My partner uses essential oils and makes her own blends.
The 20mm bottles she uses don't fit any of her racks so I made her one from an old table leg.
This is now my third.
Step 1: What I Used
Wood, this one is 125x60x60mm
22mm wood bit
Drill press with 2 axis vice
Step 2: Marking
Mark out where you want the holes.
On this one I worked out I could fit eight bottles
Step 3: Drilling
If you want different depth holes drill one row at a time.
Step 4: Broke It
While taking out of vice I dropped it onto the concrete floor and an edge broke off, but I was lucky it was the top front edge.
Step 5: Finishing Off
Sanded all the stain off and painted it with a high gloss black paint.
You could put a soft material underneath to stop scratches.
The other two I made were sanded the I applied beeswax to them.