Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Removing a broken bolt from a die-cast metal part (typically made of softer metals like aluminum, zinc, or magnesium) can be challenging due to the material's relative softness and susceptibility to damage. Here’s a concise, step-by-step guide to remove a broken bolt while minimizing damage to the die-cast part:

1.Assess the Situation:

Determine the bolt’s material (e.g., steel, stainless steel) and the die-cast metal (e.g., aluminum, zinc).

Check if the bolt is flush, below, or above the surface and whether it’s seized due to corrosion or thread damage.

Evaluate thread condition in the die-cast part to avoid further stripping or cracking the softer material.

2.Prepare the Area:

Clean the area around the bolt with a wire brush or degreaser to remove dirt, grease, or debris.

Mark the bolt’s center with a center punch to guide drilling (use a light tap to avoid damaging the die-cast material).

3.Apply Penetrating Lubricant:Spray a penetrating oil (e.g., PB Blaster, WD-40 Specialist Penetrant) onto the bolt and let it soak for 10-15 minutes to loosen corrosion or rust, especially if the bolt is steel in an aluminum die-cast part (prone to galvanic corrosion).

Repeat if the bolt is heavily seized.

4.Try an Easy-Out or Screw Extractor:

Select the Right Extractor: Choose a reverse-threaded screw extractor (e.g., Easy-Out) sized for the bolt diameter.

Drill a Pilot Hole: Use a left-hand drill bit (slightly smaller than the extractor) to drill into the center of the bolt. Drill slowly with low pressure to avoid damaging the die-cast threads, using cutting oil to lubricate.

Insert Extractor:

 Tap the extractor into the hole with a hammer, then turn counterclockwise with a tap wrench or socket. The reverse threads should grip and remove the bolt.

Caution: Apply gentle torque to avoid breaking the extractor or stripping the die-cast threads.

5.Alternative Methods if Extractor Fails:

Weld a Nut: If the bolt is flush or protruding, weld a nut onto the broken bolt (using a MIG or TIG welder) to create a new gripping surface. Once cooled, use a wrench to turn it out. (Note: Welding on die-cast aluminum requires care to avoid overheating and damaging the part.)

Slotting: For flush bolts, use a rotary tool (e.g., Dremel) with a cutting wheel to cut a slot, then use a flathead screwdriver to turn the bolt out.

Drill Out Completely: If the bolt won’t budge, drill it out entirely using a bit slightly larger than the bolt’s core diameter. Be precise to avoid enlarging the hole in the die-cast material.

6.Repair the Threads:

If the die-cast threads are damaged, use a tap to recut them or install a thread repair insert (e.g., HeliCoil or Time-Sert) to restore the hole’s integrity.

For HeliCoil: Drill the hole to the specified size, tap with the provided tap, and insert the coil using the installation tool.

Clean the area thoroughly after repair to remove metal shavings.

7.Prevent Future Issues:

Use anti-seize compound on new bolts to prevent seizing, especially with dissimilar metals (e.g., steel bolts in aluminum parts).

Ensure proper torque when installing bolts to avoid over-tightening, which can strip die-cast threads.