HVACR115 – Mechanical for Gas Heat Sheet Metal Installation
Sheet Metal Tools • Sheet Metal Hammer
Tin Snips • Right Hand: Red Handle-cuts left • Left Hand: Green Handle-cuts right
Crimpers: Turns the end of metal pipe or fittings into a crimped male end for connecting.
Notchers: Used to notch corners of rectangular ductwork before bending.
Folding Bar: Makes 1” bends for flanges or ½” “ears” for connecting ducts with drive cleats
Duct Stretchers: Brings the “ears” of two ducts closer together in order to connect drive cleat.
Scratch Awl: Makes well defined lines in sheet metal when laying out fittings.
Adjustable Dividers (Scribers, Compass): Used to scribe radius angles on sheet metal.
Common method of connecting rectangular sheet metal ducts: • Using drive cleats and S-slip. • S-slip or S-locks slide over horizontal edges of one piece of rectangular duct. • Vertical edges are folded back ½” to form “ears. • Horizontal edges of second piece of duct are slipped into s-lock • Drive cleats are hammered onto the two sets of ears.
Flex duct cutter: Has knife for slicing flex membrane and insulation, and pliers for cutting spiraled wire. Comes with sheath. • Hint: Never cut wire with tin snips.
Sheet Metal Fabrication Machinery • Pittsburg (Lockformer) Machine: • One side of a piece of sheet metal is run through machine and formed to receive a ¼” edge on opposite side. • Flat sheet is bent into rectangle shape, • Pittsburg is opened slightly with screwdriver, • ¼” edge is inserted, • Pittsburg is hammered over, locking into place.
Break: Used to bend sheet metal. • Can be 8’ for shop, • Or 4’ to transport to job for furnace replacements. • Counter weighted for ease of operation. • Never place hand between upper leaf and bending leaf.
Shear: Used to slice sheet metal. • Can be pneumatic with foot pedal, • Or operated with foot lever.