How to keep Screwdrivers in their Holder

[gatz]

I've had this handy Craftsman screwdriver/nut-driver set since the early 70s, and every time I go to use certain interchangeable drivers, the darn things won't stay in the holder. I've used tape, folded paper and anything else I could think of to stop those drivers from falling out of the holder.

Finally thought of using a ball plunger. I looked for a smallish SAE size, but found that metrics were much easier to source and cheap.
I chose M4-0.70 x 8.
After making sure a tapped hole would not hit the shank within the driver, I tapped the hole M4-0.75.
This caused the ball plunger to hold very tight, so no further adhesive was required. The ball plunger can be adjusted for fit.
There were only 2) drivers in the set that had the looseness problem, but it worked out great.
Very little effort is needed to insert a driver.

gatz