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A Singer Car Crankshaft Showing A Hairline Crack While Undergoing A Magnaflux Test

Crack Testing

South Cerney Engineering offers crack testing on pretty much anything. Based between Cirencester, Gloucestershire and Swindon Wiltshire we are centrally located and easy to get to for NDT services.

The most common mode of failure for components is fatigue, the cyclic loading and unloading of a component causes crack propagation from a flaw in the material. The cyclic loading can be caused by heating cycles or forces repeatedly exerted on the part. Cracks commonly commence on the surface or just below the surface of the part.


Cracks, Voids, Pits And Subsurface Discontinuities Test Methods

Magnaflux testing is a process which can be used on a cleaned component and involves spraying the part with a solution and then inserting the part inside a very strong magnetic field, then by using UV light, flaws can be seen. Magnaflux testing is used heavily for initial crack detection.

For nonferrous (non-magnetic) materials a penetrant dye can be used. This involves cleaning the part followed by application of a test agent. Then followed by an intermediate clean, dried then the developer is applied to highlight the location of the flaw. Penetrant dye testing is very successful in many cases.

Another test method which can be used is to X-ray the part, this is ideal for safety critical components and if welds need to be checked for flaws, this method is unfortunately expensive and limited on size. X-ray of a component checks the entire component and if afforded is the best method although in many instances may simply not be necessary.  

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A helicoil gear being checked after suffering an impact

A con Rod passes crack testing checks

Components worth testing, What Can Be Tested

Pretty much anything can be tested. We regularly magnaflux or dye test the following items but have tested many other items as well

  • Crankshafts

  • Gears

  • Con-rods

  • Springs

  • Engine blocks

  • