On most builds the scales get drilled and roughed pretty quickly and don't get much attention. In this build, I wanted to step you through the process. This is how I do scales that need to line up very closely.
Start by laying out the L & R scales and finding that sweet placement. For this knife, I have the aluminum strip to act as a guide as it stands out between the two woods.
After marking the line of the aluminum strip or bolster-scale curve on to the knife, use this mark to align the scale pieces. Trace the tang shape and leave an extra 1/8" or so around the outside so we can sand it down perfectly later.
Over on the band saw, cut close to, but just outside the line.
Align and clamp the first scale. It doesn't matter if it's L or R. I used some vise-grips and my handy drill press block #3. Drill to match the tang holes for the pins. For this knife they are 1/8" and 1/4".
Another shot of how the vise-grip and block hold and support the two pieces while drilling. You don't want anything to slip or go off kilter here. Nice and perpendicular holes.
The holes in one scale are drilled.
Now, I cut some 1/8" wooden dowel. Each piece is about 1" long. Press the wooden pins through the scale and into the tang, but stop there.
Now the big alignment. Make 100% sure the second scale is lined up. In this case the aluminum strips have to perfectly match on the top and bottom sides. Clamp firmly with the vise-grips.
Remove one pin and drill through the first scale, through then tang and then all the way through the second scale. You can press the pin through again if you like, but the clamping force is holding everything together.
Repeat until all the pin holes are drilled. Press the wooden pins all the way through. Lightly tap them in if needed.
Now we can see the scales and how everything is going to line up. Inspect carefully and visualize where the tang sits inside the two scales.
Remove the pins and remove the tang. Using the same wooden pins, fit the two scales together. You can take some material off with the grinder as long as you don't go too far and into the scale where the tang is going to be.
As the two pieces are pinned, we can shape them together and match the fronts. Special care is given to the fronts of the scales as we won't be able to get into that area once it's all together. The ricasso of the blade will be right there.
Get the fronts of the scales smooth and polished.
From here we'll have to shape the handle when it's all epoxied up.