Summers a great time to be a kid. One of my favorite memories from childhood is of days spent in the local park playing on the awesome sand digging excavators. I spent hours digging sand, looking for buried treasure, (and occasionally finding cat poop), and in general having a great time. So now that I have a few nieces and nephews who are the right age, I decided that I would build a sand digger of my own so that they could find the same enjoyment from it that I found in my youth.
In this Instructable you will learn how to build a sand digger/excavator from recycled pallet wood. This is a fun and very inexpensive project costing less than 25 dollars to make. Additionally this project requires only a few tools and about a weekends worth of time investment which makes it a perfect summer build.
Step 1: Tools and Materials
Out of all the projects that I have posted to Instructables so far, this is perhaps the one where you get the most bang for your buck. In total I spent just under 25 dollars to build the sand digger and most of that was for expensive hardware from a big box home improvement store. I was able to get everything else for free or for very little cost by making use of free pallet wood and an old office chair that I picked up for 2 dollars at a garage sale. Below you will find a list of the materials I used for this project as well as information regarding what they were used for.
- 1 - 2 Pallets: you can make this entire project from one pallet if you get lucky and find a really nice one with no cracked or bowed boards, however I suggest picking up two to give yourself some wiggle room. Also, I suggest using a heat treated pallet as opposed to a chemically treated pallet for two reasons, first because you're going to be cutting it apart and the saw dust could be bad for your health, and second, because it's a kids toy and I don't think anyone would want their kids to be playing with chemically soaked wood.
- 3/4" galvanized pipe flange
- 12" length of 3/4" threaded galvanized pipe
- Three 1" L brackets
- Waterproof Wood Glue
- Cheap Office Chair: I Picked up the one I used for this project for $2 at a garage sale. the most important thing to look for is how the seat of the chair is attached to the base as you will be re-purposing this piece to make the pivot for the digger (see step 3). Additionally you'll use the back rest from the chair to make the seat of the digger.
- Assorted Lag screws and Bolts: These will vary depending on the thickness of the pallet you use to build your sand digger.
- Paint (Optional) (See step 13: Painting!)
- Cording (Optional) : for wrapping the handles of the digger, (See step 14: Finishing Touches)
- Coil Spring (Optional): To create spring assisted lift for the boom arm so that young diggers won't struggle with the weight, (See step 14: Finishing Touches).
You're not going to need a lot of tools for this project, in fact you can probably do almost everything you need with a hand drill, a circular saw, and a set of wrenches. beyond those tools I also used a band saw, some clamps for holding glued pieces, and a table saw for cutting straight edges on some of the bowed pallet deck boards.
Step 2: Disassembling the Pallet
The first step of this project is figuring out how to get the pallet apart without destroying it. If you've never ripped a pallet apart I can promise you that this is more difficult than it might sound. after about 20 minutes of trying my hardest to pry the deck boards from the stringers using 2 pry bars I had made no progress against the ridiculously strong nails that where holding everything in place. Eventually I gave up on the pry bar thing and used my circular saw to cut the through the deck boards as close as possible to the stringer boards on either side of the pallet so that I would only have to contend with the center stringer in order to free the deck boards. After making the cuts with the circular saw I was able to lever the now mostly free pallet deck boards, bending and torquing them back and forth until they came free of the center stringer.
Once all the boards were separated I turned my attention to nail removal. I knew that I'd be cutting and reassembling the boards so I wanted to make sure that absolutely all of the nails where out as it only takes one nail to ruin a perfectly good saw blade.
When everything was said and done I ended up with 13 relatively nice nice deck boards that measured roughly 30" long by 3" wide by 5/8" thick and 3 nice stringer boards that were roughly 30" long by 3" wide by 1" thick. This gave me enough raw material to build the entire digger with relatively little scrap left over. If you're planning to do this project I suggest picking up two pallets, I lucked out and was able to use most of the wood from my pallet but it is very easy to bust a few boards in the process of ripping the pallet apart or to end up with one or two boards that are cracked or bowed beyond usefulness.
Step 3: Making the Base
With the pallet completely disassembled you're ready to start the build. The easiest way to build the sand digger is from the ground up so I suggest starting with the base. To make the base you will first need to create a half lap joint in two of the stringers so that they can be combined to make a "+" shape. To make the half lap joint I used a table saw but you could also do it with a hand saw by making a series of closely spaced cuts in the middle of the stringers that go half way through the width of the stringer and then using a chisel to hog out any remaining wood.
