Plaque mounting details
Milestone plaque mounting details
Each milestone plaque is 45cm x 30cm x 1.4288cm [18" x 12" x 11/16ths"], is made of bronze, and weighs about 8.4 kg [21 lbs]. The edge of the plaques have a flange and a bevel. The flange is 4/16s" or .635cm, and the bevel is 5/16s" or .7938cm.
The milestone plaques come with four mounting holes in the back. There are four at the corners: 2.75 inches/6.5 cm in from the corners (as measured on the diagonal) or 1.95 inches/4.596cm in from the edges. The holes are threaded to take the studs.
The studs are 12.5 cm long with a diameter of .75 cm. The washers are 5cm in diameter with 1 cm hole. Most common threading is 10/24 and 1/4x20.
We recommend waiting until you have the actual plaques in hand before drilling any mounting holes or preparing the masonry.
Below is a rough diagram of the plaque as seen from the back. The plaques used to come with 6 holes (two along the midline of the plaque. However, beginning in 2012, the foundry began casting them with just the four mounting holes at the corners. The diagram shown below shows the previous version in case anyone with an older plaque needs this information for remounting purposes. The midline holes were/are 4 inches/10.16 cm in from the side edges (or 5 inches/12.7cm from the center) and 6 inches/15.24cm from the bottom and top edges.
For photographs of Milestone plaque locations and installations (walls, pedestals, etc.) please see the bottom of Helpful Hints on Citations, Plaque Locations