x750?

[kd4gij]

I have had my 750 clasic for over 15 years now have sharpend thousends of drills with it. Simple easy to use.

 

[Mike Gibson]

I have a DD750 and it performed well for a few years and then it started to produce similar grinds as you describe. I opened it up and inspected for anything obvious. I did not find anything. I set it aside for the last couple of years but recently I got it back out and tried again. This time when I did the lip alignment I made sure the chuck did not turn to the right as I tightened the chuck. Worked great. I checked again and found there was a slight movement to the right. Now I know not to tighten without holding each end of the chuck.

I have an older model Classic Drill Doctor 750 and have found that many times it doesn't make the correct clearance angle when using the lips to position the bit. This tool ahs not been abused and only lightly used so I'm certain it isn't damaged. Whether this is a defect in the sharpener or or if it has something to do with the helix angle of the bits being sharpened, I can't say. I suspect that the helix angle of the bit would affect the position of the tip and hence the relief angle since the lips grip the helix to obtain the supposed proper position. For me, a work around for has been to use the lips to position the bit, do a trial sharpening and if the clearance isn't correct rotate the bit slightly in the holder and resharpen. Usually, with my bits I need to rotate clockwise but, again, depending on the helix, counter clockwise may also be necessary.

Perhaps the updated models have addressed this issue. I would want to know more before I purchased another as I am not completely satisfied with mine.

 

[Nelson]

A user named "EddyCurr" made a test of the DD on some bits over at HSM:

http://bbs.homeshopmachinist.net/showthread.php?t=51863&page=5


A neighbor's no-name 3/8" drill

​

Before beginning.

​

After a first pass. A check with a drill gage showed an angle of 122º
and a visual of the heel suggested the relief angle was shallow. The
width of the chisel edge measures 5/64" (1.98 mm).

The wheel is the OEM 180 grit. It leaves a coarse finish but it does not
have much use at this point. Perhaps after some wear knocks down the
high spots, the wheel will leave a smoother finish.

Some steps/facets are apparent. The expected result on the end face
running from the cutting edge to the heel is supposed to be one
smooth continuous surface. The trouble-shooting section in the
manual suggests the steps may be due to hesitant wrist action - I
thought I worked the chuck smoothly.

​

After a second pass.

Before continuing, I reduced the drill point angle setting so that the indicator
arrow was aimed at the base of the '118º' numerals instead of at the middle
of them. This change reduced the finished angle from the 122º shown above
to the desired 118º.

Also, during the step for positioning the drill in the chuck, I inserted the
chuck one notch CCW (to the direction of '+' on the sharpener) from the
straight up (12 o'clock) position. This increased the relief angle.

After resharpening to reflect these changes, a Split Points operation was
performed. As shown, I believe that the points are Under Split - too little
material has been removed to be considered an optimal result. The chisel
edge shown measures 1/32 (0.79 mm). Oh well, it is narrower than as
supplied new. Both cutting edges are equal in length.

The steps/facets are present again. If anything, they are more prominent.
I was consciously trying to be smooth. (I am thinking about applying
some kind of lubricant to the surfaces between the chuck and the
receptacle it rotates in for the next trial.)

The face shown in the right-most image appears dark as if over-heated.
This is just a result of lighting, it is bright to the eye.


More of the neighbor's drills

​

A 5/16" before beginning.

​

Notice that the finish is somewhat less coarse - perhaps due to some wear,
but also likely a result of reduced feed pressure.

Also notice that the steps/facets are gone. The machine had been operated
on top of a piece of corrogated cardboard on the bench - I saw that there
was some movement during sharpening and found that the faceting went
away when the machine was held firmly on a solid surface.

​

This is a 1/4". No 'Before' image, but the 'After' shows improved results, too.

Back on the surface finish.
.

 

[pdentrem]

It is important to be consistent on you part. I am still working on technic on mine.

 

[markbxr400]

Not a "how to", but a "what to" - most of my broken bits are small ones that I snap trying to go through relatively thin material. While I used to throw these away, now I resharpen. The stubby bits are much stronger than the long ones and have plenty of length left to make it through.

Mark

 

[randyjaco]

Nelson,
Change your wheels carefully. The height of the wheel is critical. The mandrel that holds the wheel is mounted to the shaft by friction and can move up and down on the shaft. If the wheel is to high or too low, it will give you fits in getting the bits to sharpen properly. I made a wheel height gauge and now use a wrench to twist off the wheels rather than pull them off or push them on.

Randy

 

[burnrider]

+1 on the drill doctor

I had one for a long time. Never figured it out, then one day took the time to play with it.

-Learn to put the flute vertical (narrow part) with the plastic splines at 12 and 6 o'clock before it goes into the gauge. Leave about 1/2" to start on a snug chuck for adjustment.

-For bigger bits, Make 1 turn. If the stone is cutting it at the top, step to your grinder with a protractor and take it closer to the 118 degree mark. Easier on the diamond wheel.

-After a few circles, re-gauge for length in the gauge and set the drill as needed.

-Clean with compressed air & follow up with spray silicone. Makes the plastic chuck smooth, and easy to operate.

-The stock wheel was #100 grit, seems to work well.

-Spent a lot of years free hand grinding the angles. It pays off when using the DD. I was close on a lot of drills, not as close as the DD.

 

[brasssmanget]

Very interesting thread. I've been debating getting a DD, since a lot of my drills are getting dull. I attempts at hand sharpening are hit and miss it seems, so I've been looking for affordable machines to make it easier. I have read elsewhere that these DDs are very hard to learn to use and get good results, so this information is very enlightening and encouraging.

 

[burnrider]

Very interesting thread. I've been debating getting a DD, since a lot of my drills are getting dull. I attempts at hand sharpening are hit and miss it seems, so I've been looking for affordable machines to make it easier. I have read elsewhere that these DDs are very hard to learn to use and get good results, so this information is very enlightening and encouraging.

3 of us (friends) who initially bought DD had the same experience. They tried it with no success, were intimidated, and set it aside. We have different levels of shop skill. If they saw it done one time, they could use it with confidence. I haven't cut the split angles to this point.

 

[Giles]

+1 on holding finger pressure (pushing the bit into the stop) on the drill shank as you tighten the chuck. When you pull the chuck out and are ready to grind, look at the chuck jaws from the rear and make sure they are not "leaning". If you over-tighten the chuck they will do that, and twist the bit out of position. Just loosen the chuck slowly until the jaws are all pointing straight into the center.

That is exactly the reason I exchanged the first the one I bought. The more expensive replacement model was no better.
I considered it an inferior design and returned it.
That was a few years ago and I would have thought they corrected it by now.
I found it much cheaper to replace bits smaller then 3/16" I can see how to sharpen the larger ones.
Some people love them but it was just a big disappointment for me.