Why drill bit won't drill into wood?

[Outlawmws]

The op made 3/8" and even 1/2" pilot holes with similar "regular" point twist drill bits. He said they all penetrated easily (like pine wood) except for the new bit. The issue with bamboo isn't that it's difficult to penetrate with this type of bit, it's just likely to make a mess where it exits because it doesn't cut the fibers nicely like a brad point or auger bit would.

This says it all and the answer has been repeated several times, only few are actualy listening.

The Relief angle on that bit is wrong. Its riding on the TRAILING edge, and not the cutting edge, hence it doesn't cut.

Send it back and get your $$ back; its not even worth messing with.

 

[Rickss96]

The Relief angle on that bit is wrong.

Found this picture on another sharpening website that shows what Outlaw and others are saying - thought others miight be interested. Drill on right side is sharpened at too steep of an angle but it should cut wood.

 

[PoorOwner]

Well I got a refund and they told me to dispose of it
Should I attempt to learn how to fix this relief angle thing..
Got the holes drilled and mounted the vise already so not in too much hurry

 

[Toolfool]

Not saying this is OP's situation, just sharing a story. My neighbor once asked me where he should buy drill bits because his don't work. I stopped by his garage to find out he was trying to drill at the end of his spindle travel ! Moved his table up, and his bits work again.

 

[fatfillup]

Didin't read every post but one important factoid I learned at engineering school, before I switched to business is if you hold a drill bit, bolt or anything threaded vertical, and the threads go up and to the right, its right handed. If they go up and to the left, its left handed. Does not matter if its right side up or upside down. Very easy to remember and has helped me a lot.

 

[cheechi]

I would keep the bit and learn to sharpen it with a bench grinder if you have a good one. That size bit you will likely bog down any cheapo easily. There are a few youtube videos though I would look at a few in their entirety before you decide you have seen the 'right technique' because you can watch someone else do it right and not get close/zoomed enough to see that they're holding it backwards for example. Or pay a machinist double the asking rate if they will show you how to do it. Usually that works though not at all shops.

I am far from a master at it but I have successfully done it on a few of my throwaway bits to make them useful again. I own a drill doctor and it's nice and quick but it has its limitations. Worst case you turn your useless chunk of metal into a useless chunk of metal.

Didin't read every post but one important factoid I learned at engineering school, before I switched to business is if you hold a drill bit, bolt or anything threaded vertical, and the threads go up and to the right, its right handed. If they go up and to the left, its left handed. Does not matter if its right side up or upside down. Very easy to remember and has helped me a lot.

That sounds like some sort of rule.

Bamboo is pretty difficult to drill, you really should be using a step bit, forestner bit or ideally a specific bamboo bit (yes, they make drill bits designed just for drilling bamboo).

This is technically the right answer in general.

 

[zkling]

I'm still not convinced by that picture (due to angle/lighting/lack of rub marks) that the drill bit is really ground incorrect. Bury it in a piece of aluminum without a pilot hole, you will find out real quick if the bit is cutting properly or not.

The op made 3/8" and even 1/2" pilot holes with similar "regular" point twist drill bits. He said they all penetrated easily (like pine wood) except for the new bit. The issue with bamboo isn't that it's difficult to penetrate with this type of bit, it's just likely to make a mess where it exits because it doesn't cut the fibers nicely like a brad point or auger bit would.

The thing is though, not all problems in life are scale-able, particularly with cutting tools, they are more so exponential.

 

[LumpyMusic]

...Should I attempt to learn how to fix this relief angle thing..

Buy a DrillDoctor and sharpen your own bits. Ignore the chest puffers who incorrectly claim that they can do an "as good" or even "better" job with a bench grinder or belt sander. That's an impossibility.

Drills need to be sharpened no matter what their quality level or price point. Just like knives need to be sharpened.


Sgt Lumpy

 

[zkling]

If the relief angle truly is incorrect as some say, have fun regrinding an 11/16" bit with a drill doctor.

Amazingly drills were sharpened, resharpened and even re profiled on the fly long before drill doctors were invented.

 

[KenC]

If the relief angle truly is incorrect as some say, have fun regrinding an 11/16" bit with a drill doctor.

Amazingly drills were sharpened, resharpened and even re profiled on the fly long before drill doctors were invented.

there is more than one model of DD. Mine goes to 3/4". works good for larger bits, below 1/4, not so good.

