5S is great for this, but here is what undermines every “first” lean implementation: accountability. There are several steps, but the first is to standardize the tool board or box so that you know what goes on the board and what is unneeded. That is the easy part. You also need a system where you can identify an out of control condition (i.e. a missing tool) in a few seconds. With a good shadow board or tool tray, one should be able to detect the missing 10mm socket in less than 10 seconds standing 10 feet away.
Here is what we did in my workplace and it works very well. We rarely lose tools, which is good because we use expensive tools. Think multiple digital torque tools, custom made torque wrenches, and high quality bits and sockets - everything is American, Ja-anesthesia, or German - you get the idea.
After we finalized the layout of the tool boards, every one has a card on it - green on one side and red on the other. You can use any visual indicator here. I helped a friend set up his machine shop and we used red and green solo cups. At the end of the shift, everyone puts the tools back on the board. We allow work to stop 15-20 minutes before the end of the shift so that everyone has time to clean up and organize. When everyone is done, the supervisor walks around and inspects every tool board. If nothing is missing, he or she makes sure that the card is showing green. This takes them about one minute for 10-12 tool boards. If a tool is missing, everyone looks for it until it is found. They look inside equipment, under equipment, etc. until the tool is found. Nobody is dismissed until everything is found. The incoming shift supervisor takes a quick look to make sure that all of the boards are “green” any may make the choice to “audit” the boards themselves. When they say that everything is good, then the employees are dismissed.
At lunch break, everyone turns their tool boards to “red” so that they know that the board has not been checked for the day.
This really works. Everyone is diligent about checking the boards because they don’t want to be blamed for a lost tool, but more importantly, they want to start the day with a full set of tools that makes their work more efficient and less frustrating.
I suggest that you implement this accountability system with something less critical, like cleaning the shop. It will take time to implement and get everyone in the habit, but everyone will be happier for it.