have you ever had any luck sharpening drill bits? i know what you're thinking and we have a drill doctor at work, and it doesn't work worth a damn! i have better luck sharpening them on a bench grinder free-handed!

i'm actually getting fairly good at sharpning them, but do you guys have any tips? we have the appropriate stone on the grinder for drill bits, but beyond that...?

 

have a cup of water to dip the bit in to keep it cool while sharpening. and keep the correct angle. i think it like 30 or 40 degrees or something. if its to pointy it will dull quicker.

 

20 years as a driller building submarines. Maybe I can help. It would be a whole lot better if I could give you hands on but I will do my best.
First make sure you have the right grit wheel. Too course and the it doesn't give a good edge, too fine and it burns the edge quickly.
Second make sure the wheel is dressed. You want a straight face and square corners. I like the steel wheel dressers. Stone dressers make BAD dust. You should wear a respirator when dressing stones.
The stone for drills should only be used for drills. This will help keep a dressed stone in condition longer.
A good tool rest set at the correct height. The tool rest should extend past both sides of the stone. The table/rest should be at the center of the wheel.
Yes, you should have a cup of water to dip your drill in as you sharpen but this should be done BEFORE it becomes blue.
There are basically 3 different ways to sharpened a drill. Which one you use is the one that works best for you. I use the side motion to take down a drill quickly and the use a bottom to top movement to put my finish edge on. Some people use a top to bottom movement.
I will try to explain so you can try all 3 and see which one works best for you.
Now that you have a dressed stone and a properly setup tool rest you are ready to begin. This is for right hand people so lefties will have to adjust. :)
One of toughest parts will be to learn to have an even pressure across the whole pass. This will take lots of practice.
Put the index finger from your left hand and place it on the tool rest. Trust me it will hit the grinding wheel sometime or other and you will learn not to roll it as you sharpen. Place the drill on your finger using your right hand with the cutting edge straight across the center of the wheel. In a bottom (back) edge first movement move the drill down across the wheel. This is where that even pressure comes into play. A nice even pressure and it will be a light pressure. You will learn to increase the pressure over time and not over heat the drill. Keep the pressure even from bottom to top. Do this twice and now turn the over and do 2 passes on the other side. Doing the same number of passes on both sides with the same pressure will keep the sides even. Dip the drill in the water each pass. Check the edges of the drill as you work. The grind pattern will tell what you are doing. Any bluing and the drill is getting too hot. Less pressure, slower movement, dip in water more often. It will take a long time till you feel comfortable doing this but it's worth it. Okay, we will say you feel comfortable with the edges. Look at the drill sideways and make sure the back edge is lower than the front(cutting edge). It should be an even curve going to the back. The smaller you can make the this curve the longer the edge will last. Now you need to check that the drill edges are even. Take a scale/ruler with 64th" increments and place on the point and measure to the outside edge of the drill. If both edges are equal you are doing great. Also remember the point of the drill depends on the material you will be cutting. Look in machinist's handbook for degrees for materials and pictures of properly sharpened drills to guide you. (having fun yet?)
Once you have the edges sharp you need to "sharpen" the point. Basically you want to narrow it so it feeds into the material easier. Place the drill in your hand with the cutting edges up and down now turn it about another 10 degrees. With the cutting edge away from the wheel come into the edge of the grinding wheel and just grind the web (center part of drill) narrow. This will take a lot of practice to get used to. Turn the drill over and do the same on the other side.

I could go on and on but I think this should give you enough to start with. Let me know how you make out. I am sure if you do a search on the web you will find some good pictures to help understand some of the stuff I wrote.

Now some more important info about drilling. Don't have the drill spinning too fast. The proper pressure against the machine is about the most important part. Try to have the machine just about ready to stall but the drill is cutting properly. Use lubricant. They have some biodegradable stuff out now that works great. Make sure you have a good deep punch mark. That means a sharp center punch. :) The web of the drill should fit into the center punch mark. Example: You have a good deep center punch mark and your 1/8" drill web fits in it. You can drill all the way through but you should always go as deep as the diameter of the bigger drill you are going to use. This will cut down on the chance of th drill "walking". Let's say you are using a pistol drill. One hand should be running the trigger and the other hand should be behind the pistol. Many times people push the pistol with their hands on the sides and the stronger hand makes the pistol lean causing your drill not to go straight into the material. What I am trying to say is to have the hand that is pushing being at the back of the pistol so it will push on the drill.

