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I know that pre-drilling before screwing has many advantages but am wondering if pre-drilling is also useful for nailing. Pre-drilling for nailing seems to make sense because nailing also causes wood splitting. But, it may be disadvantageous because it may reduce the power to grip the nails, making them loose.

Should I pre-drill before nailing or not?

  • I don't know the answer to this but adding something of my own: I wonder if the answer is different for nails with smooth vs ridged shanks (e.g. finishing nails vs ring nails)? – Jason C Dec 17 '15 at 2:48
  • Depends how big the nail is as well. A nails strength is related to the pressure is creates. The effectiveness of said nail would have varying needs depending on the project. I think this is really dependent on what nails you are using and what you are building. – Matt Dec 17 '15 at 4:33
  • Soft wood doesn't tend to split with "normal" nail sizes and "normal" nail to wood piece ratios, and you don't normally use nails with hardwood, so... but when you're in doubt, sure pre-drilling is better than splitting. – Damon Dec 17 '15 at 10:13
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Should I pre-drill before nailing or not?

Unfortunately the answer to this is, it depends.

With certain woods, particularly when nailing near the ends of boards, pre-drilling can be advisable. A different fix when nailing near the end of a board is to leave the board over-long (where possible) and then cut to length after the nails have been driven home. This is often done on decking boards.

When nailing along the length of a board another way to lessen the tendency towards splitting is to stagger nail positions so that you're not driving the nails in aligned with the grain:

Staggered v. unstaggered nailing

In case you're unaware, the type of nail matters here. Nails with blunt tips, perhaps counter-intuitively, split wood less than sharp nails because they crush wood fibres as they go in rather than parting the wood ahead of them (working like a wedge). And oval nails are better than round nails as long as the long axis is oriented correctly, in line with the grain.

Where the nails you're using are sharp and you'd like to take advantage of the effect of a blunt tip a very old tip is to put the head of the nail on a hard surface and tap the tip with the hammer to blunt it, but it's very easy with soft wire nails for this blunting blow to bend the nail slightly. So it's much more reliable to snip the tip off the nail with side snips or pliers. Nails are commonly only mild steel wire and even with a beefy nail this isn't too difficult to do.

But, it may be disadvantageous because it may reduce the power to grip the nails, making them loose.

If the hole is drilled full size that will occur. The drilled hole should be undersized, roughly 75% of the diameter of the nail.

  • It might be a good idea to discuss cut nails or forged nails, which have a rectangular cross-section and don't tend to split the wood as much (if driven correctly). – grfrazee Dec 17 '15 at 13:46
  • @grfrazee, given my complete lack of experience with them :-) and their relative rarity these days I think I'd prefer not to try to figure out how they factor into all of this. – Graphus Dec 18 '15 at 12:17
  • Fair enough :) they've been making a bit of a comeback in the hand woodworking crowd. – grfrazee Dec 18 '15 at 12:47
  • Doing some unrelated research, I came across an interesting citation from this paper: "Scholten found that the highest nail withdrawal resistance values were obtained from sharp tip nails on wood with low density. Wood with high density did not divide after nailing. He proposed common nails for wood with high division resistances." Academically, I'd love to see a study of pre-drill diameter:nail diameter ratios vs pull-out strength changes in various woods. I don't have the measurement equipment to do it myself. – Jason C Mar 9 '16 at 1:35
  • @JasonC, re. pilot hole diameter and resistance to pull-out, a rough-and-dirty test might give enough info to be worth the effort, similar to how some adhesive tests are done. I'd propose nailing two pieces together in line, one end overlapping the other. Clamp one board to the bench very securely, then hang successive amounts of weight off the second until the nails pull free. – Graphus Mar 9 '16 at 12:22
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If there is a danger of the nail splitting the work piece, PRE-DRILL. Otherwise nail away..

  • How far do you predrill? – johnny Jul 7 '17 at 18:22

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