fencerailingwood
I have a 2×4 wood rail between two 4×4 wood columns. It looks something like the drawing below:
The 2×4 rail is warping a little bit, so I want to attach a 2×4 under it so that it can straighten the rail. But I don't want to use screws that will be seen from the top of the rail.
What can I do to securely attach a 2×4 under the 2×4 rail without having to drill at the top of the rail? Or is there a better way to straighten the 2×4 rail?
I'd face-nail with a brad gun. 3-4 nails. Fast, easy, and likely stronger than the rear-facing screws.
As a PS note that you will likely want to have diagonal brace on that frame to prevent racking as you remove the gate from the hinges.
Option 1: Don't use screws. Old-school cabinet makers used dowels and glue. It's not difficult, but you'll want to read up on alignment techniques. Joints are very strong.
Option 2: Use pocket screws. They're what modern cabinet makers use. They're probably cost- and effort-prohibitive in your case, though, since they require special tools (or advanced technique) and your work space is very tight.
Option 3: Use long screws from the bottom. If your dimensions are correct, and your top panel really is 2 inches thick, you have enough material to counterbore from below and run the screws in that way.
Best Answer
You could screw up through the lower 2x4 into the top 2x4, such that the screw heads would be on the bottom of the lower board and not seen from the top.
But I think there's a different question here: Why reinforce the existing board?
When working on problems like this, I first try to determine the root cause of the problem. Did that 2x4 warp because a 2x4 is not sufficient for that purpose? Or did it warp because the original board was poorly selected (it had a big knot, or gnarly grain).
If a 2x4 is indeed sufficient, then why not just replace the original board, instead of trying to "correct" it with a reinforcement?
If a 2x4 is not sufficient, then how about replacing with a correctly-sized piece of lumber instead of reinforcing the existing board?
In other words, reinforcing the existing board would be low on my list of choices.