Expansion bolts - blind hole applications

This innovative product replaces large fitted or interference fit bolts, no modifications required. Fast, safe and easy installation and removal.

Superbolt Expansion bolts for blind holes are radially pretensionable fitted bolts. As stud in tapped bore they replace fitted bolts, which are difficult to install and remove. The Expansion bolt for blind hole can be tensioned axially. Due to the radial pre-load, the joint experiences can increase in rigidity, therefore eliminating micro-movements between the parts. Our Expansion Bolts incorporate Superbolt multi-jackbolt tensioners and are fully mechanical elements and therefore reusable.

Expansion bolts

The Superbolt Expansion bolt for blind holes have been tested and approved by:

– ABS American Bureau of Shipping
– DNV Det Norske Veritas
– LRS Lloyd’s Register of Shipping

Above certificates are provided on a case-by-case basis. Ensure to specify required documentation prior to order.

Expansion bolt for blind hole (EBB) are made-to-order. Depending on your application, coating and special materials are optional. The team at Nord-Lock Performance Services will work with you to find the optimum solution. Contact your local Nord-Lock office if you wish to learn more about this solution.

Download the Expansion Bolt brochure here



Expansion bolt line drawings


Expansion bolts for blind holes, installation and removal:

Installation (Fig. 2):

  1. Insert tapered stud
  2. Insert tapered sleeve
  3. Remove backlash
  4. Set clamping stroke
  5. Tighten jackbolts on the incorporated Superbolt multi-jackbolt technology (Fig. 3)


Removal (Fig. 4):

  1. Remove the nut, use our removal tool to pull out the sleeve
  2. Remove the rest of the parts that are no longer under tension




  • Easy: Loose fit sleeves (up to .010″ – .020″ in the through-hole) are easily inserted even in holes misaligned due to rotation. Only hand tools are required for installation and removal.
  • Fast: Tightening requires only minutes per assembly.
  • Safe: Eliminates the need for special high powered tools and bolt deep freezing. Torque required is usually under 100 ft-lbs. Entire assembly requires only hand tools.
  • Economical: Saves money over alternative solutions in time and tooling. No need to ream/hone the bolts as normal machine precision is sufficient. Additionally, for precise alignment as little as two Expansion bolts can be sufficient. Loose fit through-bolts with MJT tensioners, can be used in the remaining holes.
  • Reusable: The split sleeve springs back to original size, use after use. Compared to the close tolerance solid sleeves found in other systems, the loose fit split sleeve is much less likely to hang up during removal.
  • Generates axial and radial force simultaneously. Easier to “pull together” coupling halves.
  • No reaming/honing required: Only line boring of holes is necessary.
  • No coupling face machining is required (where the nuts seat). The multi-jackbolt design compensates for small variations in perpendicularity of the spotface to the hole centerline.
  • Eliminate finish machine of sleeves on site: Generous sleeve expansion permits finish machining in advance.


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