How to Drill a Shank Hole or Clearance Hole
Home improvement expert Ron Hazelton shares his tips on how to securely screw two boards together by first drilling a clearance hole. For more woodworking videos and tips, visit http://www.ronhazelton.com.
Transcript:
Screws like these, which were originally developed for drywall and wallboard, have become increasingly popular for woodworking projects, partly because they can often be put into materials like this soft pine, without even drilling a pilot hole. But you should be aware of one thing, even though these screws can tighten up on the head like this, they may not pull to pieces of wood tightly together. As you can see right here I've got this tight, but here's still a big gap in between. The reason is that these screws have threads all the way up to the head. So in this case, it's tightening into this piece of wood before it's tightening into this one.
The solution is to drill what I call a clearance hole. Now a clearance hole should be large enough to allow the screw to drop through without the threads having any effect. This way when you tighten into a second board you can be absolutely certain that when the screw is tight here, it's also tight here.
Not convinced.
Well, let me show you my dollar bill test. Here are two pieces of wood, that same screw, no pilot hole. I'm going to tighten this down, the screw is tight, now let's see about the dollar bill .... slips out!.
Now over here we've got our clearance hole. Let's do the same thing, we'll drive a screw in, make sure the head is tight and give a tug on the dollar bill and that's not going anywhere.
So the next time you want to use one of these kind of screws, remember those two words; “clearance hole”.
Thanks for watching!
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