Because the tobacco chamber's bottom should ideally be conical or rounded to aid consistent burning and ash collection, rather than flat as a typical Forstner bit would create, drilling it requires dexterity. This form lessens hotspots and enhances smoke quality by effectively directing airflow from the draft hole. For novices, cheap spade bits adjusted on a bench grinder (with careful grinding to provide a rounded edge and relief angles) or pre-rounded versions found online are adequate. Specialized chamber bits range in price from less than $10 to more than $100. Although 7/8-inch is the most common diameter for larger bowls, 3/4-inch is the most common for regular pipes. Always make sure that the measurements of your block and the indicated instructions are followed. Use a drill press for consistency and work carefully, checking your progress often against your draught hole. To prevent premature breaching, stop when the entire diameter of the airway is visible at the base of the chamber. Aim for 1.5 to 2 inches of depth; err on the side of shallow at first as you may deepen if necessary, but too much drilling could thin the walls. For freehand methods, transfer measurements with calipers or a straight edge to make sure the chamber precisely intersects the draught hole; if it doesn't, re-insert the draught bit to verify alignment without applying pressure. V-slotting the stem end is one variation that might improve smoke dispersal and stretch the pull across the mouth, briar wood pipe avoiding tongue biting. In the end, a well designed chamber not only improves the smoking experience but also allows for a variety of tobacco cuts, such as ribbons or flakes, by maximizing combustion dynamics.