Low-Profile Drilling Guide Set for Broken M8 and M10 Bolts and Studs

Special drilling guide set for accurately drilling out broken M8 and M10 bolts and studs.

The adjustable three-arm guide positions the drill precisely over the centre of the damaged fastener. All components have a low-profile design, allowing the tool to be used directly in the engine bay where installation space permits.

The included depth stops can be set by measuring an intact threaded hole or fastener. This allows the broken stud to be drilled through without the drill entering and damaging the cylinder head, housing or other component beneath it.

Heavily seized or oxidized studs are generally easier to remove after they have been drilled through completely. The set allows the stud to be drilled progressively up to the largest suitable diameter, after which the remaining thread material can be removed with a screwdriver or hook.

Suitable Applications

• Exhaust and intake manifolds
• Cylinder heads
• Engine blocks and housings
• Gearboxes
• Differentials
• Axles
• Wheel-bearing housings
• Other components with broken M8 or M10 fasteners

Advantages

• Accurate centring over the broken fastener
• Prevents the drill bit from wandering
• Adjustable three-arm drilling guide
• Low-profile construction for confined installation spaces
• Depth-controlled drilling
• Allows progressive drilling from 4 to 8.5 mm
• Reduces the risk of damaging the original component

Application

1. Select the guide and mounting components suitable for the M8 or M10 fastener.
2. Position and secure the adjustable three-arm drilling guide over the broken bolt or stud.
3. Use the alignment sleeve or pins to centre the guide precisely.
4. Determine the permitted drilling depth using an intact threaded hole or fastener and set the corresponding depth stop.
5. Begin with the 4 mm HSS drill bit and enlarge the hole progressively with the 6.5 and 8.5 mm drill bits as required.
6. After drilling out the fastener, carefully remove the remaining thread material with a suitable screwdriver or hook.

Scope of Delivery

• 1 adjustable three-arm drilling guide
• 1 drill guide for 4 mm drill bits
• 1 drill guide for 6.5 mm drill bits
• 1 drill guide for 8.5 mm drill bits
• 1 depth stop for 4 mm drill bits
• 1 depth stop for 6.5 mm drill bits
• 1 depth stop for 8.5 mm drill bits
• 2 M8 x 1.25 mounting nuts
• 2 M10 x 1.5 mounting nuts
• 1 M8 alignment sleeve for positioning the guide on a protruding stud
• 1 M10 alignment sleeve for positioning the guide on a protruding stud
• 1 HSS drill bit, 4 mm
• 1 HSS drill bit, 6.5 mm
• 1 HSS drill bit, 8.5 mm
• 3 M8 guide sleeves
• 3 M10 guide sleeves
• 3 double-ended alignment pins for positioning the guide in existing holes
• 1 angled hex key, 2 mm
• 1 angled hex key, 4 mm
• 1 angled hex key, 5 mm
• 1 robust storage case

Available Replacement Drill Bits

The following replacement drill bits are available separately:

• Item no. 122627 – HSS-E cobalt 5% twist drill bit, 4 mm, 1 piece
• Item no. 122632 – HSS-E cobalt 5% twist drill bit, 6.5 mm, 1 piece
• Item no. 122636 – HSS-E cobalt 5% twist drill bit, 8.5 mm, 1 piece