Once the stringers are combined the next step is to created a mitered square frame using 4 of the pallet deck boards. This frame will be attached to the stringers and will work to stabilize the base. Additionally they make a nice raised floor for younger diggers to perch their feet on.
Lastly I took a 12" square of plywood and fixed it directly to the center of the base. On top of this I attached the center support from the office chair to create the female side of the center support and pivot point for the digger. Note that the office chair you find might be different from the one I used. What you're looking for here is a center support with good strong attachment points and a hollow center pipe. You'll see why the hollow center pipe is important in the next step.
Step 4: Making the Carriage (The Seat and Boom Arm Support)
With the base out of the way, the next step is to create the carriage. The carriage is just my fancy name for the component that the seat is mounted to and that the boom arm of the digger attaches to. To make the carriage I started by cutting and reassembling the middle pallet stringer to create a board that was roughly 32" long , 5" wide, and 1" thick. Next I cut this board to create two pieces, one 24" long piece and another 7" long piece. The 24" long piece became the platform where the seat was mounted and the 7" long piece was turned 90 degrees and attached to the 24" long piece to create the mounting point for the boom arm. The two parts were glued together and 2" long lag screws were screwed into place to ensure a strong connection.
The seat for the sand digger is actually the back support from the office chair. to attach it I simply used the existing mounting holes.
With the carriage built and the seat attached the next step was to mount the the 3/4" pipe flange. The flange was mounted to the underside of the carriage, roughly in the center. After the flange was installed the 3/4" pipe was screwed into it to create the male end of the pivot.
With the flange and pipe installed, I mounted the carriage to the base by sliding the 3/4" pipe from the carriage into the larger diameter pipe of the chair support attached to the base of the digger, see the picture for an example of what this looks like.
Lastly I drilled a 1/2" hole into the mounting point for the boom arm as shown in the last picture on this step. Later on the boom arm will be mounted through this hole via a 1/2" bolt and lock nut.
Step 5: Making the Boom Arm
After the carriage is finished the next piece you need to make is the boom arm. The boom arm is actually made of two separate pieces. to make the boom arm, take two of the pallet deck boards and cut them so that they are both approximately 30" long. next round the ends and then drill a 1/2" hole into both ends of each board.
Step 6: Making the Handles
The handles could be as simple as a rectangular length of wood or if you want you can embellish them with a bit of fancy cutting to make them look more mechanical. I chose to make a few simple cuts to give them a little character but essentially all you need here are two pieces of wood that are roughly 16" long and about 2" wide. Each of the handles will be mounted differently depending on whether they move the stick arm or the boom arm so for now you don't need to worry about drilling any holes.
Step 7: Attaching the Boom Arm and Handle
With the carriage, boom arm parts, and handles made you can now assemble a bit more of the digger. Start by drilling a 1/2" hole into the bottom end of one of the handles, and then follow the diagram on this step to learn how to bolt everything together. Once you have all the parts correctly attached you can tighten down the bolt and nut to hold everything in place, but don't make it too tight as the handle and boom arm need to be able to move with ease. Once everything is assembled you should have something that resembles the picture on this step.
Step 8: Making the Stick Arm
The next step is to make the stick arm. The stick arm is the arm that the bucket is mounted to and as such we need to do a bit of work to make sure that it is strong enough to support the weight of the bucket as well as the force of digging. To make the stick arm, start with one of the pallet deck boards (30" X 3"). If you choose, you can cut this board down to give it a more mechanical profile, or you can leave it as a rectangular length of wood. On to one end of the arm, attach two 3"X 3" squares of wood using glue and screws. The purpose of this is to build up the thickness of the stick arm at the end so that there is enough material to support the bucket attachement.
Step 9: Making the Bucket
Making the bucket was one of the trickiest parts of this project. Pallets don't generally come with extremely wide sections of wood, so to make the sides of the bucket I had to cut and join two of the pallet deck boards to create one board that was wide enough. Once that was done I cut the board in half to create two pieces that were 12" long and 6" wide. Next, the bottom edge of each of these boards was rounded off as shown in the picture to create the scoop of the bucket and then the boards were trimmed slightly from 12" long to about 10" long so that the bucket wouldn't be to large in size. With the sides of the bucket complete the next step was to build the top and back of the bucket. To do this I cut and glued 7" long sections of pallet deck board between the two sides as pictured. Lastly, Just for fun, I cut teeth into the bottom of the bucket to give it a slightly more realistic look.
