Bolt Removal
& Thread Repair
Removing broken bolts and restoring damaged threads while preserving the integrity of critical structural connections
Uptower Service
Bolt Removal
How It Works Restoring Critical
Restoring Critical
Bolted Connections
Broken bolts in structural connections and between main components are critical for the safe operation and structural integrity of the wind turbine. Band any resulting damage to the threaded holesneed precise repair to function reliably and above all secure safe operation and structural integrity of the turbine. Bolts can get stuck (impossible to untighten) or brake for several reasons. Using our mobile precision tools we are able to remove basically all defective bolts, fast, precisely and efficiently.
We can also restore threads that may have become damaged by the broken bolt. Depending on the damage in each case, our experienced technicians and diverse equipment allow us several thread repair options.
We can drill a larger hole around the original thread and cut a new thread, or mount a helical insert. Alternatively, we can use depth to drill deeper and cut a new thread. In either case, we are able to achieve the same strength as the original thread.. Repairing a damaged thread is not just about drilling a hole and cutting a new thread. To ensure the integrity of the joint it is equally important to ensure the correct position and angle of the repaired hole and thread. Here our customers benefit from our long experience and specialized equipment. We can remove and restore all bolt/thread dimensions
Technical Specifications
Typical duration 1–3 days on site
Thread sizes M24–M64+
Positioning accuracy High precision alignment
Certification ISO 9001 | OEM-spec
Equipment Mobile drilling & thread repair system
Applications Towers, hubs, foundations
Expected lifetime Similar to original
ISO 9001HELICOIL INSERTSONSITE REPAIRSTRUCTURAL INTEGRITY
Repair Instead of Replace Restore damaged threads and bolted connections without replacing major components or structures.
No heavy logistics Repairs are performed onsite, avoiding transportation, major disassembly, and unnecessary component replacement.
Structural integrity Precise positioning and alignment ensure repaired connections retain the required tolerances for reliable long-term performance
REDUCED DOWNTIME Fast and efficient repair of bolts and threads on site that keeps the downtime of your wind turbine to a minimum.
How it works
Our process
01
Quotation request
The wind turbine maintenance technicians contact us to report that a bolt, often including threaded hole, requires repair. Our team responds within the same day and the repair job is discussed with the customer. Based on the discussion with the customer a quote will be submitted. The customer agrees to the proposal and the repair of bolts and threaded holess can start almost immediately.
02
Implementation
Our technicians usually start work in the morning, transporting the equipment to the specific location in the tower or nacelle. The team removes the broken bolt and repairs the damaged thread
03
Handover
The customer can immediately install a new bolt and tighten it. Based on the agreement we will submit a report for the repair works.
04
Follow-up
We offer customers a discussion with the technician who will carry out the next inspection. Our follow up program complies with our high quality standards.
FAQ
Frequently asked questions
Can broken bolts band damaged threads be repaired?
Bolts can brake due to several reasons. Often a broken bolt leaves a part in the thread which needs to be removed before a new bolt can be installed.
Some bolts are difficult to access and remove but CNC Onsite has specialized equipment which allow us to remove all types of bolts.
When a bolt brakes this sometimes damages the thread as well. These can also be repaired in most cases.
Typically the threads are repaired by drilling the hole deeper and cutting new thread or by enlarging the hole and make a bigger thread (afterwards use a larger bolt) or by installing a helicoil (to use same bolt size).
How are the bolts in the rotor blade repaired? How are threaded bushings repaired?
Broken blade bolts can be more difficult to remove as the bolt has to be extracted through the blade bearing. CNC Onsite has specialized equipment to extract broken bolts from the blade bushings.
Minor damages to the thread in the bushing can be repaired up-tower but if the thread is severally damaged it require further measures to repair it.
A damaged bolt or defective threaded hole has been detected. What is the process to repair it?
The customer, usually the wind wind park technicians, contacts CNC Onsite. CNC Onsite will contact you (often within the same day) to discuss the damage with you. Photographs of the damage often accompany the descriptions. CNC Onsite will assess the extent of the damage to plan course of action..
As soon as the customer agrees to the quote, the CNC Onsite team and wind turbine owner determine a date to repair the affected bolts and/or threaded holes.
How quickly can a technicians come to the wind farm/park to repair a bolt?
CNC Onsite’s repair technicians can be on-site , within a few days. Once the customer has agreed to the job we are ready to move out.
How long does it take to repair a broken bolt or a damaged threaded hole?
The time it takes to remove a broken bolt and repair the damaged thread is very much depending on bolt dimension and location, but often the actual repair work is done within hours or a day.
During the initial contact CNC Onsite will receive information about the specific bolt dimensions and location and based on this a quote including a timeline is submitted.
To optimize the repair process CNC Onsite will as part of the planning for job, go through the preparations needed in the turbine, the actual repair work and the final verification test.
What does it cost to repair a a blade bolt or a threaded bushing?
Each job is different. We make a budget for each project to give the customer full transparency.
Contact our team Let us find
Let us find
the right solution
Whether it's a repair, machining project, or custom machine solution, our engineers are ready to help you find the most efficient way forward.
