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wrecked bitWhen fastening 2x lumber I keep grinding down the bits. I predrill a hole and a push hard as I can on my hammer drill but still wreck the bit. I'm using 2.5" gold screws. Can anyone help with a better screw, better drill, better bit, or better technique?

UPDATE... Thanks everyone.

  1. I learned the difference between hammer and impact and have switched to an impact for screws.
  2. I am starting to use Roberson and square head fasteners and the difference is amazing.
  3. I felt wasteful going through the Philips bits but they sure are cheap in bulk and the old ones can be used as pins/rivets or tossed in the recycling.
  4. A bit of beeswax or petroleum jelly on the screw sure makes the 2.5"+ screws go in smoother. Thanks again!
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    Is that a rotary hammer? not the sort intended for masonry? Pozidriv or Robertson (depending on country) would probably be more effective than Philips. – RedGrittyBrick Dec 20 '15 at 20:34
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    Lots of good advice below. If those gold screws are from evil orange (HD), they are one of the worst screws I've had the displeasure to use. Sloppy machining on the heads mean lots of slipping, even when using an impact driver. Hammer or spin mode on a drill would be way worse. The painted gray philips exterior screws at HD are better (as are any of the alternate heads as described below). Using an impact driver would be better as well. One last technique thing: if you're not absolutely perpendicular to the screw, you'll get way more slipping. – Aloysius Defenestrate Dec 20 '15 at 23:28
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    Those DeWalt bits are not very good at all. I've had good luck with bits made for impact drivers because they are made from a harder material. – JPhi1618 Dec 21 '15 at 15:34
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    I'm always amazed that Robertson never caught on in the US. I'd probably go crazy trying to do framing or assembly with Phillips screws. In addition to not slipping, a Robertson screw can be pegged onto the bit and will stay there - you can set the screw into position and drive it in with one hand after that. – J... Dec 21 '15 at 17:48
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    @dongemus Can you please show us a photo of the head of the screw. That screw looks like (the screws we get here in NZ, which are) a pozidrive screw. You have a philips bit which is not the same. A pozidrive screw has 4 extra little star points, & the bit has 4 extra flutes. see this image dahle-verbindungstechnik.de/media/catalog/product/cache/1/image/… If you can get them a robertson (square hole/bit) screw is in my experience much nicer to work with. – DarcyThomas Dec 22 '15 at 3:57

11 Answers 11

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This is an extremely common phenomenon and there's nothing you can do to prevent it entirely.

You seem to be well aware of the standard bit of advice going back to the days of slotted screws, that it is vital to press hard to fully engage the driver with the screw. But unfortunately with power driving and Phillips-head screws it is virtually inevitable that you will experience the head slipping out at least some of the time (called 'cam out') which will always cause some damage to the screw, to the screwdriver/driver tip, or quite commonly, both.

Why is it so easy? The ugly fact is that Phillips screws were purpose-designed to cam out!

They were not intended to become consumer-level fasteners but rather were for industrial use, the intent being that on production lines where speed was essential the driver should cam out rather than risk the screw being over-tightened, to prevent them being set too deeply, or snapping. And also to help reduce wear and tear on the power drivers themselves (the motors and gearing, not the driver tips — these are a cheap consumable in industrial settings, literally available to buy in boxes of 100 and more).


Edit: provided by the Comments below, Phillips screws being designed to cam out is apparently a persistent myth, the result of a misunderstanding based on the different use of the term by Phillips in his patent application (Phillips 2,046,837) and in modern usage.

The patent application actually states that the design intention was the exact opposite, particularly in the context of power driving, going so far as to claim:

"Moreover, by reason of the perfect fit between the driver and the screw, the screws may be driven and removed innumerable times without the slightest indication of mutilation to the head."

Now this may be true if both driver and screw have perfectly matching geometries corresponding with the patent but unfortunately in the real world, for whatever reasons, Phillips drivers do cam out very easily and begin to strip the screw (even without a power driver being used).


The problems associated with them led directly to the development of Pozidriv, a linear descendent of the Phillips head designed to have the same benefit (auto-centring) but by providing more facets the tip of the driver engages much better with the screw, and as a result it will cam out far less easily.

So if you need to continue to use Phillips screws buy your driver tips in bulk and simply throw out the stripped ones as soon as they're too worn to work well. But ideally if possible switch to better screws: Pozidriv, Robertson or Torx.

