PDA

View Full Version : Broken and Dull Drill Bits...



Jim Weatherford
11-15-2003, 05:17 PM
It seemed that every time I needed to drill a hole in anything, I could only find dull and / or broken drill bits in my drill index no matter how many or what type of bits I bought. Well I found a nice little "tool" that has now put an end to that problem (at least for the most part.

The "Drill Doctor" (DD250)(Post Tool $79.) is a very nice little portable bench tool that makes very quick work of precision sharpening your drill bits. There are larger and better models but this seemed best for my purposes. Check it out at https://www.drilldr.com/

It is simple to learn & use and totally accurate. It uses a built in jig for setting the bit at the right depth and angle in the jig and then the sharpening is accomplished by rotating the assembly by hand running the point against a diamond impregnated grinding / polishing wheel all guided by the assembly and rotating cam on the body and the hand held chuck. The finish is highly fine and accurate and the sharpening is easy to accomplish.

Now I can even re-grinding broken bits easily and quickly too. No, I don't work for them but it is a grat addition to your shop.

I havenít done a cost analysis, but I expect a rather rapid repayment, considering the last drill index I purchased was $64.(24 bits) and the last separate drill bits I purchased were $2.45 to $3.79 each for under 1/4" bits and I always purchased 5 to 10 at a time depending on the project, now it seems that I will only by 1 bit for every 10 I purchased before. A pretty good deal really.

GTsRFine
11-17-2003, 02:04 AM
I use the Drill Dr. and it is mostly as-advertised. It saves some time.
On the down-side - I do have problems getting the smaller bits to be sharpened correctly.

Jim Weatherford
11-17-2003, 04:03 AM
GTsRFine;

I understand your comment, but I've not personally come across that problemÖyet. I think that the alignment procedure becomes hypercritical as the bitís get smaller, that would make sense, but sharpening small bits by free hand is totally out of the question for me. The Drill Dr. helps to a very high degree, it's certanily not perfect, but it's better and easier than trying to do them by hand on a diamond or carbide lap. I know I tried, it wasn't a pretty picture and I didn't do it often.

I did however check angles and edge shapness with my Leica Stereo Zoom Microscope at 25X and it seems to be very close to the factory points and angles I compared them to and the overall polish was pretty good as well.

I was a forensic investigator and tend to be somewhat anal retentive about some stuff, especially when I spend $70. On a tool! LOL

Iím drilling aluminum and mild steel sheet and plate, fabricating parts and pieces for race cars from Vintage Lolaís to MGAís and crisp holes are a must, wondering drill bits are a bane to this work and I am really quite pleased, at least for now.

I also admit reluctantly (that's a manily joke thing about reading instructions; "I don't need no stinking instructions.") that I actually read the instructions and watched the video, then it took me the better part of an hour to get it all to work as advertised, even sharpened a few bits for my drill-hammer (masonry bits) as well.

11-20-2003, 01:12 AM
My wife got me one last Christmas and I love it. I had dozens of DULL drill bits. Christmas day I was out in the garage sharpening bits. It sure is great when you are in the middle of a project and the drill goes dull. Get the drill dr out and the jobs goes on without slowing down to a crawl.

I also had a bunch of masonry drill bits. It even sharpens them.

I haven't had any problem sharpening small bits down to the size they say is the smallest it will do which I think is 3/32"

I do a lot of woodworking and it gets used pretty often.
Bob Watkins

piman
11-20-2003, 03:25 PM
Hello all,

I'm in no way knocking the grinding jig, but for those of you who don't have one and have lots of blunt drills, try sharpening them free hand on the side of a smooth grindstone, it's really not too difficult even down to 1\8" or less.
Masonary drills are easily sharpened freehand, just be sure to use a silicone carbide wheel ('green wheel') not the more common Aluminium Oxide wheel.

Alec graemlins/cheers.gif

11-20-2003, 05:21 PM
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by piman:
Hello all,

I'm in no way knocking the grinding jig, but for those of you who don't have one and have lots of blunt drills, try sharpening them free hand on the side of a smooth grindstone, it's really not too difficult even down to 1\8" or less.
Masonary drills are easily sharpened freehand, just be sure to use a silicone carbide wheel ('green wheel') not the more common Aluminium Oxide wheel.

