How to sharpen my drill bits...

[ersatzs2]

Went to Lowes to buy a new 5/8" drill bit and was shocked to see they cost ~$20.00 Well for $30 I see a delta power wetstone complete with water bath and adjustable tool rests, so I figure I'll get that and sharpen my old bit instead of buying a new one.

How did I wreck a 5/8" bit? drilling through the very thick stainless tops I got from bimmerpower with my trusty hilti mega HP 1/2" drill. Mounting up the new vise.

So now I have the thing unbacked and I'm looking at the bit with it's rounded edges and dull cutting surfaces thinking how do I hold this baby at the right angle to return an edge to the cutting surface? Someone must make a jig right? Or how about I drill a hole in a block of wood and rotate the bit in that while holding it against a tool rest? (how do I do that when my 5/8" bit won't cut paper right now?)

Anyone done this? Before I go home tonight and mess around and likely ruin the bit?

 

[Jbullfrog]

Look in the box, there should be a paper book that has pictures and words. Turn it until the pictures are right side up. Now, if you can't read the words flip it over to the side that says "English". There should be a section on bit sharpening that will give you the basics. $30 is a bit much, I paid $20 for a reversible Craftsman wetstone sharpener. Mine has angles marked on the table and grooves to align the tool or bits.

 

[Major Ramifications]

I love my Drill Doctor. It sharpens bits up to 3/4". It is very easy to use, and it is so nice knowing that every bit I pull out of my drill index will be razor sharp. And if I dull one while I am using it, in less than a minute it is sharp again. It can even split the points if you want (to keep the bit from wandering).

 

[1320stang]

Oooooh, it'll do split points? This is what has kept me from buying one, I love my split point bits.

 

[Abe]

The O.P. should have used a cobalt bit

 

[TNToy]

Nope. Well, that would have been okay. But it's not the reason the bit died.

Push hard, drill slow, USE CUTTING OIL, and bits last a long time, even in a hand drill. Running the drill wide open is the worst way to drill steel.

Shavings should be removed in a continuous curl, or very close to it. You'll feel the bit cutting continuously. You develop a feel for it after a while.

Use cutting oil, and if you see smoke, STOP. You weren't removing material quickly enough for that cutting speed. If you don't have any real cutting oil, use whatever's handy. Motor oil, 3-in-1. Whatever. It won't be as good, but it's much better than drilling through steel dry.

If you're not moving through the work fast enough, heat builds up from friction faster than the bit removes the heated material. You're effectively heat-treating (work hardening) the steel you're drilling, and also ruining the heat-treating on your drill bit at the same time. So the bit gets softer, and the steel gets harder.

There are 3 main reasons drill presses work so well on steel, and the bits last so much longer.
You apply much more pressure.
They spin slower (cheap ones are still way too fast)
The bit doesn't chatter. It's held completely stationary.

You don't need to drill a 1/2" hole through steel buy drilling 1/8" then 3/16" then 1/4" then 3/8" then 1/2". Even with a hand drill, it's best to drill, say a 3/16" hole and then switch straight to the 1/2". Stick your work in a vise and put all you weight on the drill, running slowly. The 1/2" bit will cut right through it.

Drilling a big hole with 8 different size bits and stepping up will ruin them all: All the force is concentrated on the bare shoulder of the bit, which dulls it more quickly, and makes it very prone to chipping off if the bit snags.

 

[wilbilt]

Some flavors of stainless are very hard. You didn't say whether you started with a smaller bit and stepped up to 5/8", or if you went with full grunt and 5/8" at the get-go.

I bought a Drill Doctor on clearance at HD about 6 months ago and am very pleased with the results. It has paid for itself twice over since then, in regard to new bits I didn't have to purchase.

 

[bmwpower]

Which Drill Doctor is the one to get? The 750?

 

[-lecroix-]

Ol' Machinist rule of thumb for pilot holes: 1/2 the diameter of the finished hole.

5/8" finished hole = 5/16" pilot hole
1/2" finished hole = 1/8" pilot hole
so forth and so on ...

P.S. Stainless is not really that hard ... but it work hardens really really easily, thus the reason for the dull drills. I spent 10-11 years machining nothing but 316 & 316L stainless for Parker Hannifin. Feeds and speeds are IMPERATIVE for the machining of SS.

 

[wilbilt]

Which Drill Doctor is the one to get? The 750?

The one I bought is the "XP" series, but came with the 3/4" chuck as a promo. At $60, I didn't think twice.

Yes, the DD750X would be the preferred model.

 

[Uncle Buck]

Ol' Machinist rule of thumb for pilot holes: 1/2 the diameter of the finished hole.