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    Torx all the way! Or square drive...not a big fan of Pozidriv. – grfrazee Dec 21 '15 at 4:06
  • @grfrazee, I don't think Pozi is totally brilliant myself, but I like them well enough, as long as the driver and screw are matched for size. Wish I could get Robertson here, they would be my go-tos given the choice. Almost no Torx here, tend to be seen only in electronics and on some tools. – Graphus Dec 21 '15 at 13:12
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    The claim that it was designed to cam-out appears to be unsubstantiated. Apparently Phillips did use the word "camming," but in relation to dislodging any foreign material in the screw, not in relation to the modern term "cam-out." WP cites this PDF. Still a good answer, though. – T.J. Crowder Dec 21 '15 at 13:40
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    @Graphus: Oh, absolutely. I can't stand Phillips. But the claim that it was designed to do that (as opposed to designed to make it easier to dislodge foreign material) doesn't appear to be supported. – T.J. Crowder Dec 21 '15 at 13:48
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    @Graphus TJ is correct. It is one of those ongoing rumors we should dispel. Just in case wiki changes around, source was 2.1.1.1 of scholar.lib.vt.edu/theses/available/etd-42698-205111/… with patent links. – Jason C Dec 21 '15 at 15:17
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Unfortunately, the angled tip on Philips bits causes them to climb and slip, and round over their edges and/or strip the head of the screw. Often if you buy a pack of screwdriver bits for your drill, it will come with lots of #2 Philips bits because everyone knows that perhaps the most ubiquitous head and size, and at the same time it is very prone to getting rounded over.

In my experience, using an impact driver helps, as well as predrilling the holes (though you already mentioned you're using a hammer drill and predrilling).

An even more effective solution is to switch to screws with a different type of head. Robertson (commonly called "square drive") and Torx ("star") bits extend straight down into the screw head rather than angling down into it, so they do not climb or slip out of the screw head very easily. These types of bits engage much more securely with the screw head and are much less likely to slip than a Philips bit.

Another interesting screw head, the Outlaw, was developed in the past few years which promises to eliminate stripped screws and bit changes. It is basically a series of concentric stepped Allen/hex heads. Because smaller screws only engage with the smaller steps on the screwdriver bit and larger screws simply engage with more steps, you don't have to change bits when working with different screw sizes. Unfortunately, at present these screws are somewhat of a specialty item, they are currently only available in deck screw sizes (as of December 2015), and cost more than twice as much as similarly-spec'd Torx screws.

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    Hammer drill and impact drivers do two, very different jobs. Using hammer mode for screws isn't really going to help because it only "hammers" when turning. When driving a screw, you need the "impact" at zero or low speeds, which is what the impact driver provides. – JPhi1618 Dec 21 '15 at 18:51
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Another thing that might help: although the brand of goldscrews that I use are described as being waxed/lubricated, for demanding jobs, or to max out cordless runtime, I use a smear of petroleum jelly or wax which eases insertion. I keep an old candle stub for this purpose. I feel that p. jelly is a better lubricant but a bit less convenient. It also gives an added degree of rust inhibition and makes removal a bit easier.

  • I tried beeswax based on your recommendations and I couldn't believe how much easier the screw drives, thanks! – dongemus Feb 10 '16 at 2:02
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Hammer drills are designed for working with masonry. Since you're driving the screws into lumber, you really don't need the hammer action for this job. Switch to a standard drill (or, if your hammer drill allows you to disengage the hammer action, do that) and lower the clutch setting to the lowest value that will get the screw head down to the wood surface. You can start by dropping it to the lowest setting, then raise it one step at a time if it doesn't drive the screw in far enough.

Here's an excerpt from Clutches, torque and you on the HomeImprovement.SE blog - which pretty much describes your exact situation:

On a power drill, the clutch setting is the amount of torque that the motor will pass through to the bit. With the setting at 1, it will pass very little power, and at the maximum setting, it will pass the most. Some have a numerical scale, 1-5 and then a symbol for a drill bit. In this case, the drill bit completely disengages the clutch, it will always pass the maximum amount of power.

torque adjustment on a power drill

So, you’re asking yourself, why would I ever want to use less power than I have available to me? Didn’t I buy this awesome drill for all the power it has? Well, the answer is “sometimes”. A common time you would want to dial this down is when driving Phillips-head screws into wood.

Let’s say you put your drill on maximum torque and drive that screw all the way in. When the screw reaches the depth you want, a couple of things might happen – 1) You might over-drive the screw. Remember, you’re on maximum torque and wood is generally soft. So you might put that screw in a bit more than you wanted, especially if it’s soft wood. 2) You might start stripping the head if it’s hard wood as the bit cams out of the head. Phillips-head screws are made to cam out, but this was in the days before there were torque limiting tools. The bit will rise up and out of the screw to avoid shearing the head off of the fastener. However, nowadays you’re most likely to just strip the screw slots and make it impossible to remove.

However, if you put it on one of the lower settings, the clutch will not transmit any more power to the bit once the power needed to turn the bit is more than the setting. More than likely, when driving our screw into wood, you want to set the clutch number at the number that will cause it to stop when the screw head reaches the surface. You’ll probably want to start low and maybe turn up a notch or two if it stalls out before the job is done. But when you have it right, you’ll have the best of both worlds – getting your fasteners all the way where you want them without having to worry about stripping the head because you didn’t let go of the trigger soon enough.