Alec graemlins/cheers.gif <hr></blockquote>

Some people can do it but I have never gotten a drill as perfect as fast as this thing does. It has just the right touch. It is not just going against the wheel, it rotates and goes into the wheel and changes angle in such a way you would never be able to duplicate by hand. At least I can't.
Thanks,
Bob

Dave Russell
11-20-2003, 06:54 PM
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by piman:
Hello all,
try sharpening them free hand on the side of a smooth grindstone, it's really not too difficult even down to 1\8" or less.
Alec graemlins/cheers.gif <hr></blockquote>
When I am in a hurry (read semi-emergency) I hand sharpen the drills. It DOES require a compound rolling/twisting motion which would be hard to describe. It duplicates the compound motion of the better drill sharpening machines.

The smaller the drill the harder it is to get the point exactly centered. I occasionally go through my drill sets & touch them all up on a good sharpener machine.

For those who cannot get the hang of the compound hand motion, the machine is far better.
D

piman
11-21-2003, 04:23 AM
Hello Dave,

yes, I agree with you and the easiest way to see what is required is to look at a largish drill and copy the shape. On very small drills the compound action is very difficult to achieve but in practice a flat face is effective and indeed some drills are manufactured that way.
I served an engineering apprenticeship some 35 years ago and such DIY tools were not available then so I have been hand grinding ever since.

I was trying to encourage someone who may not have sufficient use to warrant spending the money on the Drill Doctor but rather than replace blunt drills try sharpening them.

Alec graemlins/thirsty.gif

[ 11-21-2003: Message edited by: piman ]</p>

Dave Russell
11-21-2003, 04:51 AM
Hi Alec,
I understand what you are saying. For general purpose drilling I usually hand sharpen. As a machinist by avocation there is also a need for very precise drills when doing critical lathe & mill operations on such things as benchrest target rifles. The slightest off center sharpening will result in an oversize holes. For this work I use the compound drill sharpening machine.
D

piman
11-21-2003, 06:13 AM
Hello Dave,

Yes, again true, but that is getting away from the home hobbyist which is what most people here are. Those that are more professional don't generally require the advice anyway.
I assume you are well versed, then ,in off centre sharpening to give a larger hole if the correct size drill is not available?

Alec graemlins/cheers.gif

Jim Weatherford
11-25-2003, 03:16 AM
Honest, I tried to master the free hand sharpening method and I even had a diamond lap but for me the Drill Dr. was a quick fix, a no brainer for a mechanically challanger mechanical engineer. I'm certinally not hocking the machine, but it's pretty good and can easily pay for itself in a very short period of time. To grind or not grind... that is the question. Sorry and aplogies to The Baird.

aeronca65t
11-25-2003, 10:10 AM
I like using a drill sharpening fixture, but like some of the fellows above, I also will hand-sharpen in a pinch.
Anyway, on that subject:
A neat trick is to hand-sharpen a drill backwards (so that it cuts when the drill is in reverse). This is a great tool for drilling out broken studs or bolts, since the drill will usually "catch" at some point and spin the broken piece out. This often seems to work better than an "Eze-Out". Obviously this isn't good for drilling too deep (the flutes are all wrong). A left-hand drill bit is even better (but who has one of those handy in an emergency?)

Jim Weatherford
11-27-2003, 04:00 AM
Professor;

I like the backwards slant to remove broken cap screw or... I was given a set of Craftsman "Eze-Out" last Christmas only used the smaller one twice but they work pretty well and they really work on old brass screws. I re-mill lots of old wood and cutting trough old brass screws is a common experience though it's always a surprise if your not doing a good survey first then how do you remove them? "Eze-Out" to the rescue. I haven't used them on things like a Grade 8 cap scre or... but I'm trusting they will work as well, the data sheet that came with the set of "Eze-Out" suggested to drill a much smaller hole first and it doesn't have to be very deep just enough for the edge of the "Eze-Out" to get a bite, sounds logical.