A 2x4 is will be used for the sand timer, it is a softwood and easy to work with.
The length will be 10 inches.
I marked the centres of the wood block and drew 2 channels. Note both ends have to be cut at 10 degrees. This will help the block pull over when the sand fills a channel.
A Miter gauge is set to 10 degrees and both ends of the block are cut. These can later be sanded to get the sweet point for tipping over after the sand is added.
To keep the cuts as neat as possible I started with a 1 1/8" forstner bit for each end then the rest can be cut using a jigsaw. The channels will be cut the same width.
A jigsaw can make the rest of the cuts but it could turn out a little rough. If it needs a little cleaning a file and some sandpaper will finish the job. Make sure you can see the pencil lines and stay as close as you can to them.
Now is a good time to drill the hole for the sand. I will use a wire for this.
The wire I used did not fit in the chuck of the drill so I cut a small piece of plastic from an electric wire and put it on the end of my wire drill bit and now it fits tight in the chuck.
Mini wire drill bit.
After the hole was drilled a piece of 3mm Baltic birch was glued onto the back. I always like to cut a piece bigger than I need and then trim it down and fine sand it later.
Sand was sifted to make sure it would be consistent in size so no large pieces would clog the hole. A large cup of sand was ready to use. I tested what I had so far to make sure everything was flowing from one side to the other.
I purchased a piece of plexiglass at a local plastic shop for $2.00. The Plexiglass was put onto the block and a Sharpie was used to mark where it had to be drilled. It was first drilled and then countersunk.
The sand timer is an easy build and so far I am using it in my shop for fun. The loud bang is makes a good alarm. It can be calibrated to get the exact time by adding or taking away sand and sanding the round edges.
Similar to the pomodoro technique I am using to do small chores around the shop like cleaning, sweeping or organizing a drawer.
Puzzle box Floating Dowel