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Posidriv is a big improvement on Philips. No experience of the others. In the UK I think Posidriv is the most common for construction, with Torx etc for specialist applications.

I use Wera Diamond bi-torsion bits - last longer than others I've tried. (Their blurb: "Bi-Torsion screwdriver bit , BDC series diamond coated. Colour banded for identification. The coating helps prevent cam out damage to the head of screws. The material used also ensures longer life span."). There are probably others similar.

Assuming your screws are good quality (In UK I use Goldscrews from Screwfix & they're good. Not sure if it's a brand or a generic term?)

To some extent, you have to accept that bit-consumption is a fact of life. You've got DeWalt ones there so they're not rubbish. & should last a while.

You're not using your drill on "hammer"? Should be rotary only for screwing. Just checking.

The other thing is SPEED: keep your speed down - this is why there are dedicated drivers - their gearing is lower than a drill. If you have a variable speed drill, use a light touch or you'll destroy even the best bits.

Also set the clutch (if your drill has one) a bit lower than you think you'll need.

Or consider buying a driver/combi (latter has a low speed setting as well as variable speed). Or you could consider the latest & greatest - an impact driver (eg https://www.youtube.com/watch?v=O9syKDhdUos). Others are available.

  • I have to disagree. Those particular DeWalt bits are pretty terrible. They're soft and don't last long under the best conditions. – JPhi1618 Dec 21 '15 at 15:32
  • Re dewalt bits, I stand corrected. Never used them personally, just assumed from the name. Can't be worse than a "trade pack" of unbranded bits though surely? – user3418765 Dec 21 '15 at 17:51
  • Yea, unfortunatly, DeWalt has put their name on a little too much these days, so sometimes it doesn't mean much. For consumables like Phillips bits, I put them into the "good quality, but ordinary" category. Mid-tier. Room for improvement. I say terrible for a job like driving 2.5" screws, but competent for many lighter jobs. – JPhi1618 Dec 21 '15 at 18:48
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The above answers are correct in that there are better screw head types to use. Pozidriv seems really common here in the UK and they do seem to be significantly less prone to destroying both the bit and the screws.

I would also recommend though that the quality of the bit makes a difference. The best ones I've found for Pozidriv bits are Wera gold

They do also make a Phillips head version of these bits. I'm not sure if this particular make will be available in other countries but there should be some kind of equivalent. Sometimes if you pay twice as much for the bit, it'll last 5 times longer, so try a few different makes 'til you find one that holds up better.

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    Avoid using positional references for other answers. Above means different things depending on how it is sorted. Use the share link under questions and link to them exclusively. Or just use the general "other answers" – Matt Dec 21 '15 at 20:06
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Others have alluded to this, but I'm making it obvious. Are you using posidrive screws with a plain philips bit? This is a combination that will cam out easier.

Try holding the bit and a sample screw, fit them together like you're going to drive the screw. There should be a good firm fitting between the two. Any slop or tolerance that you can feel is too much so try another screwdriver bit.

Answer Try a posidrive bit with your existing posidrive screws.

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Try using Robertson square headed screws. They are less prone to this type of problem particularly with impact drivers.

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Are you sure you have a Phillips screw and not a Pozi? Using Phillips bits in a Pozi screw renders, in my experince, the result you have.

Another thing to think of: Apply pressure! With the first slip you have either dented the screw or the bit. Lean into the screw and keep perpendicular. I have never experienced I have applied too much pressure.

Second: Get the proper bit. Don't look at the screw head or carton and be satisfied it is a Ph2 but put a bit in and wiggle. It should not wiggle. At all. A good bit/screw fit is when they stick together - you should be able to lift one with the other. In my experience also screws with a good brand name doesn't always fit best what the carton says.
As much as I dislike Phillips I have a bunch of (cheap) spares to test with. Some times they have saved the day.

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You can get hardened phillips head drivers, but then you risk damaging the screw rather than the bit when you cam out.

The real problem is that the drive type isn't well matched to the amount of force you are facing in your project.

  • If you really do need to screw things this tightly, you need to choose a screw drive method, such as posidrive, torx, or similar, which can handle the torque you are applying.

  • If you can change your project parameters to require less force you can still use phillips.

  • If you must have phillips and must maintain this high torque situation, you can buy hardened bits and hardened screws which will both stand up to the force you are applying.

As you haven't given enough detail we can't advise which path to take, but know that you can resolve the situation.

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Try these Makita bits they fit more precisely so less cam-outs. I use these and love them

protected by bowlturner Dec 21 '15 at 20:41

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