Keep-Nut Undermount Sink Anchor Kit – 100 Sets, 1/4-20 2-Crown Inserts, 1-1/2 in. Posts
Keep-Nut Undermount Sink Anchor Kit – 100 Sets, 1/4-20 2-Crown Inserts, 1-1/2 in. Posts
The Keep-Nut Undermount Sink Anchor Kit is a set of 100 press-in anchoring assemblies for mounting undermount sinks to granite, quartz, solid surface, porcelain and other hard surfaces, each set pairing a 1/4-20 2-crown insert with a 1-1/2 in. Allen post, wing nut, star washer and Z-shaped sink clip. The insert seats by pressure alone in a plain drilled hole, with no resin, epoxy or adhesive and no cure time; its stainless crowns (teeth) bite the hole wall to give axial strength and flex, and the system averages 562 lb of holding strength per insert. Originally designed to support building facades, vertical wall panels and furniture, the insert works on granite, marble, engineered stone, UHPC, porcelain, solid surface, glass and composites, and is protected by U.S. Patent No. 10,473,141.
The holes can be drilled with standard shop tools: an 11.8 mm CNC drill bit, a 5/8 in.-11 11.4 mm manual grinder bit with stop collar, or an 11.8 mm drill bit with stop collar for solid surface. Whichever method is used, the hole is checked with the Go/No-Go depth gauge and the insert is driven with the setting tool; the drill bits, gauge and setting tool are sold separately and are not part of this kit. If you already own the posts, nuts and clips and only need inserts, the KEEP-NUT (Specialinsert) Threaded Insert – 6.5 mm Embedment Depth, 2-Crown, Medium Duty is the inserts-only 100 pack.
Key Features
- 100 complete sets: one insert, one post, one wing nut, one star washer and one sink clip per set
- Keep-Nut IM2S/P1.4-20/H6 press-in self-anchoring insert, 1/4-20 thread, 2-crown, 6 mm height
- 1-1/2 in. Allen post, wing nut and star washer, all 1/4-20 thread
- Z-shaped sink clip supports the sink rim from the post
- Quick assembly by pressure: no resins or adhesives, no cure time
- Average strength of 562 lb per insert
- Crowns (teeth) provide axial strength and flex for higher holding strength
- Works on granite, marble, engineered stone, UHPC, porcelain, solid surface, glass and composites
- Can be drilled with standard tools: CNC, grinder or by hand
- Specialinsert specifies a minimum material thickness of 8.5 mm (0.34 in.) for the 2-crown 6 mm insert
- U.S. Patent No. 10,473,141
What This Is Not For
This is not an adhesive or epoxy anchoring system and does not need one; do not glue the inserts in. It is also not suitable for material thinner than 8.5 mm (0.34 in.), where the insert has nothing to bite into. For a sink rim that sits closer to or further from the slab than a 1-1/2 in. post allows, Keep-Nut posts are also made in 1-1/4 in. and 1-3/4 in. lengths, sold separately. Drill bits, the Go/No-Go depth gauge and the setting tool are not included.
What's Included
- 100 x Keep-Nut 1/4-20 thread press-in self-anchoring insert, 2-crown, 6 mm height
- 100 x 1-1/2 in. Allen post, 1/4-20 thread
- 100 x wing nut, 1/4-20 thread
- 100 x star washer
- 100 x Z-shaped sink clip
Who Is This For?
Countertop fabricators and installers mounting undermount sinks in granite, quartz, porcelain, solid surface and other hard surfaces who want a mechanical, adhesive-free anchor that is drilled in the shop (CNC or grinder) and assembled at the job site, and who buy in production quantities of 100 sets.
Frequently Asked Questions
How many sets are in the kit?
100 sets. Each set is one Keep-Nut 1/4-20 2-crown insert, one 1-1/2 in. Allen post, one wing nut, one star washer and one Z-shaped sink clip, so every component is supplied 100 times.
Does the insert need adhesive or epoxy?
No. The Keep-Nut insert is assembled by pressure: it is pressed into a plain drilled hole with the setting tool and its crowns grip the hole wall. There is no resin, adhesive or cure time.
How strong is it?
The system averages 562 lb of holding strength per insert. The crowns, or teeth, give the insert axial strength and flex, which is what produces the higher strength compared with a plain press-fit.
What do I drill the holes with?
Any of three methods. On a CNC, use the 11.8 mm CNC drill bit. On a manual grinder or polisher, use the 5/8 in.-11 thread 11.4 mm manual grinder bit with stop collar. For solid surface with a hand drill, use the 11.8 mm drill bit with stop collar. In every case, check the hole with the Go/No-Go depth gauge before pressing the insert in with the setting tool. The bits, gauge and setting tool are sold separately.
What materials can it be used on?
Granite, marble, engineered stone (quartz), UHPC, porcelain, solid surface, glass and composites. Specialinsert specifies a minimum material thickness of 8.5 mm (0.34 in.) for this 2-crown 6 mm insert.
Why a 1-1/2 in. post, and are other lengths available?
The post length sets how far the sink clip can reach below the slab. This kit ships the 1-1/2 in. post; Keep-Nut posts are also offered in 1-1/4 in. and 1-3/4 in. lengths. Subtract the insert depth when working out the exposed post length for a given sink rim.