I have a screw that is 1 1/2" long, and it has two different threads around it. It's a button head, made for a Phillips-head screwdriver.
What do you call this kind of screw and its threading so I can search to find more of this kind of screw?
2
-
Hello, and welcome to Home Improvement. Interesting question; let's see if you get a good answer.– Daniel GriscomCommented Apr 27, 2019 at 19:18
-
Is it double helical, or simply machined so that every other rotation is smaller?– Wayfaring StrangerCommented Apr 27, 2019 at 20:26
Add a comment
|
1 Answer
That type of threading is called hi-lo, or sometimes high-low.
From MutualScrew.com:
High-low screws -- or hi lo screws, as they are often called -- have double-lead threads (where two grooves have been cut around the shaft). This kind of screw includes a high thread and a low thread. The unique qualities of hi-lo thread specifications help minimize the amount of material displaced as the screw is driven into the material, while also serving to create a stronger grip than would otherwise be possible.
