I recommend using 1/4 inch carriage bolts to mount the hinges and latch because they can not be backed out like screws can.
Plus they hold much firmer and will help reduce future door sagging problems.
Router bit: You’ll need a straight 1/4 inch router bit available from any hardware store.
Router collar: You’ll also need a router collar with an inside diameter slightly larger than 1/4 inch.
It will consist of the collar and a threaded ring to hold it to the router base.
You can typically purchase them individually or in a set.
Adjust the cut depth: Adjust the cut depth of the bit to the thickness of the siding plus the thickness of the trim, plus about 1/8 inch extra.
If you are using typical 7/16 inch siding that will add up to 1 inch.
See Figure 7, First router cut: The gap between the inner and outer door trim will guide the router collar as the bit cuts through the siding.
Start at the bottom of the side where you are installing the hinges and pull the router through the gap between the trim up to the top and about half way across the top of the door.
Make sure you cut well past where the hinge will be mounted so that it will not interfere with the router base when you start the second cut.
If you are not cutting through the siding then set the cut depth a little deeper until you just graze the 2×4 frame below the siding.
If your depth is set a little too deep it will not hurt anything. You will just have to work harder because you are cutting through more wood.
Mount the hinges: Locate where you want the hinges and drill ¼ inch holes for carriage bolts.
Use a long drill bit because you will have to go through 1 inch of trim and 3 ½ inches of wood.
Mount the hinges by driving 5 inch carriage bolts into the holes.
Place a second ladder inside the shed and climb inside. Install the washers and nuts and remove the door spacers.
Second cut: Finish cutting across the top of the door where you left off and cut and down the latch side to the bottom edge.
Open the door: Open the door and inspect your work.
If you located your cut lines correctly you will have an even half inch reveal all around the door.
Mount the latch: Locate where you want the latch to go and drill ¼ inch holes. Mount with carriage bolts.
Remove bottom plate: And finally, use a hand saw to cut the bottom plate out of the door opening between the door frames.
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