5/8" finished hole = 5/16" pilot hole
1/2" finished hole = 1/8" pilot hole We know you meant 1/4
so forth and so on ...

P.S. Stainless is not really that hard ... but it work hardens really really easily, thus the reason for the dull drills. I spent 10-11 years machining nothing but 316 & 316L stainless for Parker Hannifin. Feeds and speeds are IMPERATIVE for the machining of SS.

We know you meant 1/2" finished hole= 1/4" pilot hole

 

[TxDoc]

I have a 750X, too. Very happy with how easy, how quick and predictable it is. They have very good customer service, too. Go to the website to see the demo vids.

You can do 118 and 135 degree, and masonry bits.

I also bought mine off the website and they were running a special. You can buy a 500 and the larger capacity chuck, also.

Good luck on your sharpening.

 

[eschoendorff]

Nope. Well, that would have been okay. But it's not the reason the bit died.

Push hard, drill slow, USE CUTTING OIL, and bits last a long time, even in a hand drill. Running the drill wide open is the worst way to drill steel.

Shavings should be removed in a continuous curl, or very close to it. You'll feel the bit cutting continuously. You develop a feel for it after a while.

Use cutting oil, and if you see smoke, STOP. You weren't removing material quickly enough for that cutting speed. If you don't have any real cutting oil, use whatever's handy. Motor oil, 3-in-1. Whatever. It won't be as good, but it's much better than drilling through steel dry.

If you're not moving through the work fast enough, heat builds up from friction faster than the bit removes the heated material. You're effectively heat-treating (work hardening) the steel you're drilling, and also ruining the heat-treating on your drill bit at the same time. So the bit gets softer, and the steel gets harder.

There are 3 main reasons drill presses work so well on steel, and the bits last so much longer.
You apply much more pressure.
They spin slower (cheap ones are still way too fast)
The bit doesn't chatter. It's held completely stationary.

You don't need to drill a 1/2" hole through steel buy drilling 1/8" then 3/16" then 1/4" then 3/8" then 1/2". Even with a hand drill, it's best to drill, say a 3/16" hole and then switch straight to the 1/2". Stick your work in a vise and put all you weight on the drill, running slowly. The 1/2" bit will cut right through it.

Drilling a big hole with 8 different size bits and stepping up will ruin them all: All the force is concentrated on the bare shoulder of the bit, which dulls it more quickly, and makes it very prone to chipping off if the bit snags.

Very well said!

 

[Uncle Buck]

Another vote for the drill dr. I have the 750 and think it is great!

 

[Jbullfrog]

I have the Left-handed chuck for my drill doctor to do my backward bits. I found left-handed bits in my magnetic drill press to be great for extracting broken bolts. They usually spin out while drilling the hole before I have to get the extractor.

 

[79rallysport]

I have the drill doctor 750X or whatever it is and I bought it brand new. I can't say enough what a POS that thing is. I've followed the instructions to a T. I've tried all of the different settings and every time it is the same result, NOT SHARP. The bit ends up being only slightly more useful than a dull one. I've invested at least 4 hours to try to learn how to use the damn thing and its been nothing but a waste of my time and money.

The verdict is, if you need a sharp bit, buy a new one.

 

[bmwpower]

I have the drill doctor 750X or whatever it is and I bought it brand new. I can't say enough what a POS that thing is. I've followed the instructions to a T. I've tried all of the different settings and every time it is the same result, NOT SHARP. The bit ends up being only slightly more useful than a dull one. I've invested at least 4 hours to try to learn how to use the damn thing and its been nothing but a waste of my time and money.

The verdict is, if you need a sharp bit, buy a new one.

Wow. First negative I've read on the DD.

 

[mulepackin]

We know you meant 1/2" finished hole= 1/4" pilot hole

Don't be afraid to step-up a few times also, i.e. 1/2" finished =1/4" pilot calls for 1/8" pilot first. much less material to remove with each drilling thus less potential heat production. Much cheaper to replace a ruined 1/8" drill than 1/2" drill (bits to some).

 

[Uncle Buck]

Actually I have read alot of negative stuff about the drill dr. Most of the bad press I have found is usually on the machinist oriented web sites like the Home Shop Machinist, or The Practical Machinist, or if it is still active, the old Chaski Message board. If you go over there sniffing around long enough you will run into many complaints about the drill dr. I can see the frustration, it took me awhile to get any good results from the dd, and I still could not tell someone what to do. I finally started getting decent results, I just wrote it off as me being inept! Anyway, it does fine for me now, I just had quite a learning curve.

 

[Uncle Buck]

Don't be afraid to step-up a few times also, i.e. 1/2" finished =1/4" pilot calls for 1/8" pilot first. much less material to remove with each drilling thus less potential heat production. Much cheaper to replace a ruined 1/8" drill than 1/2" drill (bits to some).

