Step 3: Layout the Boom once cut from the Donor Bike
Prepare to drill the Head-tube* sized whole that will be the miter (sophisticated, snug joint where two objects join at an angle).
The boom is positioned on head tube to see where to drill miter hole. The drill with attached hole saw** bit is positioned to convey the idea of mitering.
* Headtube is the pink frame's front frame tube through which the bike's fork steering tube passes.
** Hole saw bit is the 1.5 inch diameter white toothed cylindrical saw in the drill chuck.