As my previous projects, this one is also around my son. I saw this sand digger somewhere on the internet and I decided to make it for him and hoped he will enjoy it. After some days usage I can confirm it is a popular garden toy :-)
Similarly to my earlier project I mostly used recycled materials to reduce the costs.

Part list:

An old car wheel (tire and rim)
Some metal (Hollow structural sections, details in the description)
Paint (I used black and yellow)
Screws
Welding
Wood (for the seat)

And finally you will need a sandbox where the children can play with this machine.

It has been created for a 3 years old kid, so the explained sizes fit for such children's body but you can adjust for your needs.

I wrote bunch of comments on the pictures to explain the details in place, so please read them as well.

Let's start it...

Step 1: The Basis

First idea was to remove the tire from the rim, but after some unsuccessful trying (without the proper tools) I realized I should not get rid of the tire because with it the basis will be more stable and the tire makes the toy more safer against the accidents.

I took a 20 mm x 20 mm x 400 mm metal rod and two 15 mm x 15 mm x 100 mm pieces and I welded them to the rim as you can see in the pictures.

On the other side of rim I made an another welding to make it stronger (it there is not on the pictures).

Step 2: The Grabbing Spoon

As I said I used recycled materials in this project, so I made the spoon from a waste metal part.

It is based on a 40 mm x 600 mm x 120 mm sized metal rod.

To make it, first I cut the one of the side of the rectangle shape then I created the teeth with angle grinder.
The next step is to close the ends of the spoon, I cut two shapes from a metal plate (I drew around the spoon on the plate to get the same shape) and welded them to the spoon ends.

I made a holder for the spoon from a small piece of 20 mm x 20 mm metal rod with a 6 mm hole for the screw and welded it to spoon, in this way you can calibrate the right angle of the spoon. You can see it on the 3D sketch picture. (last picture)

Step 3: The Skeleton

I found at home a metal tube and its inner diameter fits perfectly to the vertical base rod, so it can spinning around in 360 degree.
The seat is made from wood and fixed to the vertical tube with a metal plate with four holes for the screws.
Under the tube I placed a metal ring to make the spinning smooth.

The base of the arm is made from a 20 mm x 20 mm x 250 mm metal rod and it welded to the vertical tube. At the end of it there is a structure to accept the 15 mm x 15 mm x 600 mm moving arm. The axis is a screw - 6 mm diameter.

Step 4: Construction

In the first picture you can see all of the digger parts.

The second picture shows how the arms are fixed to the base. For sake of comfortable usage I made some bending on the arms as you can see it on the 6th picture. In this way there is bigger distance between the arms.

In the third picture is the spoon mover rod, I made a long cut with angle grinder to accept the rod and it is connected with a screw (screw diameter: 4 mm). To make a hole on the 6 mm rod I made the ends of it to flat with hammer (you can heat it before to make the process easier) then I drilled a 4 mm hole to this flat part.

To decide the right length of the upper rod I made some experiments manually. But you can adjust any miscalculation by change the position of the axis holes.

At the end of arms the handles are made by 3D printer but you can use any kind of same handles (e.g.: from and old bicycle).

Tip: You can use such screws nuts as on the pictures to make the usage safer for kids.