When you get nice long chips out of the hole you are doing things correctly. Small chips mean many things from dull drill, not enough pressure, material too hard for the type of drill, drill is too hot plus some material only give small chips.

 

uh.......well my drill doctor is the shat. works awesome!

 

Was going to say... don't think I've ever heard a bad review about a drill doctor until you. Not saying your wrong... as I personally don't have one... but from what I've read they are highly recommended.

 

your not talking about me right?? Cuz i think drill docs are awesome. Had mine for like 6 years and works great on the origonal sharpening blades things.

 

Yep my drill doctor works great here also. If u dont set it up correcly then it will mess up the bit , but if u set it up right it sharpens them great.

 

WOW! that certainly is alot of info! i always keep the bit cool w/ water. i will give that technique a good try, i had to read it a couple times to comprehend everything.

i typically use a cordless or air drill, and i am careful to not over speed the bit. i put a needle valve on the inlet of the air drill to regulate speed, and i usually do run it just above stall. i have been using rapid tap cutting oil for lubrication/cooling the bits. i have a little contianer that i bip the bits in periodiaclly while drilling, works fairly well.

if possible i would like to see pictures of a few bits you have sharpened so i can try to mimic (a picture is worth a thousand words right?), if not, oh well.

the drill doctor i have access to belongs to the shop, i have no idea how old it is, if the stones are in good condition, and can only assume that because not only myself but no one else can get a good edge from it that i doesnt work properly.

 

Drill Doctors suck. We used some at work and they f'ed up the bits AND we burnt up the motor. Just do it freehand and save the money.

 

I was agreeing with you and saying the OP gave it a bad review. But appently there are lots of people who don't like them now that I've reviewed it a bit more. But anyway, looks like Victory shared plenty of info about sharpening them by hand... thanks Victory.

 

You are welcome for the info. I know it's a lot to digest but it isn't easy to explain so people can understand.
Check Wiki http://en.wikipedia.org/wiki/Drill_bit
I will try to get pics but it's tough to show the areas I want in a pic and get the right angle.
Yeah, most people freak when I take a new drill and go to put an edge on it. The drill is sharpened like a good knife so anyone can cut something with it.
Ask around and see if anyone has a Machinery's Handbook. I have the 16th Edition and on page 1525 is a great drawing of angles and shapes for sharpening drills. Just look under Tool Grinding if you have a different Edition.
For most people the "normal" grind will work. If you do a lot of drilling you need to sharpen the drill for the job you are doing.
One important thing to remember is when you drill aluminum use liquid hand soap with a little water added. Rapid tap and some others will work but hand soap and water are the best.

Well, I hope I have helped everyone out. I have never used a Drill Doc so I can't say one way or the other. Like most tools it has to do with how it's been taken care of and how one uses it. Sure I can sharpen a drill on a 4" cutting wheel while someone holds the machine but it doesn't do the best job.

 

drill doctors are ok (NOT GREAT) but ok. You still gotta take your time with them though

 

I'm a retired machinist. Victory is right. The only thing he left out is the correct angle of the cutting lip. It varies as he said but 90% of the time 59 deg on a side is the standard. Hand sharpening is a skill learned by instruction in person and then doing it untill you get it right. Many machinists can't hand sharpen drills. The split tip he described is hard to learn and requires a wheel with a very square dressed edge to grind the back of the flute away to thin the web. As he said the wheel has to be dressed perfectly flat and square to the sides of the wheel. It can't have any grooves in the face and it has to be dressed when it glazes over.

General tool co makes a drill grinding gauge that I used all the time. It has a set 59 deg angle and a scale to measure the cutter length of each drill flute.

I can sharpen by eye but prefer not to and most always use the guage. I have a drill sharpening device I made in 1968 that still works great for 1/8" to 1/2" drills.

The drill doctor is not real good but if that is all you have use it as instructed.

Machine shops don't use drill doctors, none that I have seen or worked in.

 

I have found, home made tools, made by highly skilled people are better than anything you can buy in a store. Its like aligning the front end on a ford twin I beam truck. Our old mechanic had a set of homemade tools, that would allign the trucks perfectly every time. where as the dealers and shops had a btch of a time. A bit off topic, but home made tools are the shiznit.