I would second that idea, especially when drilling in harder material or very critical or sensitive applications.

 

[bmwpower]

I would second that idea, especially when drilling in harder material or very critical or sensitive applications.

+3

That's what I did to get through my stainess tops. I think I used 3 different bits in total to get to the 5/8" hole required.

 

[eschoendorff]

+3

That's what I did to get through my stainess tops. I think I used 3 different bits in total to get to the 5/8" hole required.

If you're gonna do that, why don't you just use a step drill bit??? The cheapo ones from HF work pretty well as long as you don't abuse them....

 

[ersatzs2]

Thanks for the wealth of information. Here is a summary of what I learned.

THINGS I DID WRONG:

Drill speed too fast.
Too many step-ups, (3-4)

THINGS I DID RIGHT:

Cutting oil. (benefit negated by drilling too fast)

NEW KNOWLEDGE FROM THIS THREAD:

I know stainless is not hard stuff, so was mystified at why it wouldn't cut. Great to learn it 'work hardens.' I guess the heat actually tempers it? That's what it felt like.

Stepping up size too many times destroys shoulders of each bit successively.

Drill at low speeds with lots of pressure.

Drill one pilot hole 1/2 size of finished hole.

When the work starts smoking, something isn't right

Drill Doctors are great. Or not. Or they involve a steep learning curve.

WHAT I STILL DON'T KNOW:

Am I wasting my time with this tool? It looks like a grinder wheel set in a water bath. I assumed I needed some kind of holder or jig, and in fact I see one on McMaster; has anyone used one of these?

 

[bmwpower]

If you're gonna do that, why don't you just use a step drill bit??? The cheapo ones from HF work pretty well as long as you don't abuse them....

Mainly because I didn't have one at the time.

 

[wilbilt]

I assumed I needed some kind of holder or jig, and in fact I see one on McMaster; has anyone used one of these?

I bought one of those from Sears in the 1970s. It was largely useless due to the setup involved. Talk about a learning curve...I gave up on it.

 

[Uncle Buck]

I bought one of those from Sears in the 1970s. It was largely useless due to the setup involved. Talk about a learning curve...I gave up on it.

The real problem with those is they do not accurately reflect the motion necessary to sharpen a drill bit.

For anyone who has ever been instructed in hand grinding bits, they will know what I mean. There is a special twist and turn of the wrist that the little fixture is not able to do.

It is similar to a saw that can cut straight, but not make a compound cut. It addresses one plane that needs sharpened, but not the other. Try as I might, I cannot hand sharpen a drill bit for nothing! Good thing I do not call myself a machinist!

Yes, you are wasting time and money with that deal, impossible to sharpen anything as it comes out of the box. Buy the DD master the learning curve, you will do alright, that is about as good as it gets for some like me!

 

[Uncle Buck]

If you're gonna do that, why don't you just use a step drill bit??? The cheapo ones from HF work pretty well as long as you don't abuse them....

I would not think of a step bit as a proper tool for any real heavy steel, or stainless application, best used on sheetmetal, or lighter applications to me.

 

[Uncle Buck]

QUOTE"I know stainless is not hard stuff, so was mystified at why it wouldn't cut. Great to learn it 'work hardens.' I guess the heat actually tempers it? That's what it felt like".

Some grades of stainless will rust, and some may not be the hardest material, but generally speaking many grades of stainless are harder material, and do machine with a greater degree of difficulty. So I would dis agree with the statement.

(NOTE TO SELF, USE MULTI QUOTE FEATURE NEXT TIME!)

 

[mulepackin]

If you're gonna do that, why don't you just use a step drill bit??? The cheapo ones from HF work pretty well as long as you don't abuse them....

Step drills are a great thing, especially for thin material and repetitive holes. You are limited in depth though.

 

[ersatzs2]

DRILL DOCTOR commentary!!!

Well, just when you have all convinced me to return my delta wheel to Lowes and buy a proper drill Doctor, I head to ebay of course. I find a couple dozen auctions, including one for a 750 with the following priceless commentary!!!

This "Drill Doctor" was worth twice or more what I paid for it. The Drill Doctor is an overwhelmingly complicated and thoroughly useless piece of ****. I was so frustrated in trying to make this thing work that it actually forced me to dust off my old Starrett drill gauge and an old metalworking text and spend the time in front of a bench grinder learning how to properly grind drill bits by hand. For this reason I will be eternally grateful and now it can do the same for you. I know you are asking yourself how can I part with such a valuable machine and that there must be something wrong with it, well there is, but that is the beauty of it. By literally forcing me to learn to grind by hand I now know how to sharpen bits in less time than it takes to remove the Drill Doctor from it's box and unlike the bits sharpened in the Drill Doctor they actually cut without chatter and without burning!

