Bolts vs. screws
This is my first furniture piece, and I need some advice.
I am building for my daughter a desk/loft bed. I am using primarily 2x4 and 2x6 lumber. The legs will be 2x6 as is the mattress box. I am using lap joints for a nice look. However, this is where I am second guessing. The box that the mattress will be laid in is 2x6 with a plywood bottom. Since 2" thick lumbar actually measure 1 1/2" , using a lap joint makes the individual boards a rather thin 3/4". I had thought to use carriage bolt (1) on each corner through this joint (the mattress box is rather heavy as-is, without mattress and kid). The problem I see is that at only 3/4" thick I can't countersink the nut and retain any real strength in the wood. The nut obviously can't be INSIDE the box as it would be against the mattress. i had also planned on a couple wood screws (screwed from the inside) just to give the corners added strength.
I guess I am wondering if I am really underestimating the strength of woodscrews? meaning, could I use just 3 or 4 wood screws (per joint) and have sufficient strength?