The original floor protectors were semicircular (ball shaped) plastic feet at the end of the tube leg. I decided to fix the chairs and to make them more "floor friendly". I used cabinet feet instead of previous round end plugs because I wanted more even weight distribution on floor due to increased footprint. Cabinet feet are also more durable, because cabinet weighs usually more than a chair and it's user.
Step 1: What Do You Need?
From the shop:
22 mm diameter end plugs, four per chair
Cabinet feet with 10 mm thread and tilting joint, four per chair
10 mm washers, four per chair
10 mm nuts, eight per chair
This you have probably before:
9,5 mm drill
Tool to remove the old protectors eg. pliers or a screwdriver
Step 2: Drill Holes & Remove the Old Floor Protectors
Then remove the old protectors from chair feet.