 

[dogdog]

OP, just curious ... were you using a drill press with that bit ? I wonder how did you fit the bench top to the drill press ? Do you have an angle gauge to measure the angle? if it is 118deg as claimed ? a better pic of the drill bit with a shot of the camera facing the point. think that is better to see the angle, relieve cut then the side pics. to help dispel some mythical claims.

 

[dogdog]

there is more than one model of DD. Mine goes to 3/4". works good for larger bits, below 1/4, not so good.

think you are referring to the 750x .... still a pain to grind larger bits... not even sure if it fits like it claims.....

 

[Hemi49]

If the relief angle truly is incorrect as some say, have fun regrinding an 11/16" bit with a drill doctor.

Amazingly drills were sharpened, resharpened and even re profiled on the fly long before drill doctors were invented.

The most important knowledge to have whether you DD sharpen or freehand sharpen them is what your drill geometry should be.....If you don't have a clue what a properly sharpened drill looks like or what makes them cut you'll never be successful....
Hemi

 

[ttpete]

If the relief angle truly is incorrect as some say, have fun regrinding an 11/16" bit with a drill doctor.

Amazingly drills were sharpened, resharpened and even re profiled on the fly long before drill doctors were invented.

If the drill lips aren't of equal length, the drill will produce an oversize hole, and this is what happens to the vast majority of drills that are sharpened freehand. They're OK for rough work around the farm, but no good for accurate work.

Drill Doctors are manufactured by Darex, who also make toolroom quality drill grinders.

 

[LumpyMusic]

Amazingly drills were sharpened, resharpened and even re profiled on the fly long before drill doctors were invented.

And they were NEVER re-sharpened or re-profiled as accurately as when the machines were invented. Never.

Holes were bored before the invention of steel bits. I don't have any bone or flint broaches in my tool kit. Do you think I should get some because they were in use before modern steel bits were invented?

I do have an egg-beater hand drill. But I really prefer the DeWalt when I'm fabbing up a bumper or a roll cage.


Sgt Lumpy

 

[uart]

Well I got a refund and they told me to dispose of it
Should I attempt to learn how to fix this relief angle thing..

Yes. Don't throw it away, it can definitely be sharpened to a good workable condition.

Do you have a bench grinder? If so then take a look at a few youtube videos on how to sharpen them. If you've got any old or broken bits lying around then they are good to practice on. Cheap garbage Chinese bits are actually good to practice with as well. Be prepared to grind a few down to almost nothing before you really get the hang of it though.

 

[fatfillup]

If you don't have a clue what a properly sharpened drill looks like or what makes them cut you'll never be successful....
Hemi

That makes perfect sense and is why I have never attempted to sharpen one. I assumed there were things I didn't know to be successful.

One day I will take the time to learn. I have gotten good at sharpening chisels to the original profile but that took some practice.

 

[djjsr]

I would never use a standard twist drill like that to drill wood. Forstner bits and brad point bits do a much better job and result in a cleaner hole.

 

[creativecars]

I worked with an old school machinist. He could and did sharpen drill bits on a regular basis. I first started taking mine to him, he showed me some good techniques and now I can sharpen them to make them cut, but he was a master. No drill doctor in his shop.

Without really seeing the op's situation I wouldn't speculate a fix, but that bit should have no problem with drilling a few holes in wood. I use mine for similar purposes as needed.

 

[royesses]

Here is an illustration of drill bit angles and nomenclature.

 

[cheechi]

I would never use a standard twist drill like that to drill wood. Forstner bits and brad point bits do a much better job and result in a cleaner hole.

This is what I use for bamboo.

Bamboo isn't wood. However for drilling, bamboo is to soft and medium woods what stainless is to mild steel. You have to use harder drills, slower speed, and my experience is brad points help quite a bit if you don't have a good step drill.

 

[leg17]

I can imagine most machinists following this thread are shaking their heads.
The drill obviously has no clearance.
Since it was replaced for no charge, take the advice of others and watch some videos on drill sharpening. That should be a nice size to practice on.
It's not that hard with some practice.

 

[zkling]

If the drill lips aren't of equal length, the drill will produce an oversize hole, and this is what happens to the vast majority of drills that are sharpened freehand. They're OK for rough work around the farm, but no good for accurate work.

