Drill Bit Sharpening

guido

Well-known Member
Hello

Some of you use the drill doctor to sharpen bits.
how good does it work? I have been using my old grinder with some success. Now with the new bench grinder and a tool rest much better results. The lager lighter bit is 1/2 in, never sharpened. The smaller blued one as seen a few sharpening,

Guido.
a170452.jpg

a170453.jpg
 
Bought a 750X a couple years ago. Read the manual, watched the video and it worked satisfactorally. A few months later, I wasn't getting good results at all. Re-did the manual and video thing and still not good. Dug into it again about a month ago. Even worse results. I am trying to do it free hand on a grinder. I would like to find a bit gauge to use as a guide. So far I am supporting the new bit market.
 
I freehand grind all my bits but the smallest from a 1/4" down.
for the 1/2" and up i use a drill angle guide with graduations, the rest i just eyeball.

Practice makes perfect,...i'm almost there :wink:
 
I sharpen all but the tiniest ones by hand. A neighbor I used to work with several years back had a "Drill Doctor." I assume it was one of the early ones. I was impressed with how well it worked.
 
Hello TWheat,

I do them by hand. Learned how to from a machinist. I use the grinder's tool rest set at an angle, and use the face of the wheel. I'm able to do all the 64Th set that way. Small one are getting smaller by the day! HA!HA!,


Guido.
 
Hello Bob Bancroft,

I do the little ones too! But they are getting littler as we speak!

Guido
 
Hello bison,

I have been practicing for awhile now. I find the 1/4 in and bigger a little easier to do.
Like you said they don't have to be perfect,
But it helps if they are, HA!~HA!

Guido.
 
I have the Drill Dr. 750x and like it haven't had any trouble with it. I sharpened all my drills by hand even # 51 drills we used for tag nails until about 15 yrs. ago or in my forties. I was tool room machinist at the time.
 
The bottom one looks pretty good but because it's been sharpened a few times you need to thin the web, the little straight part between the cutting edges. As you sharpen back the web gets wider and makes it hard to push. I learned early in my apprenticeship to hand sharpen drills and have been doing it ever since.
 
Hello Mike(NEOhio),

The drills have different twist, so the trailing end will be wider where there is more twist per inch. I could trim that part, but it only goes along for the ride. The one I sharpened is 119.5*, it should be 118* like the new one.
So I need to fine tune the grinder's rest,

Guido.
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It might be camera angle, but the one in the top pic seems to be sharpened correctly. I met a man once who bought used drill bits from several factories. He sharpened the bits himself and traveled some states in the midwest selling the sharpened drill bits to shops and farmers.

He showed me that the should behind the cutting age had to drop some so that part of the bit did not let the bit run around in the hole. I've seen some bits that have been machine sharpened that looked okay, but I've also seen some that were not sharpened correctly.

I sharpen drill bits myself just using my eyesight - works for me.
 
Hello Dick2,

The bottom one is a lot smaller. Top one is new. The bottom one is between 1/4 and 3/8 IN".
I measured the angle and it is 119.5*. It should be 118*. I need to fine tune the grinder's rest,


Guido
 
Hello Dick2

Here is a better comparison. The angle is pretty close, 119.5* the one I sharpened, and 118* the new one. Both bits are the same size, but the twist is not,

Guido.
a170476.jpg
 
(quoted from post at 13:50:20 10/01/14) Hello bison,

I have been practicing for awhile now. I find the 1/4 in and bigger a little easier to do.
[b:437de159c2]Like you said they don't have to be perfect,[/b:437de159c2]
But it helps if they are, HA!~HA!

Guido.
Hey Guido,...i didn't say the bits didn't have to be ground perfect, cause they do if you want to drill a hole fast and of the proper size and doesn't wander.

I said "[b:437de159c2]practice[/b:437de159c2] makes perfect" :wink:
 
If you want a guide for the angle, put 2 hex nuts side by side. Gives 120 deg angle between the two nuts. When working freehand, you can vary the angle for the material you are drilling. Less point for harder material.
 
Hey bison,

I get it. I have been practicing since I was thought. The fellow I worked with was a machinist.
Left that job were we both worked in 1972. I have been practicing ever since, far from being perfect though. Have a good day..........

guido
 
Hello moresmoke,

I set the grinder's tool rest at 38* lower then horizontal. I'm not sure if the bench or the grinder are 100% level, probably not. I just leveled the protractor bubble, and the scale read 38* The resulting angle for the bits turned out to be 119.5* I was shooting for 118* so I got close. I'll set the tool rest @ 40* and see if I can come up with 118*. I have more bits I can practice on... practice on.. practices on..

Guido.
 
Hey Guido, I bought a set of drill bits 1/16 to 1/2" from an outfit in CA.
Lifetime warranty against breakage.
If one breaks, one ph call and they send a new one free of charge.
I can drill trough a spring steel or stainless no problem.
they eat trough grade 8 like cutting trough butter.
Set was $300,..After using them for 2 years i have to break or sharpen one yet.
 
My first part-time job during college was in a machine shop. Learned how to sharpen bits with a hand guage....bought one at Sears for under 2 bucks- still use it 47 years later. In Ag Engineering class we made our own, but it had no gradations, so wasn"t worth much, just had the correct angle.
 
Trying to sharpen a bit without a gauge is wasted effort. Both sides need to be the same angle and SAME LENGTH. The cutting edge has to be measured if you want to cut a proper sized hole.

