The positions of the tuning pins and front bridges (called nuts) must be accurately marked on the pinblock before the holes can be drilled and the nuts glued into position. While the pinblock can be drilled after it has been installed in the instrument, I prefer to do it pre-installation. The instrument's plan is attached to the pinblock using thumbtacks. Great care is taken that the plan is in the correct front/back and left/right position. Most of the plans I use have been digitized into a CAD program so that I can have copies printed at will. I drew this particular plan by hand and didn't want to destroy it. With a digitized plan, I would cut the pinbock area out of the plan and attach it to the pinblock with scotch tape. Using an awl, a small dimple is cut through the plan and into the top surface of the pinblock at the center of each tuning pin as they appear on the plan. Similarly, three or four small holes are drilled into the top of the nuts and they are nailed into position on the plan. The nails make small holes in the pinblock which are used to locate the nuts when it's time to install them.