Step 10: Combining the Stick Arm and Bucket
With the stick arm and bucket complete, the next step was to combine them into one component. Attaching the two was a pretty straight forward process, I just lined up the stick arm so that it was centered over the top of the bucket and then used the 1" L brackets to join the two pieces together. To ensure a strong connection I used 3 L brackets to attach the stick arm to the bucket. I made sure to use the longest allowable screws to ensure a strong connection here, additionally I added some wood glue between the two parts for some extra strength.
Step 11: Attaching the Stick Arm and Bucket Assembly to the Digger
Alright, if you've made it this far then you're almost at the home stretch. Connect the stick arm and bucket component to the rest of the sand digger in a similar fashion to how you connected the boom arm. Included on this step is a diagram of how the parts should be bolted together, as well as an example of what everything should look like up until this point.
Once the stick arm is attached to the boom arm you will need to create a connector to link the stick arm to the handle that was installed with the boom arms. This connector is just a simple 30" length of pallet deck board and should be installed so that when you push the handle forward the bucket moves towards you and when you pull the handle backwards, the bucket moves away from you. Play around with it until you are happy with the movement of the parts.
Note: If your handle placement feels strange or uncomfortable when operating the stick arm you can adjust the length of the connector that links the handle to the stick arm. Lengthening or shorting this piece will directly affect how you need to operate the handle to maneuver the bucket.
Step 12: Attaching the Handle for the Boom Arm
Okay, so this is the last step where you actually have to build something. All you have to do here is to bolt the remaining handle to the boom arm as shown in the picture. Where the other handle was installed so that it could pivot, this one needs to be installed so that it is firmly fixed to the boom arm, that way you can control the movement of the boom arm by pull back or pushing forward on it. To bolt it into place I used two 1/4" lag bolts.
With the last handle installed your sand digger is basically complete, so take a moment to hop on and test it out. Once you're pleased with how it works, the next step it to take the whole thing apart for painting.
Step 13: Painting!
Sorry to make you go through all of that work building the sand digger only to make you take it apart, but it is much easier to paint after you have all the parts cut and are sure that they work together. Note that painting is optional and isn't terribly necessary as pallet wood is already treated to endure the elements, but painting does help your project to look finished and polished and the added protection the paint provides will help your project to look better for longer.
To paint this project I tried a new type of spray paint from Valspar. it was a matte finish yellow paint and primer and I have to say that I am actually really impressed with the results. Generally I don't like finishing projects, whether I'm apply paint or stain, or polyurethane, I have a bad track record of messing up projects at the last minute via poor finish application. This paint however gave me no such trouble, despite the fact that the pallet wood was rough and largely un-sanded the paint went on without trouble and give a nice professional finish that enhanced the whole project. What's more, it was easy to apply and dried super fast, both of which are big in my book as I hate waiting for paint to dry and I don't like tedious paint application.
As for the black parts, I used black exterior house paint. it also went on without to much trouble and as this is a toy and not a fine wood working project, I didn't mind a few small imperfections in the finish.
Once the parts were dry everything was reassembled just as it had been previously.
Step 14: Finishing Touches
After painting and reassembly I added a few finishing touches to complete the sand digger.
Handle Wraps: As this project is mostly made from pallet wood splinters were always a major concern. Considering that the handles will experience the most human contact I decided to give them a wrap of paracord to reduce the risk of splinters. As an added bonus it also looks cool and makes the handles more comfortable to operate.
Spring Assist. I tend to over build things and this project was no exception. I built it with my 5 year old nephew in mind and unfortunately when he went to operate it he could barely lift the bucket from the ground. So to fix the problem I added a spring assist to the boom arm by attaching a heavy duty coil spring between the boom arm handle and the carriage. this spring helps to offset the weight of the boom and stick arms and allows him to easily lift and maneuver the digger.
Flange Bolt Covering: The bolts that attached the flange to the carriage were unsightly so I covered them with a small piece of wood.
Painted Decoration: Once the sand digger was finished it was cool but it was also a little generic looking. to give it some personality I painted on stripes and some fake equipment logos. All the decoration painting was done with black acrylic paint and was sealed with matte finish polyurethane.
Step 15: Go Play!
Once the paint has dried and all of the finishing touches are done, your sand digger should be ready for action. Set this puppy up by your sand box or load it in the car and take it with you to a local park or even to the beach and watch in amazement as kids pop out of the wood work eager for a chance to give it a try. Thanks for taking the time to check out my Instructable, This was a fun and simple project that was really easy to build and best of all I only had to spend around 25 dollar to put it together. I hope you enjoyed this Instructable and if you you're thinking about tackling this project I encourage you to give it a shot as it is really worth the time it takes to build. Thanks again and if you have any questions, please feel free to leave a comment and I will do my best to get back to you asap.