Coarse Thread Screws

[Qapla]

When fastening a lose board to another one, it is usually better to use a coarse thread screw instead of a fine thread screw. The coarse thread will pull itself into the wood and grip better than a fine thread one. The fine threads tend to strip the wood as the screw is tightened - thus leaving it with less of a bite.

 

Also, a torx head screw will grip the driver better than a square head and a square one will grip better than a phillips and a phillips grips better than a straight slot.

 

That said, many screws are only available in one type of head ... if you are going to drive it with some sort of electric/battery driver and type other than a straight slot will get the job done.

 

 

 

[Tortuga]

Good point. It is also important to use the right grade of screw too, not all screws are equal. 

It may be tempting to use the box of drywall screws that you have in the shop to screw something heavy but the drywall screw heads can snap off easily and be unsafe.

Use the right screw for the job.

[Dave]

I never heard of a torx head screw before. What is that? I’m guessing it’s a five sided bit/slot. Is that right?

I find I need to keep a good selection of screws handy. Often times when I get a door- or window-latch kit where the screws are supplied, the screws are rubbish, as if made out of plastic or some kind of very soft metal causing the Phillips slot to strip out or the head sheers clean off before it’s fully screwed in.

Its hard to find anything of quality these days.

Edited April 28, 2019 by Dave

[Tortuga]

There is also a security torx that has a pin in the middle of the lead so you cant use an Allen wrench or screwdriver on them. 

I just helped install bathroom partitions at a KH remodel and all of the screws were T27 Security. 

Edited April 29, 2019 by Tortuga

[Qapla]

 

The screw type Richard was talking about is under the "Hexalobular" portion of the chart.

Edited April 29, 2019 by Qapla

[Tortuga]

Nice chart...

[Qapla]

There are also "combination" head screws.

 

Some of the common ones are Hex-head (external polygon) that also have a Slot or Phillips drive built into the hex head.

 

Another one is Robertson-Phillips hybrid

 

 

A standard T27 Torx screw looks like this

 

The T27 Torx Security like @Tortuga mentioned looks like this

 

You can see the security pin in the center of the Torx drive that prevents a regular driver to fit.

 

This is a standard Torx driver bit in some different drive styles ... as you can see, the end of the bit is smooth and solid

 

The Torx Security driver has a hole in the center to accept the pin

 

While you can use a security driver for both, standard and security heads, you cannot use the standard driver on a security head.

 

I have sets of both types

Edited April 29, 2019 by Qapla

[Dave]

Wow, I had no idea there were so many different kinds. That's very interesting, although rather complicated.

[Pabo]

Always remember - If you don't use the right screwdriver on the right screw head, you'll be screwed either way.