I'm building a small wooden foundation for a new shed (pic below, joints in question highlighted). I'll be using wood screws to put it all together. My question is simple, should I be screwing through the perpendicular piece into the butt of the other piece ( =|| <##)? Or try to toenail the screw from the butt piece into the cross piece ( ##> =|| but a toenail angle)?
My experience is that if you use a pre-drilled hole that includes a countersink using a tapered drill bit like this:
...that it can be very easy to use 2 1/2" or 3" length deck type screws in either toe screw application or thru to end grain joining. If toe screwing is done properly with three screws it is ultimately stronger then screwing into the end grain of the wood at the butt joint. It does take some extra care to make sure that when tow screwing that you keep the member aligned with your layout marks. Often times I have found it useful to pre-drill all three pilot holes (two from one side and one on the other) and then start all the screws together. This way there will be less tendency for one of the angled screws to try to pull the piece off the line.
When using screw construction like this I prefer to use stainless steel screws with a square drive bit. Large screws with a Torx drive are also OK but can strip easier than a square drive in my opinion and experience. I also keep two power tools handy at the work site, one with the pilot drill and the other with the screw driver bit. I also prefer the screw driver tool to be a unit specifically designed for driving screws as they generally have lower RPM (more gear reduction) and thus more driving torque even at low speed selected on the variable speed trigger.