Drill Doctors are manufactured by Darex, who also make toolroom quality drill grinders.

Drilling by nature is not an accurate process, thus the invention of reamers, boring heads and the like. There are times when a slightly over sized hole is desired and thus hand sharpening asymmetrically is very handy. Like wise when special profiles are desired for drilling different materials. Spend some time in an old school tool and die shop, tool room or job shop, common practice.

Your argument is about as valid as saying that hand sharpened lathe tooling is not capable of producing accurate work.

 

[TomB19]

think you are referring to the 750x .... still a pain to grind larger bits... not even sure if it fits like it claims.....

I have the DD 750X and it sharpens 3/4" bits, no problem. If the tip has much damage, it takes freaking forever to remove much material but they come out sharp enough to perform surgery.

To the original poster... you do not need a special bit to drill bamboo. I'm sure there is a special drill bit for cheese, also. Pretty much any bit should drill bamboo. I've installed tons of bamboo counter tops and have never had an issue, other than bamboo blowing out terribly.

Oh yeah... spade bits in a powerful hand drill through 2.25" bamboo can break your arm, if not kept perfectly straight.. I suppose that's an issue.

Sharpen your bit to correct the relief. You'll be fine.

The procedure is:

- Drill all the way through the counter with a pilot hole (3/8", or whatever)
- Drill half way through with your 3/4" bit (don't go all the way through)
- Flip the counter over and drill from the back side

You should have a pretty clean hole but it will probably not be perfect, even drilling from both sides. Bamboo tends to tear, as much as it cuts, so a sharp bit is key.

If you're going to oil the top to protect it, you could oil it first and then drill. The hole should be a bit cleaner, once the oil has a couple of days to dry. The "chips" will come out more as granules after the top is oiled. It shouldn't blow out as badly.


Cheers!

- Tom

 

[TomB19]

By the way, I consider this sort of situation good justification for a Drill Doctor.

I've heard people tell me that sharpening bits is for apprentices and that they would never bother with it but by the time someone goes to the requisition counter, fills out an order, and gets the paperwork for a new drill bit filled out, I will have the bit sharpened, have the hole drilled, and will be onto the next paying job....

For my purpose, the convenience of a DD is tremendous.

 

[Hemi49]

By the way, I consider this sort of situation good justification for a Drill Doctor.

I've heard people tell me that sharpening bits is for apprentices and that they would never bother with it but by the time someone goes to the requisition counter, fills out an order, and gets the paperwork for a new drill bit filled out, I will have the bit sharpened, have the hole drilled, and will be onto the next paying job....

For my purpose, the convenience of a DD is tremendous.

All
I have a DD 500X.....I like it a lot.....But to be successful with it you have to know what makes a drill cut good and what makes a drill cut poorly......The DD is like any other tool; you have to spend some time with it before you gain proficiency.....

And yes, you can grind a drill off center with it so the drill will cut oversize.....
IMO, more people will be successful sharpening their drills with a DD than those trying to freehand them on a bench grinder.....
Hemi

 

[OccupantRJ]

Here is a pic showing what relief behind the cutting edge looks like on a twist drill. The steel scale is at the approximate relief angle. Let's see you sharpen this little boy in a drill doctor.

 

[Hemi49]

Here is a pic showing what relief behind the cutting edge looks like on a twist drill. The steel scale is at the approximate relief angle. Let's see you sharpen this little boy in a drill doctor.

??
I guess I'm missing your point?.....At least you seem to understand what relief angle is....Incidentally you won't sharpen an 1/8" drill in the machine that sharpens a 2"-4" drill.....I guess maybe you were saying every machine has an intended purpose?
Hemi

 

[Outlawmws]

I doubt a commercially available machine exists to sharpen a 3" or so bit. That would be fixtures, guides and using a traditional (if large) grinder wheel/belt. The factory might have such a critter, but that will be a one of a kind, not found in local machine shops...

Grind and measure, grind and measure...

The point made earlier on hand grinding tools is spot on. You CAN do it 'manually' without a drill doctor. You have to use other tools to ensure it's accurate. I have used an optical comparator to make sure tools were (hand) ground properly. it simply takes a bit of time. It can and has been done. (we won WWI & WWII without the drill doctor...)

