Clamping friendly hole clamps
The idea for hole clamps came from a German carpenter magazine called "Holzwerken.net". They presented a workbench with holes on the table surface and with a diameter of 20mm. Since I use the hole clamps for lighter jobs only, I decided to use a smaller diameter of 12 mm only. With smaller holes there is less risk to lose small bits and peaces falling through the holes. The first prototype was made with an old bar clamp and with a steel bar with a diameter of 12 mm. When using the clamp I noticed that the bar does not sufficiently clamp in the hole and that pressure of the clamp was not satisfactory. It was quickly clear, that the bar was not suitable for the job. I then went for a second prototype and replaced the steel bar with a threaded bar of the same diameter. The result was very positive. The clamps allow fixing any kind of material on the table and with sufficient pressure for any type of works.
I did only make holes in the table where I usually fix the material for work. I just wanted to prevent having holes everywhere on the table, just similar to a Swiss cheese.