Thread Laps in Self Tapping Screws

On 9/16/2019 7:18 AM, Engr wrote:> Is there any standard for Thread Laps in Self Tapping Screws >

Thread "laps"?

If you mean pitch. No not really. Those for sheet metal tend to have large modestly course pitch threads. Others can be different. Trailer deck screws or others intended to mount to structural steel often have thread that looks more like a fine pitch machine thread. Drywall screws for use with metal studs have a fine pitch because it has to hold in one layer of sheet metal as opposed to pulling two pieces of sheet metal together

Very informative. Would have been worlds better with pictures.

I have antenna TV, not cable, and enough dial-up and cellular Internet access for my own mainly text reading needs but not much to spare. I won't be offended if you find and post a reference you like better.

'twasn't a swipe at you, just saying it would be great to combine their excellent textual descriptions with some line drawings.

Also, you can thank me for having trimmed the post to a reasonable size ;).

Text OK, but the video wasn't just bad, it was misleading. The vid showed more screw heads than points. Ridiculously lousy vid. Boo on the hardware-ignorant secretary who made it up for them.

better. A line of text description and small pic that even Dialup Jim(tm) could download! ;) One for each type. This is the one I used to find the best deck screws (type 17) years ago.

Not sure I'd agree about drive pins, called U drive, being permanent, they're easily removed with the right tool like a small cold chisel with a gap to go around the shank. They're often used for engine number plates on some older British engines and get removed when the block is decked.

I collected worn and chipped diagonal cutters at work for that sort of task. They grab round heads and broken-off stubs better than Vise-Grips.

They make really good nail pullers too. Mostly to get the head started out of the wood. Then a good pry bar can finish with minimal damage done to the wood. I have maybe a 7 inch pair with a slightly offset head that works really well. Better than most of my specialized nail pullers...

The small angled flush-cutting "dikes" used in electronics work best as pin pullers, but not afterwards as flush cutters. Steel damages their knife-like edges.

Yeah, those small, precession jobbers don't take much abuse. I've pushed them a tiny bit too hard a few times. Tedious as all get out but you can usually resharpen, fix them once or twice before giving up on them...

I reground one and decided it wasn't worth the trouble, since locally made Xuron stamped dikes cost $4 at the time, and worked as well as the forged ones.

The ones Production turned in for replacement had either opened at the tips and could be shortened, or been used to cut steel and nicked, usually close to the hinge for leverage.

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Last ones (4.5 inch?) I bought were Diamalloy for around $15 each. They were pretty decent stuff back then (~20 yrs). You could actually cut a thin piece of paper all the way across their cutting edge. Most of the crap you get from a big-box either won't cut paper or will leave a gap in the cut.

I was able to successfully bend the tips back together slightly once. I had that pair in my field tools. They worked for slitting hard-line coax shield by nibbling but you run the risk of damaging the tips by spreading...