Through-hole assembly introduces leaded components into plated holes and solders their connections. Mixed SMT and through-hole boards need a planned sequence and clear mechanical requirements.

Check holes, leads and fit

Provide component drawings when lead dimensions, pin patterns or body seating affect fit. Finished hole tolerances matter more than nominal drill size alone. Identify press-fit parts separately; they are not interchangeable with ordinary soldered insertion. Include connector orientation, mounting hardware and clearance constraints.

Agree the soldering approach

Thermal mass, board thickness, component placement and access affect the suitable soldering process. Identify heat-sensitive parts and requirements for lead trimming, standoff height and board support. Confirm process availability for the actual assembly instead of assuming that a generic capability list covers every geometry.

Inspect mechanical as well as electrical features

Specify acceptance criteria for solder joints, seating, alignment and any fastening operations. A connector can be electrically continuous but mechanically misaligned. Include mating or enclosure checks when relevant, and define any cleaning, coating or protection steps in the quoted scope.