Hi Andrew
When I built my 16'' Dob I went to my local cabinet maker who then cut an offcut to size in my case circular and also drilled a large hole in the centre for the centre bolt.When selecting the laminate make sure you have a raised pattern and not a pure flat surface. This was a few years ago and the total cost was $5 and worked well as the movement was very smooth.I used three 60mm circular pads the ones you can buy at the local hardware and come in different sizes and are sold for the application of being used under chairs and table legs to prevent scratching of floors.