I have DD 750X. It worked great for years, not so much now. I have to find time to tear into it and see what happened.
 
There is alot to it. If your tip becomes off center your hole will be bigger than the drill diameter.There are books on the subject. I use the Darex . Ive seen toolmakers make them sharper than new by hand , I just never practiced enough.
 
Hello dr sportster,

Been practicing since the very early seventies.
I think now its time to put the practice to good use. You should get curls,both the same size, on both sides while drilling. As you know, a sharp bit is only part of the equation! My next project.
They will be sharp when I get done........

Guido.
a170565.jpg
 
Hello JMS/.MN,

You got me by three years. The machinist that showed me, did it in 1970. I still use a hand gauge for the final angle check.
I came up with 119.5* with the tool rest @38*.
If I go to 36*, on the tool rest, I should be even closer to the desirable 118*. Got more bits to do so I'll try that. Although the 1 1/2* more is really not much. If you look real close were it says taps, there is a box full of bits, my next project,

Guido.
a170566.jpg
 
With big drills I've sharpened them, then try drilling at slow speed. If one side is cutting more than the other it's back to the grinder to take a little more off that side.
 
(quoted from post at 11:49:09 10/02/14) Hello dr sportster,

Been practicing since the very early seventies.
I think now its time to put the practice to good use. You should get curls,both the same size, on both sides while drilling. As you know, a sharp bit is only part of the equation! My next project.
They will be sharp when I get done........

Guido.
a170565.jpg
e telling me you dulled every bit in that bunch?:shock:
In the sets 1 have I bet half the bits have never been used yet, and i have been drilling holes for 40 odd years :lol:
 
Hello bison,

I have used not only the full 1/64/ set. but many odd sizes. Helicoil sets require some odd sizes as well. Unless the drills are cut for the chuck, all of mine bare marks of slipping. Never seams tight enough to stay tight,

Guido.
 
I never use helicoils, i think they are kinda useless.
If you have to drill and tap for the coil one may as well forget the coil and tap for the next size bolt in either metric or standard,..whichever comes the closest.
It's cheaper and stronger.

PS,..get yourself a new chuck with key.
I never had much luck with these keyless chucks to hold the bits from spinning.
 
Hello bison,

I've used them to repair many stripped holes on aluminum bell housing, bringing the size to the original 7/16. I think the material is 18 8 stainless, better then new. There are other styles of inserts that use regular threads as well. I still have some left from my wrenching days. They work just fine...

Guido.
 
Brand new key chuchs never held either except when you want to get the bit out and can't
 
Don't get too carried away with that one general purpose angle. Drill presses and lathes are different than what you use in a hand drill. Material matters also. Check the options in an industrial supply catalog.
 
i use a drill doctor. it works good on 5/32 and larger bits. I have trouble getting the smaller bits set up in the chuck correctly.

The only thing I don't like about the drill doctor is some of the bits will leave a rough edge around the hole.
 
Hello tractorguy2,

How about a broken bit. Does the drill doctor work on them?

Guido.
 
I was given a new drill doctor and found it SOMEWHAT useful. Took it back for refund.
With a little practice, this has worked for my bad eyes and shaking hands. I even modified it to sharpen 1/16" bits--Now that was a challenge!!
mvphoto11649.jpg
 
Hello jiles,

Can you sharpen broken bits with that tool?
Is the bit sharpened from the front of the wheel.
I've seen attachments similar to that one that uses the side of the wheel, not my first choice!

Guido.
 
(quoted from post at 19:42:39 10/03/14) Hello jiles,

Can you sharpen broken bits with that tool?
Is the bit sharpened from the front of the wheel.
I've seen attachments similar to that one that uses the side of the wheel, not my first choice!

Guido.


Many years ago I learned to never use the side of a grinding wheel unless it was rated for that use. Today you see/hear of using the side of a grinding wheel often. Are all wheels rated that way today?

As for sharping a broken bit, just free hand grind it to what it should look like, then finish it on a Drill Doctor or that drill sharping tool shown.

I like my Drill Doctor.


Dusty
 
Hello Dusty MI,

You and me both. Never use the side of a grinding wheel, unless was designed for that purpose. Have you ever seen this drill doctor? 3/32 to 5/8 IN. capabilities,

Guido.
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Hello tractorguy2,

I have many times, with mixed results though,

Guido
 
As retired Machinist, it is my personal opinion that the side of a grinding wheel can be used for sharpening a drill bit.
However, common sense must be used along with other considerations.
Only [b:6336a6e20a]LIGHT[/b:6336a6e20a] grinding, should be considered and the fact that the side surface, in many cases, is not perfectly flat.
Side surface will eventually [i:6336a6e20a]"glaze"[/i:6336a6e20a] creating more heat to the object being ground.
I use a diamond point dresser in a special holder, to clean/true, the side as well as the front surface of the grinding wheel.
I would [b:6336a6e20a]NEVER[/b:6336a6e20a] use the side of a grinding wheel for heavy grinding unless it is designed for that purpose!
 
Hello jiles,

Common sense is the key word, but not always practices. The drill sharpening in the picture is from a 1963 lathe operation book.
I have seen guys use the side of a valve grinder's wheel. Again common sense ruled then.

Guido
 
Look up this simple tool gauge for sharping drill bits.

General Tools & Instruments 16ME Multi Use Rule and Gage by General Tools &
 
Hello Dusty MI,

Here is what I have been using. Thanks for the

info.....

Guido.
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