Favorite construction screw head design

[nadogail]

The screws used to attach the skin on a lot of enclosed trailers have a very unique head. It looks like Torx, but it is not Torx. It is an eight sided opening. They actually use a #2 square drive bit. I assume the design is so workers on the assembly line don't have to be as accurate on lining up the bit to install the screw.

Are they Clutch Head screws?

 

[Shiftless]

What happened to hex heads?

Hard to flush mount or recess a hex.

They are used for lags and ledger screws, but even many of those are being replaced with flat heads that look more like a pan head, so they retain strength at the surface

I like hex head sheet metal screws with a magnetic bit in my impact driver. Great for mounting steel electrical boxes and similar tasks. For decking I use torx. Cabinetry is Phillips. Structural stuff is GRK.

 

[Farmall450]

Torx, no question. It's the default for high quality screws like grk and spax

Yup. I also like that the boxes I get always include an extra bit if you don't want to go looking for a T25.

 

[Mfaz28]

Torx followed closely by Robertson. Phillips suffers from cam-out.

 

[mike93lx]

Torx followed closely by Robertson. Phillips suffers from cam-out.

I wouldnt say Philips suffers from cam out. It's designed to cam out, but people don't treat it like that

 

[Wiz02]

Torx may objectively be a better design, but a #2 Philips screwdriver or bit is so much more convenient for me than Torx. For me, the convenience outweighs the marginal potential increased torque that can be obtained.

 

[Mfaz28]

“wouldnt say Philips suffers from cam out. It's designed to cam out " ???? It cams-out. Not good. No accurate torque available. No positive engagement. Drywall screws only.

 

[mike93lx]

“wouldnt say Philips suffers from cam out. It's designed to cam out " ???? It cams-out. Not good. No accurate torque available. No positive engagement. Drywall screws only.

That's its purpose. The fact that's its improperly used isn't the fault of the drive type

 

[mwalsh9152]

I prefer torx. They never wear out on me, and I use them A LOT. Like hundreds per day, 2-3 days a week. I hate the Robertson. Use them on pocket holes, and those definitely wear out often.

 

[cannuck]

I may lose my Canadian citizenship for posting this, but; I prefer torx over Robertson by far (for recessed head fasteners). However, when the nut and bolt are above surface I vastly prefer reduced head, 12 point male fasteners so that they can be turned or held by sockets and/or flat wrenches with 30 degree range of motion. Using torx in expposed fasteners IMHO just reduces their accessibility.

 

[Ton ton]

A proper "Genuine Robertson" screw with a Genuine Robertson driver is awesome. It will lock onto the driver and not fall off. Not that "square drive" BS.

GRK is my choice for anything over a #10 or longer screws. Fun fact, GRK was also a Canadian company like Robbie before being swallowed up by ITW. I guess we Canadians are great at screwing.

You said it. Not me. But I like the last sentence.

 

[Mfaz28]

Phillips cam-out discussion; “There has long been a popular belief that this was a deliberate feature of the design, to assemble aluminium aircraft without overtightening the fasteners.[14]: 85 [15] Extensive evidence is lacking for this specific narrative, and the feature is not mentioned in the original patents.” Although later specifications mention it. It’s most likely a distraction based on a design weakness. Therefore, the original design did not include a cam-out feature. It was an unintended circumstance that an attempt was made to explain.

 

[mike93lx]

Phillips cam-out discussion; “There has long been a popular belief that this was a deliberate feature of the design, to assemble aluminium aircraft without overtightening the fasteners.[14]: 85 [15] Extensive evidence is lacking for this specific narrative, and the feature is not mentioned in the original patents.” Although later specifications mention it. It’s most likely a distraction based on a design weakness.

The last sentence that you omitted:

However, a 1949 refinement to the original design described in US Patent #2,474,994[17][18][19] describes this feature.

None of us will ever know the original intent, but cam out is a factor of Philips and should be considered when choosing it for a drive type

 

[Mfaz28]

“Although later specifications mention it”

 

[mike93lx]

“Although later specifications mention it”

Seems odd to call out the patent once and then change it to different terminology

Either way, there are enough drive types that we can each have our own favorites and opinions, and we are sure to never have to agree

 

[Mfaz28]

Not odd at all. There was clearly an unintended effect to the design. Instead of expensive re-engineering. Just add it to the description. Seen it many times in my 43 year profession as a mold/die maker.