I was going to make a joke about old dogs learning new trucks, but that would be too corny.
My old dog can't jump up in the back of this pickup so I made him a set of steps.
I used left-over material from another project, using about a half sheet of plywood. If I hadn't had the material on hand, I would have made the steps 12-inches wide (instead of sixteen), and I think this could be made from a single 24- by 48-inch piece of 3/4-inch plywood.
Tools and Materials:
One-half sheet of 3/4-inch plywood (I used Baltic birch, which is pricey, but any plywood would do with the right finish).
Square -- I also used a speed square, but you can get by with a carpenter's square.
Pocket hole jig
About 50 1 1/4- inch stainless steel pocket hole screws (if you're using hardwood, like Baltic birch, get the fine thread screws).
Orbital sander and sandpaper (various grits).
Outdoor urethane sealer and brushes.
2-Foot length of carpet runner (cut in quarters to cover the four steps).
Heavy duty stapler and mallet
2-Foot long piece of "Dual Lock" fastener material (It works like velcro, but instead of hooks and loops it just has only one side. Two pieces of this material will lock to each other. Velcro would probably work, but I had this so I'm using it.)
Note: I put this project together using a pocket hole jig. I'm not shilling for the manufacturer, I just think they are a quick and easy way to knock a project together. Because I also plan on using the steps myself, I decided to add cleats under each step, which sort of makes the pocket hole jig superfluous. I do think these make really strong joints, and the cleats under the steps may not have been necessary, I just didn't want to take a chance. The upshot is that you don't really need to use a pocket hole jig at all, you can just screw on the cleats and screw the steps to the cleats.
Step 1: Mark and Cut the Plywood
Cut two, 6-inch wide by 48-inch long pieces for the sides, and four 7 1/2-inch by 16-inch steps. Also, cut a couple of 4-inch by 16-inch braces, and three sets of 1-inch by 6 1/2-inch "cleats" to add support under the steps. If you started with a good, square 16-inch wide strip of plywood, you can cut all the steps and brace pieces from that strip and all will fit flush between the side pieces. It's not important that steps and braces be any particular length, but they must all be the same length. I cut the steps from various pieces leftover from another project, and it was really hard to get perfectly square cuts on the short pieces using a circular saw. Tiny variations in squareness and length made it impossible to get the final frame perfectly square. If I decide I can't live with the skewness, I may just add a few more strips of carpet where the steps rest on the tailgate.
In retrospect, I wish I had just used a fresh piece of wood. I don't like using the heavy circular saw, but that's what I have so I take my time and try to make the setups, as square as possible, clamping a jig next to the line to get a straight cut. Just be sure you're cutting on the right side of the line for your measurements. Also, to keep the wood from splintering, don't set the depth of the cut too deep. The jig I'm using in the pictures is one I made after watching the guys on "This Old House" make one. I'm sure there are instructables here describing how to make a jig like this for your circular saw.
Once you have the parts cut, lay out where your steps will be attached. I made each step 8-inches high, including the 3/4-inch board for the step. One of the pictures shows how I used a carpenter's square with a speed square to measure up 8-inches from the back of each step to the front of the next step. Lay out the four steps, drawing lines for the top and bottom of each tread. Trim the ends of the side pieces to make a notch where the steps will rest on the tailgate.
I made the top part, where the steps lean against the tailgate, 1 3/4-inches wide to allow for the step, plus the 1-inch cleat. I think this will be plenty of material to support the weight of the dog or a person (okay, I'll admit that I'm also planning to use these steps to get in and out of the pickup). You can round the ends or make straight cuts, as suits you. Remember, though, if you trim any wood from the lower corner, where the steps meet the ground, you will be changing the height and angle of your steps. My tailgate is 33-inches off the ground; I measured 33-inches outward, from a spot directly below the edge of the tailgate to make a 45-degree angle. It happens that this was pretty close to 48-inches (with the added thickness for the top step). If your tailgate is at a different height, you will need to change the length or angle of the steps.
A good check at this point is to park on level ground and lean a cut-out side piece against the tailgate. Use a level to find out the angle your steps need to be at, relative to the side piece, to be level. Draw a line. Make that your angle for all the steps.
Step 2: Drill Pocket Holes
I bought a pocket hole jig a while back, and it seems like every project provides an opportunity to use this simple setup. As discussed earlier, you could make this project by just mounting the cleats and attaching the steps to the cleats, but I've got this setup so I'm using it. The pocket hole jig makes a strong joint, but I don't trust it to support my weight on these steps. The cleats add sufficient support to make me feel secure.
I drilled three pocket holes on the underside of each end of each step. Similarly, the brace pieces, that will be attached inside the lower edge of the side pieces, get a couple of holes at each end. I'm also using the pocket hole bit to drill recessed holes about a quarter-inch deep near the ends of the cleats.
It's best to drill the holes before sanding the boards, as the drill leaves a few burrs.
