STCR26191/2-5M – STAPLES (5,000)

Bostitch STCR2619 series heavy duty PowerCrown staples, 1/2 in. leg and 7/16 in. crown, 5,000 per box. The standard staple for Bostitch T6-8 PowerCrown tackers.

Specifications published by the manufacturer. Source: manufacturer documentation.

Specs

• BrandBostitch
• SeriesSTCR2619 Heavy Duty PowerCrown
• Leg length1/2 in.
• Crown width7/16 in.
• Wire size0.026 in. x 0.019 in.
• Quantity5,000 per box

Cross-reference numbers

This part replaces the following OEM and aftermarket numbers:

• STCR2619

Not sure if your number matches? Call (214) 340-9421 or bring the old part in — bench-testing is free.

Sheet metal screw or wood screw?

Not interchangeable, and the wrong one costs you the joint. A sheet metal screw is threaded all the way to the head with a coarse sharp thread that cuts and holds in thin steel. A #8 by 1/2 inch hex washer head, driven with a 1/4 inch driver, is the workhorse for 26 to 30 gauge duct, and a #10 takes a 5/16 inch driver. A wood screw has a tapered, partly unthreaded shank meant to bite into fiber, so in 26 gauge steel it engages a thread or two and spins right out. Self-drilling screws are for heavier gauge, strap and angle, or going through two layers of metal.

How many screws per joint?

At least three on a round connection, spaced evenly around, then seal. Mechanical fastening is what carries the load. Tape and mastic seal air, they do not hold metal together. Flex duct needs a drawband or nylon tie at every collar in addition to the sealant, and that part is not optional.

What tape actually seals duct?

A UL 181 listed closure and nothing else. 181A-P foil tape or 181A-M mastic on duct board, 181B-FX tape or 181B-M mastic on flex and metal. Cloth duct tape carries no listing, is not an accepted closure, and in Berkeley Lab's testing it was the only sealant that failed outright, sometimes within days. Even good foil tape needs clean dry metal and a hard squeegee, or it releases in attic heat anyway.

Do zip ties matter?

In a 140F attic, yes. Use UV-rated black nylon. Natural white ties go brittle and snap, and then your thermostat wire or a flex collar is hanging loose.