Universal Broken Bolt Drilling Guide Set for M6, M8 and M10 Studs and Bolts

Universal drilling guide set for accurately centre-drilling or drilling out broken bolts and studs on almost any suitable component.

When the correct tapping-drill diameter is observed, the guide allows sufficiently precise drilling that the remaining bolt material can often be removed from the original thread with a tap.

The set contains three interchangeable drill guides for 3, 4.5 and 6 mm drill bits. They are held and centred by a drilling jig attached to nearby mounting points.

Each drill guide also has a recess that can be positioned directly over a protruding broken stud for accurate centring.

Mounting Options

If only one suitable mounting point is available nearby, the included single-point drilling jig can be attached to one bolt hole.

For mounting points positioned farther apart, the adjustable butterfly guide can be secured to two studs or bolt holes. Its two sliding guides allow the drill guide to be centred precisely over the damaged fastener.

Application

1. Select adapter sleeves matching the available M6, M8 or M10 mounting points.
2. Attach the appropriate drilling jig to the nearby mounting point or points.
3. Adjust the jig until the drill guide is positioned exactly over the centre of the broken bolt or stud.
4. Select the drill guide matching the required drill-bit diameter.
5. Depending on the strength of the fastener and the quality of the drill bit, drilling may need to be performed in several stages, starting with the smallest diameter.
6. The drill-guide sleeves can be exchanged without changing the alignment of the jig.
7. Observe the correct tapping-drill diameter when removing the remaining fastener material.

Recommended Drill Bits

For accurate drilling, we recommend the following ground HSS-E cobalt drill bits:

• Item no. 122625 – 3 mm HSS-E DIN 338 cobalt drill bits, ground, 2 pieces
• Item no. 122628 – 4.5 mm HSS-E DIN 338 cobalt drill bit, ground
• Item no. 122631 – 6 mm HSS-E cobalt CO-5 special drill bit, ground

For drilling in confined installation spaces, we recommend the pneumatic angle drill under Item no. 52002.

Suitable Applications

• Broken studs and bolts
• Fasteners broken flush with the surface
• Fasteners broken below the surface
• Cylinder head studs
• Exhaust manifold bolts
• Engine blocks and housings
• Other components with suitable nearby mounting points

Scope of Delivery

• 1 drill guide for 3 mm drill bits
• 1 drill guide for 4.5 mm drill bits
• 1 drill guide for 6 mm drill bits
• 2 M6 adapter sleeves for mounting the guides
• 2 M8 adapter sleeves for mounting the guides
• 2 M10 adapter sleeves for mounting the guides
• 1 single-point drilling jig for mounting to one bolt
• 1 butterfly drilling jig consisting of two sliding guides for mounting to two studs