This was a personal project over lockdown in 2020. The table incorporates two approximate straight line linkages on each side to create horizontal movement of the tabletop with minimal resistance, regardless of weight placed on top. I designed it quickly in SolidWorks although the cutting lengths are easy to calculate by hand.

To cut the semicircular ends on each link I built a jig. This holds a router on the underside and the pivot hole in each link end fits over the jig bolt, allowing the part to be rotated through the router bit.

Excess movement of the table is prevented by the transverse brace. This limits rotation of the short link (bottom right in the image above) to ninety degrees, resulting in table top travel of 200mm, around half its length.