At this point, you should have Parts Y and Z clamped with pilot holes drilled using a 1/8" bit. All of these holes will need to be drilled with larger drill bits, but there is a mixture of sizes and types of drilling to be done, so let's go slowly here.

Take a look at Figure 8-1. This shows the surface of Part Z. The six holes indicated are for bolts that will be inserted into Part Y and through Part Z, and secured using nuts on the bottom of Part Z. These six bolts will hold Parts Y and Z together securely. The holes you will drill here must be countersunk using a 1/4" countersink drill bit. This will allow the bolts to sit just below the flat surface of the table.

Figure 8-1. Part Z has a total of 16 holes drilled on its surface and 6 on the edges.

In Figure 8-1, the ten 7/16" holes drilled (five on the left edge and five on the right edge) are for inserting cross dowels. Insert a 7/16" drill bit and drill those ten holes using the pilot holes you drilled in Chapter 7. You'll also drill three 1/4" holes on the left edge and three 1/4" holes on the right edge where bolts will be inserted through the table legs and screwed into the cross dowels.

Figure 8-2 shows how Part Y will look when the 1/4"-20 X 1" countersink Phillips flat head screws, or tapered bolts, are inserted-we're not yet ready for this step; this photo is just so you can see how the countersunk holes will allow the 1" bolt heads to sit just below the surface. (You can also see the holes drilled on the surface for the cross dowels and the three holes drilled into the edges of Parts Y and Z where the table legs will attach-more on that later.)

Figure 8-2. Holes drilled into Part Y (and Part Z)

Set Part Y aside for a moment and grab Part Z. You'll be drilling holes in the bottom of Part Z (the surface that will be facing downward once the two halves are attached together). Using a 7/16" drill bit, drill the ten cross dowel holes as indicated in the plans (five on the left and five on the right). Drill 1/4" holes in the six holes that will be used to bolt the top and bottom table halves together. You can see Part Z in Figure 8-3 with these holes drilled.

Figure 8-3. Part Z with cross dowel holes and 1/4" bolt holes drilled

Next, you're going to need to counterbore the six 1/4" holes to a depth of around 1/4" and a diameter of 3/4"-this is shown in Figure 8-4. We recommend a 3/4" Forstner bit for this task, and it may require testing on some scrap pieces of wood to get the right depth set. You'll want to drill it deep enough so that the nut inserted into the counterbore will sit just below the surface.

Figure 8-5 shows how the bottom of Part Z will look when the nuts are added; notice they sit just below the surface.

Figure 8-4. Counterbore the six holes on the bottom of Part Z.

Figure 8-5. The bottom of Part Z with 1/4" nuts inserted into counterbored holes

Next, attach the two halves together. This is done by inserting six 1" tapered bolts (1/4" diameter) into the six holes on the surface of Part Y, and using 1/4" nuts to secure them. Tighten the nuts securely but don't overtighten.

Now that Parts Y and Z are attached, it's time to drill the holes for the table legs. Take a look at Figure 8-6. We've used a straight edge to extend lines from the five holes on the surface of Part Y to the table's edge. This is done so we can drill these holes to match up with the 7/16" holes that will hold the cross dowels. We've also drawn two straight horizontal lines halfway through the edges of both Parts Y and Z.

Figure 8-6. The tabletop with chamfered edges as seen from the end

Figure 8-7 shows a close up of the holes drilled on the table's edge. There will be six on one side and six on the other (three per half). Notice the lines drawn to help match up the proper location for drilling these holes.

Figure 8-7. Holes drilled into the table's edges will let you attach the legs.

Before we finish this chapter, we'll end by cutting out two ends (legs) for the table, Parts T and U. After cutting the legs, mark them as instructed in the CNC plans. Figure 8-8 shows the plans for cutting and drilling the legs.

Figure 8-8. Marking the table legs for drilling

Figure 8-9 shows one of the legs with drilling marks partially completed. Notice that we haven't yet drawn the marks for the larger hole on Parts T and U.

Figure 8-9. After marking the legs, double-check the measurements, as accuracy is needed here.

The two legs must be centered as perfectly as possible for the CNC machine to work properly. To help with this, we recommend extending the pencil marks shown in Figure 8-9 to the top edge of Parts T and U. Check to make sure that these pencil marks line up with the 1/4" holes on the table edges, as shown in Figure 8-10.

If the holes used to mount the legs to the table line up, finish up by marking the legs for the larger center hole to be drilled as shown in Figure 8-11. Extend the line for the 1/4" bolt used to connect the leg to the table down. This will ensure that the larger hole (see Figure 8-8 again) on Part T lines up exactly with Part U after the legs are connected to the table.

Figure 8-10. Make certain the legs are centered properly.

Figure 8-11. All the drilling marks completed for the table legs

At this point, you should have the following items completed:

For the work performed in this chapter, you will use

In Chapter 9, we'll finish building the CNC tabletop by drilling the legs, attaching them, and then adding the angled aluminum rail to the sides. When done, you'll have approximately one-third of your CNC machine completed!