self tapping screws

[Strathead]

A tap is designed to remove metal, not just displace it.

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A green, but that doesn't mean that a self drilling screw that drills a hole and then displaces metal like the link Kwired included and complies with the two threads of engagement are not acceptable they are.

"Sheet metal screw" and more specifically "machine type screw" are not defined terms. That is still an issue with the code book. I have run across many people who call self drillers that comply with the code, sheet metal screws. The key here is "2 threads of engagement" and it can be called a lawn mower screw for all I care.

 

[kwired]

A green, but that doesn't mean that a self drilling screw that drills a hole and then displaces metal like the link Kwired included and complies with the two threads of engagement are not acceptable they are.

"Sheet metal screw" and more specifically "machine type screw" are not defined terms. That is still an issue with the code book. I have run across many people who call self drillers that comply with the code, sheet metal screws. The key here is "2 threads of engagement" and it can be called a lawn mower screw for all I care.

First you had me thinking what the heck you were trying to say with "A green", then I realized voice recognition picked that up when you meant "agree".

The screws in my link likely cut the threads instead of displacing metal.

 

[tom baker]

We should step back, what is 250.8 trying to accomplish? Its a prescriptive rule (how you do it) to comply with the performance rules (what we are trying to accomplish) in 250.4(A)(5). as explained in 250.4.
Creating the effective ground fault current path is the most important part of the grounding, it saves lives.
250.8 used to say "no sheet metal screws" which meant a drywall screw could be used. For code language, its pretty clear. Engage two threads, or 10/32 in 1/16" thick metal. Or a nut and bolt.

 

[kwired]

We should step back, what is 250.8 trying to accomplish? Its a prescriptive rule (how you do it) to comply with the performance rules (what we are trying to accomplish) in 250.4(A)(5). as explained in 250.4.
Creating the effective ground fault current path is the most important part of the grounding, it saves lives.
250.8 used to say "no sheet metal screws" which meant a drywall screw could be used. For code language, its pretty clear. Engage two threads, or 10/32 in 1/16" thick metal. Or a nut and bolt.

But these days everyone wants to focus on what it says and not what it is intended to mean, even when what it says doesn't quite make sense or can be taken the wrong way.

 

[Strathead]

First you had me thinking what the heck you were trying to say with "A green", then I realized voice recognition picked that up when you meant "agree".

The screws in my link likely cut the threads instead of displacing metal.

After studying the picture I see they do. However there are some that displace, and there is nothing wrong with that as long as they engage two threads.