Undercut anchors

KEIL Undercut Anchor

KARL Undercut Anchor

KARL® Undercut Anchor KH BH

520 020 ---

Anchor sleeve and grub screw with hexagon socket A4 and nut with locking ratchets made of stainless steel quality A4

D1 = drill hole Ø
D2 = undercut Ø
SW = shaft spanner gap
DS = nut head
XA = anchor hex

further dimensions on request

Product information

  • The KARL® undercut anchor consists of a self-undercutting anchor sleeve, a grub screw and a locking nut.
  • The anchor sleeve, compressed in the lower area, is inserted into the cylindrical drill hole.
  • Rotating, the anchor creates its undercut itself. This is done by inserting the pin of the setting tool clamped in the cordless drill in a path-controlled manner. The anchor is driven by means of the hexagon socket of the setting tool. The anchor sleeve is expanded to the initial dimension. Thus, it always lies fully against the self undercut area of the drill hole of the facade panel.
  • With slight pressure on the plate holder (to lock the anchor), the grub screw is screwed in. The locking ratchets of the nut dig into the plate holder as a screw lock. After assembly, the anchor is seated in the undercut hole without expansion pressure, i.e. the bracket can still be turned with a certain amount of force.
  • The drill hole, anchor sleeve and grub screw must be matched to the desired setting depth and the selected plate holder. Only the use of matching parts makes installation quick, easy and safe.
  • Screw on panel holder/ reveal angle with nut.
  • KARL® undercut anchors are externally monitored.


  • Fiber concrete
  • Fiber Cement
  • High-pressure laminate (HPL)
  • Compressed fiberboard

We would be happy to test the usability of our undercut anchor in your material as well.

Instructions for use

  • When screwed in, the threaded pin must fit flush with the tip of the anchor sleeve.
  • Use according to approval and assembly instructions for KARL® anchors.
  • Please find documents with relevance to building regulations under Technical Assessments.

Packaging unit


KEIL Fasteners

KEIL reveal attachment sets

Drilling tools

Diamond tipped façade drill bits

Carbide tipped façade drill bits

Drilling technology

Drilling machines

Machine Accessories

Spare parts

Assembly aids

Depth control guide

Assembly aids

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