Introduction: How to Install Figure 8 Table Top Fasteners
As their name suggest, Figure 8 fasteners are generally used to safely and securely fasten the solid wood top of a table to its solid wood base.
In this instructable, I want to walk you through the simple steps to install them, and share something I haven't seen many talk about: exactly where on the base you should place your figure 8 clips.
Step 1: Measure & Mark the Base for Fasteners
The first step is to lay out where the fasteners will go. Set a marking gauge, a combo square, or a ruler like I have here to just smaller than the radius of your figure 8s.
The fasteners I bought have a five eighths inch diameter, so I’m setting my ruler to just less than the radius of 5/16”. This will allow the fastener to pivot easier, which is how it protects from potential damage caused by wood movement.
Where to Install Figure 8 Fasteners on the Base
Notice I’m only marking on the short stretchers of the base. The purpose of these fasteners is to pivot to allow for seasonal wood movement, and the short stretchers are the best place to do that. Generally speaking, you’ll always want to install figure 8s on the stretchers that are perpendicular to the grain lines on the top, because that’s the direction most of the wood movement will occur.
Also notice that I’m marking the inner side of the rails. Doing this will hide the fastener in the final piece.
With all of the spots marked, I can come back with an awl to make a starter hole for my forstner bit.
Step 2: Drill a Shallow Recess With a Forstner Bit
Although most figure 8s don’t come with detailed instructions, they do tell you to use a forstner bit the size of the diameter, or slightly larger, to make a shallow recess for one side of the fastener.
As you’re drilling, go slow and check the fit often. The figure 8 should sit just below the surface of the base. It can’t be too far below because it will need to contact the tabletop as well. So just sneak up on the fit and stop when the entire fastener is below the surface.
Oh, and you may need to knock off the ears of the recess with a chisel like I did here to get enough clearance, especially if the forstner bit you used is the exact size of the diameter. So do that now.
Step 3: Drill Holes for Mounting Screws on the Base
In the point that the forstner bit left in each recess, drill a pilot hole for the small screws.
Once all the holes are drilled, you can attach the clips to the base. I'd recommend using a screwdriver instead of a drill to drive the screws; you want to avoid stripping these small holes.
Step 4: Drill Holes for the Mounting Screws on the Top
With all the fasteners installed to the base, now we can mate it to the top. Lay the top upside down on a protective surface. Turn the base over and place it on the top.
Align the two, then mark for the screws on the bottom of the top. Remove the base for a moment, and drill the holes for screws. One tip to make sure you don’t drill all the way through the top is to use a piece of tape like I did as a depth gauge.
Step 5: Attach the Base to the Top With Screws
Return the base to the top, screw to attach, and you’re done. Now the table and the top are securely together while still being allowed to move independently. It's as simple as that!