Next we need to layout the peg locations. This is more complicated that it may seem at first. Basically we are going to create a grid on the plywood and use the intersections as the peg locations. There are other seemingly more elegant and theoretically accurate methods of marking these locations (i.e. using a compass or a jig) but in practice, these are susceptible to cumulative errors and this is dangerous.

step 3a

With the plywood panel on your worksurface, lets begin the marking process. We will be making a 2" (50mm) wide frame that will will encroach onto the plywood area 1" (25mm) from all sides (a narrow strip of pine will be put on the underside of the pine that overhangs the plywood panel to hide the edge of the plywood). Make a line demarcating the area that the frame will take - in our case, this left a rectangle 19" x 58" (48 x 145cm)

step 3b

Now you need to decide how many columns you want to have in your plinko display. The rows of pegs are staggered so the number of columns increases and then decreases as you move down the display. We chose to make our model 6 columns wide which means that every other row is one less or 5 columns wide. (Note that if you choose an odd number of columns, the number of columns does not alternate, it remains consistent). The number of columns you select is not too critical but we would recommend a minimum of about 4. Increasing the number is fine, but each additional column you make increases the number of pegs which adds more time to the construction. We were very satisfied with 6 columns and don't see a need for more. Keep in mind that if you choose an odd number of columns, the sides will not be symmetrical and the exit pegs at the bottom of the display will not be centered. For this reason we recommend using an even number of columns such as 4, 6 or 8. As you proceed, consider that a display with 6 columns requires 7 pegs across.

step 3c

This is just an informational step to prepare you for the upcoming steps. In addition to the field pegs that make up the plinko display, you also need to include some pegs along the border to prevent the puck from getting caught along the frame. You could make the required scalloped shape by cutting into the pine frame, but we like the look achieved with the use of pegs. Note that we included extra side pegs that are not necessary; see the graphic on the right for an additional possibility.

step 3d

If you position the border pegs too close to the frame, they become difficult to paint when we reach the painting step, so we are positioning them 1/2" (15mm) within the inside of the frame. We made a mark along both sides; note that these marks are going to be the centerlines of the pegs. Next measure the distance you have between these centerlines and divide it by the number (we recommend using an even number) of columns you plan to have. We had 18" (45cm) which is perfect for the distance between peg centers to be 3" (75mm). Measure and make lines with a straight edge for these centerline distances along the entire length of the plywood panel. Now repeat this step by creating vertical lines at the halfway points between the existing vertical lines - these will be used for every other row of pegs. If possible, use an alternative colored pencil.

step 3e

Now we can start to make the horizontal lines. The location of the top and bottom row of pegs is not too critical, we just want to make sure that there will be enough room to insert the puck at the top of the display and remove it at the bottom. We used the center distance between pegs, 3" (75mm) in our case, and added 1" (25mm) and marked our top line this far from the inside edge of the frame. To prevent confusion we didn't make a complete line, but rather made hash marks at every other vertical line

step 3f

To mark the second and subsequent rows, use a compass and set it at your center distance. Draw an arc from two adjoining intersections - the intersection of those two arcs will be the location for your next horizontal line. Using either a large square or by measuring from the edge of the plywood, draw a hashed horizontal line to complete this row. Repeat this process down the plywood panel until you reach the bottom. You will need to leave at least the dimension that you left at the top of the display for the bottom; we omitted a row at the bottom to ensure that there would be plenty of room for the puck to exit.

step 3g

The final marking step is to mark the pegs for the border. We used a composite make large arcs along the both edges of the display. Then we reset the compass to 1/3 the distance between peg centers and made short hash marks to complete the peg locations. See the graphic on the right. We put two border pegs between each row but one would also suffice.

step 3h

The final step in the location marking process is to check the work you have just completed. A good idea is to make a small circle at each intersection that a peg will be located and then check that you have the accurate dimension between all of those intersections. In our case we set our ccompassat 3" (75mm) and verified the spaces between intersections. If you are off by a small amount, there probably won't be a drastic effect, but if one of the spaces is too narrow, the puck may get caught and that would be unfortunate.