This Drill Doctor is used but it will "sharpen" drill bits every bit as good as it did when new.

Thanks for looking!!

 

[wilbilt]

I guess the only way you will know which way works for you is to try one or the other.

I have often ground bits by hand on a grinder with usable results, but for me the DD makes it easier, and probably more important...repeatable.

You could alway buy a Darex professional sharpening machine for big bucks, but the DD is a scaled down, consumer version of the Darex at a fraction of the price.

 

[comp]

best i can do is 1/3 normal is 1/5 drill doc

 

[MAD]

If you're gonna do that, why don't you just use a step drill bit??? The cheapo ones from HF work pretty well as long as you don't abuse them....

I agree the HF step drills are a good deal. I have used them a lot for light duty stuff like making holes for toggle switches and starter holes in sheet metal for a nibbler. This past week I needed to make a bunch of 3/8" and 1/2" diameter holes in some 3/16" steel for an air compressor I put together. The HF step bits zipped through cleanly with no problem and no sign of damage to the bit. I think I paid $ 9.99 for a three piece set of step bits.

I have had very good results lately sharpening drill bits on the disc side of my stationary belt/disc sander. This is much easier for me than my grinding wheel. I think having the table to steady my hand on is what makes the difference.

 

[engnerdan]

I have sharpened drill bits by hand and with the famed drill doctor. It may be quicker to do them by hand (after you have messed up many bits learning) but the drill doctor does a very nice job once you figure it out. If you read the instructions and learn how to set the bit correctly the drill doctor works. I don't own one personally but I am planning to buy one myself soon.

Dan

 

[TNToy]

What's been said about mastering the drill-doctor rings true. I've used a friends several times now, and would like one of my own some day soon. I sharpened an 18-piece bit set the first time I used it...

The first bit took 5 minutes to set-up and sharpen.
The second bit took about 1-2minutes.
I did the other 16 bits in less than a minute each.

Also, I can't believe this, but here's a use for a drill doc that no one mentioned: Restoring BROKEN DRILL BITS!

Snap a 1/4" or 3/8" bit in half? Take a grinder and bevel the broken edge all the way around, so that it roughly resembles a sharp bit... this saves wear & tear on the stone in the drill doctor.

Then just sharpen it like normal. It'll take a dozen or so passes to get a good edge, but it really does cut like a brand new bit. The super-short jobber length bit will also fit in really tight quarters.

 

[mike944]

I bought a drill doctor. It's ok. It's better than sharpening by hand for those of us who aren't experts at hand sharpening, but definitely nowhere near a factory point.

There's definitely a learning curve for the DD, and it works better when the grinding wheel gets worn down a bit. It's a little too coarse right out-of-the-box.

My advice? After using the DD, finish up the edge with a couple of strokes over a diamond honing stone.

My biggest complaint is how it splits points. Not very well. It's not too bad on larger bits, but forget about it on smaller ones. The corner of the wheel isn't really a sharp enough corner to do it properly, it makes a split point with a rounded internal corner.

I think a drill doctor would be great if it had a better grinding wheel inside of it.

 

[Rusty67]

After installing a LCD TV yesterday I realized that a lot of my drill bits are not that sharp. I'm wondering what is better, a Drill Doctor or some sort of wet cuting system. Wouldn't a wet cut provide protection against heat build up on the bit making the bit brittle ? Am I just worrying too much about something like that ?

Also, if I do get a DD, is the only difference between the 500 and the 750 the larger chuck ?

 

[Uncle Buck]

After installing a LCD TV yesterday I realized that a lot of my drill bits are not that sharp. I'm wondering what is better, a Drill Doctor or some sort of wet cuting system. Wouldn't a wet cut provide protection against heat build up on the bit making the bit brittle ? Am I just worrying too much about something like that ?

Also, if I do get a DD, is the only difference between the 500 and the 750 the larger chuck ?

True, the 500 allows you to sharpen up to 1/2" bits and the 750 allows for up to 3/4" bits. If you are thinking of buying one avoid the model under the 500 size; with that model when it comes time to replace the grinding stone you cannot simply buy the stone and do it yourself, instead you have to pay to ship it back to the factory then pay them to replace it for you!

 

[jimvannoy]

I have a Black Diamond Drill Grinder. Got it in a package deal with other equipment a few years ago. It works great.

 

[old salvage]

I've had a Drill Doctor for 3 yrs now and dont like it. It does not consistantly taper the heel of the bit. If I sharpen 4 or 5 bits on three of them the heel will be the same height as the cutting edge. Did what the stupid manual said to do to remedy the problem and its still defiant.