Step 3: Sanding and Painting
I don't like sanding, and I don't like painting, so I won't spend much time discussing this step. I will say that I highly recommend buying a really good quality dust mask that you can actually breathe through. Don't even bother with those little paper cup/elastic band things, they don't work a bit. I have done a lot of sanding without good breathing protection, and I really wish I had learned that sanding doesn't have to be miserable. I'm not bothering with the brand here, but get a mask that fits comfortably over your nose and chin. Adjust the thing correctly and it will make the job of sanding much more safe and less miserable.
Clamp the two side pieces together and sand the edges so they all match up nicely. Unclamp the pieces and continue sanding the sides and each of the steps. Most of the step is going to be covered with carpet, but get the edges where the carpet doesn't cover.
I sanded everything with 80-grit paper, then went over the side pieces with 40-grit, and something finer that I don't remember. They came out nice and smooth. I didn't sand the step pieces very much, as they will be covered with carpet.
When you're done sanding, wipe the parts down with a cloth. I put some mineral spirits on my cloth because that's what an old carpenter told me to do.
I put one coat of outdoor urethane on each side, being careful to get all the edges. Let it dry overnight ad hit everything lightly with 120-grit sandpaper, once the dew has lifted. Wipe everything down again, and apply another coat of urethane. That's all the painting I'm doing.
Step 4: Add Carpet to the Treads
Here's where the heavy-duty stapler and mallet come in. Position one of the four pieces of carpet so that the edge overlaps the underside of one of the steps. Staple the carpet in place near the middle, and then work your way toward each edge, trying to make a more or less neat line of staples. You can just whack away with the stapler, which is satisfying and effective, or you can position the stapler and whack it with a mallet, or a log or what have you.
Wrap the carpet around the step, and pull it snug around to the underside of the step. Staple the middle and work your way toward each end. You don't need a million staples, just make it secure. Trim off a strip of carpet to use later on the underside of the notch that rests on the tailgate. Repeat for the other three steps.
Step 5: Screw Everything Together
Lay one side piece on its side (hopefully you can still see the marks you laid out in Step-2), and line up the first step with the marks. Be sure you are using the angle you got in Step-2. Line up a step to the marks, and use a square to keep the step vertical while you screw it in place. Make sure the step board and carpet don't hang out past the back edge of the side piece. This will be important when we anchor the steps in place later. Repeat this for all the steps on one side, being sure the steps are snug to the side pieces.
Lay out the second side piece and flip the other side piece (with the treads) over, so the two sides line up. Measure the distance from the base of corner of the side piece to the corner of the first step. Use this distance and a square to line up the other side piece and screw the treads in place. Make sure you maintain the 8-inch spacing between the steps. Once the steps are secure, flip the thing over so the underside is facing up, and mount the two braces (one near the top and one near the bottom), being sure that the steps are square before mounting the braces. These braces are intended to keep the stairs square, so pay attention to this. I used clamps to hold the two sides together. Make sure that the parts are snug together when tightening up the screws. If a gap forms, back the screw out and try again, use a clamp if necessary.
I had strips of carpet left over, so I used contact cement to glue a couple of pieces to the underside of the notch that rests on the tailgate. Since these often get used on uneven ground, I glued the carpet strips to the notches with the rubber side facing outward to keep the steps from sliding around. I also added a couple of strips of carpet where the steps sit on the ground, and secured these with staples.
Step 6: Secure the Steps to the Tailgate
To keep the steps from sliding around in the back of the pickup I'm securing them against the tailgate by attaching a door sweep to one of the side pieces, making it flat against the side piece with the rubber part extending outward from the edge. This "flange" will be pinched in the tailgate hinge when the gate is closed. A strip of carpet would probably work just as well.
Put the steps on their side, just inside the bed of the truck, with the flange on the bottom edge facing outward. Slowly close the tailgate, snugging the top edge of the steps up against the tailgate and catching the flange in the gap between the tailgate and the bed. When the tailgate is fully closed, the steps should be snug up against the tailgate. Make two marks, six inches apart, near one end of the steps, with matching marks on the tailgate. Make another set of marks at the other end of the steps and tailgate. The upper edge of the steps will be secured (hopefully) with the "Dual-Lock" material. Open the tailgate and clean the area between the marks with alcohol. Apply the Dual-Lock material to the tailgate and the steps. That should be adequate to secure the steps, when driving. This vehicle also has a lock on the tailgate, so the steps will be locked in place. A determined thief could still remove these, but the steps would probably be damaged in the process.
I'm not sure how this setup will perform over time, particularly in hot weather. I haven't gone on a long drive or bumpy roads with them yet, so time will tell. I expect that bungee cord will come into play at some point.
I'll be honest, my dog mostly just bounds into the back from the first or second step, not even touching the other steps. He uses more of the steps going down, but one big step (or a box) probably would have suited him just fine. On the other hand, these steps make it much easier for me to load stuff in the back, and they don't really take up that much room.