 

[royesses]

Man sized drill doctor for up to 4" drills. Video on the linked page shows a demo. I would like to have one of these bad boys.
http://www.oliverinstrument.com/oliver600.html

 

[Outlawmws]

That ain't a DD, (but I am surprised to see commercial tooling for drills that size)

 

[Hemi49]

That ain't a DD, (but I am surprised to see commercial tooling for drills that size)

Funny, I was a production manager in a factory that routinely MACHINE sharpened twist drills up to 4" diameter....And had done so since WWII and earlier...The grinders were made by Heller...I still stand by my earlier statement that DD's are decent machines and have a place in anyone's workshop that uses twist drills...
Hemi

 

[Outlawmws]

I don't disagree Hemi; A DD properly setup and used is a good investment. I just don't agree it can't be done without one.

 

[OccupantRJ]

??
I guess I'm missing your point?.....At least you seem to understand what relief angle is....Incidentally you won't sharpen an 1/8" drill in the machine that sharpens a 2"-4" drill.....I guess maybe you were saying every machine has an intended purpose?
Hemi

That post was a little tongue in cheek, as I happened to pick up the drill to move it when it occurred to me that it was large enough to provide a sample of what we are talking about in relation to drill relief. It is mostly for the guys who may not know of what we were speaking. I have both an old school drill grinder, tool and cutter grinder, and also a Darex at work, and myself and the other machining foreman still prefer to sharpen by hand. Now, if I had time to kill, I would set up one of the grinders and grind all the surplus drills around so the less skilled individuals in the shop could make use of them more often.

 

[ttpete]

I doubt a commercially available machine exists to sharpen a 3" or so bit. That would be fixtures, guides and using a traditional (if large) grinder wheel/belt. The factory might have such a critter, but that will be a one of a kind, not found in local machine shops...

Grind and measure, grind and measure...

The point made earlier on hand grinding tools is spot on. You CAN do it 'manually' without a drill doctor. You have to use other tools to ensure it's accurate. I have used an optical comparator to make sure tools were (hand) ground properly. it simply takes a bit of time. It can and has been done. (we won WWI & WWII without the drill doctor...)

And we sure didn't win 'em with freehand sharpened twist drills, either. Dull ones went straight to cutter grind and were replaced with sharpened ones straight from cutter grind. All my working life, I took dull tools to the crib and swapped for sharpened ones.

 

[royesses]

That ain't a DD, (but I am surprised to see commercial tooling for drills that size)

Only joking about the DD. I recall seeing another large drill grinder but can't remember who made it. I'll bet the cost of those is very high.

 

[SweetD]

I have to say, for an amateur weekend warrior like me, the DD has come in really handy, and sharpens my drills incredibly well.

I was one of the people that lucked out on that DD Model 750X last year, where the DD company put out like a 50% discount coupon on that model by mistake, and then they honored it for those that used it.

Man I have really used that thing a lot. It works great.

Again, I am not in a commercial / professional shop. Just my own personal hobby stuff.

Dave

 

[pi_guy]

Bamboo is pretty difficult to drill, you really should be using a step bit, forestner bit or ideally a specific bamboo bit (yes, they make drill bits designed just for drilling bamboo). The drill bit you have looks fine, just the wrong tool for the job.

The bamboo drill bits you speak of are designed to work on non processed stuff. You want to drill a hole with out getting it to split in one of the nodes of the cane. I have the proper bits and a few other tools for bamboo & I have much growing on my property.
The table tops and other bamboo products are cured then split then dried. Before being processed into layers and pressed & glued together.
The best would be a wood style bit and brace or just use a hole saw the right size.

 

[uart]

Looks like the OP is long gone and now it's mostly just a debate about DD vs freehand sharpening.

I don't have a DD but I've seen the results with a skilled operator using one to do a split point, and it was pretty impressive. If I was to get one, being able to handle a split point would be a major incentive, as that's something I can't do freehand. The good models are pretty pricey here though, around $400 to $500 in stores. That's why I don't have one.

As for the results of off hand sharpening on a grinder, I know I can't get results that look as good as a quality factory sharpened bit, but I can certainly get good enough to drill satisfactory holes. And most definitely, I can get better results than the way many of the cheap Chinese drill bits that I've seen come sharpened as new.

Everyone should keep in mind that the OP was only drilling clearance (mounting) holes in wood, so we're not talking about holes accurate to 0.001" here!