Powers Spit-Lok Drop-In Anchor
Powers Spit-Lok (now manufactured under the DeWalt anchoring portfolio following DeWalt's acquisition of Powers Fasteners) is a flush-mount drop-in expansion anchor for the post-installed fixing of light to medium structural and non-structural elements to concrete substrates. The anchor is a malleable iron or zinc-plated steel internal shell, supplied in standard sizes M6 to M20, installed by drilling a pilot hole sized to the anchor outside diameter, dropping the anchor into the hole, and setting it with a setting tool that drives an internal cone to expand the shell against the surrounding concrete. The expanded anchor presents an internal female thread at the substrate flush surface for subsequent bolt fixing, which permits the connected element to be removed and re-installed as required. The anchor develops capacity by mechanical expansion against the surrounding concrete. Spit-Lok is supplied in mechanically-galvanised carbon steel and 316 stainless steel variants for varying exposure environments. TRSC specifies Spit-Lok for the post-installed fixing of services support brackets, light mechanical equipment, ceiling-suspension hangers, and other applications where flush-mount installation and bolt-removability are required and the load case is in the medium range.
Powers Spit-Lok occupies a specific specification slot in TRSC's anchor library: it is the flush-mount drop-in anchor specification where the engineering requirement is for a flush installation and a removable bolt connection rather than a permanent through-bolt or screw fixing. The product is selected over alternatives (Hilti HUS3 concrete screw, Ramset Trubolt+ wedge anchor) on three grounds: (1) flush installation — the drop-in anchor sits flush with the substrate surface, which is required where the connected element is plant equipment that must sit flat against the substrate or where through-bolt protrusion is unacceptable for architectural reasons; (2) bolt removability — the bolt can be removed and re-installed multiple times without compromising the anchor, which is required for plant equipment or services that are removed for maintenance; (3) lower unit cost on standard installations than equivalent-capacity injection anchors. The most common specification pitfalls TRSC encounters in the field are: (1) wrong setting tool — the anchor must be set with the manufacturer-published setting tool of the correct size; substituting a punch or generic tool produces under-set anchors with a fraction of the design capacity; the contractor must hold the correct setting tool inventory before the first installation; (2) under-setting — the setting tool must be driven until the internal cone is fully seated against the shell; field installations that stop short produce anchors with reduced expansion and reduced capacity, which may not be visually distinguishable from correctly set anchors; the contractor must demonstrate the setting force and the visible setting indicator on the first installation as a witness hold point; (3) cracked concrete — Spit-Lok carries cracked-concrete approval at reduced capacity compared to the uncracked-concrete capacity; in remediation contexts where the substrate is by definition not new concrete and may carry pre-existing cracking, the design must be against the cracked-concrete capacity unless the substrate has been investigated and confirmed crack-free in the anchor zone. TRSC anchor specifications include the product nomination, the anchor size, the embedment depth, the design load, the substrate condition (cracked / uncracked), and the substrate edge distance and inter-anchor spacing requirements.