I’m doing some renovating of a manufactured house and need to remove/back out a lot of these screws…
… and can’t find a screw tip. Tried local HD, etc with no luck. Anyone?
That’s a clutch head screw. Try a local mobile home parts store or a Harbor Freight (where it’ll be one of a big set of bits). Clutch Head Screw Bits
I love the dope; five minutes to a solution.
Brilliant! Thank you.
And I thought I was an expert on screw heads. That’s some obscure fastener trivia, there.
You’re welcome. Back in the ‘80s, I lived in a 10’ x 60’ 2 bed trailer for 9 years. It still had the tongue on the front and painted-over tail lights on the back. It was held together with clutch head screws.
I guess those screws never made it to Europe, never have seen such a screw head. It also looks not very effective for transmitting torque.
Yeah, I searched around a bit before asking here.
And they are pretty impervious to hacking. I tried to file down a flathead to get one out with no success. What I don’t understand is why even bother inventing something like that. These things are holding up a furrdown. It’s not like they are securing some important thing.
I think it was just one of the many invented to avoid the problems of slot and philips: that in production it is difficult to keep the tool ingaged. In the competition of life, this one lost out. It doesn’t look like it’s any worse that square, triangular, hex, or torx: the tool is harder to make than a square, but also harder to damage.
Yup. We used to own a mobile home park. They used those on mobile homes a lot. Actually a good head. Can’t strip them out.
The Philips screw was intentionally designed to “cam out” when fully seated, to allow semi-automated production on assembly lines. They then came up with ACR Philips to try to eliminate this design ‘feature’. The problem with Philips is that maximum torque is applied by the driver to the fastener at exactly the spot where there is the least metal contact.
And then there is the JIS (the screw head looks like a Philips but has a small dimple in one of the quadrants). They have a different angle on the bevel and have been jokingly referred to as “Japanese Incompatible Screw” and are quite common on electronics.
The worst fastener abomination has to be the one found on modern North American wiring devices (light switches, outlets, etc.). It started out being a simple slotted head. Later Philips was superimposed over that (for the electrician who was too lazy to flip the bit in his electrician’s screwdriver?) Some time in the last decade or so, someone had the bright idea to add square drive to that. I joke that they should just machine a nicely tapered cone as it will be faster to manufacture and won’t be any more annoying to customers as the current abomination.
I think that’s the purpose – to avoid over tightening.
It’s a fair sight better than Phillips. But then again, so is just about everything else.
Thanks again to CJ, I managed to secure a clutch bit and complete my project. I called a few hardware stores (including Harbor Freight) before I found a local independent that had them. I spoke with them on the phone in the evening and was assured they had them. The next morning I dashed over. When I asked for a clutch head bit. The two employees looked at me like I was from Mars. Told them my story and they explained the guy who worked there last night was off today. After an exhausting search I finally found them. The older employee twirled it in his hands and said, “ I’ve worked here for 9 years and have never heard of or seen them”.
I can tell you from experience that’s not technically true. 
I guess they never made it to Texas either, 'cause I’ve never seen one.
Actually after reading this thread I’m sure Texas has more than its share, since we have more than our share of mobile (trailer) homes.
I thought I knew screw heads pretty well. The ones I know:
Flat
Phillips
Pozidriv
Allen
Robertson
Torx
Then there are those I’ve seen on bathroom stalls, that look like a Torx but have a big “punt” in the middle of the indentation, I presume to keep bored people who happen to have a Torx with them, from taking it apart.
Tamper-resistant Torx, yes.
Also called “Security Torx” (though tamper-resistant is a much better descriptor). I was taught to call the bits for these screws “security bits”.
I think Torx screws are my favorite. Very easy to work with and you can put a lot of torque in them. Much less likely to strip than Phillips and you’re not slipping the screwdriver out of them constantly like a flathead. In a perfect world they’d be the standard head. My WAG is that they’re too expensive to be common (due to patents, manufacturing difficulties, or a combination).
One big problem with Torx: you can engage a Torx head and turn it with a driver that’s one size too small. The small driver then easily strips the head. You can often still get the fastener out with the right-sized driver, but still, this is annoying. It matters more in a production/assembly environment than it does for the home mechanic, of course.
Fastener heads are always a compromise—none is perfect. I like conventional hex heads between 4-10 mm and Torx for anything smaller, but cogent arguments can be made for other driver shapes.
The sociocultural aspects of fastener heads are kind of interesting too. To me, slotted fasteners can seem crude, while cross-head fasteners (including Philips) seem more finished. But a socket-head cap screw (a fastener with a pocket to accept a hex driver) seem a lot more finished still, whether “pure” SHCS or the flat-head (countersunk) variant.
I know others who strongly prefer Philips-head screws because they own screwdrivers but not hex wrenches. This drives me nuts, but I care about this stuff way more than the average person. I’m aware that I’m a freak in this respect.
Now that you mention it, I think I have done this before with a powered screwdriver. 
Huh. That’s a surprise. Back in the day all of the aluminum siding that went on mobile homes where 1/4 drives. Those where good as well. I liked the clutch drive, provided you had the tool to drive them. Now, about, 45 years later, I’ve run out of my supply of both 1/4 drives and clutch drives. Of course the tools to drive them have improved vastly.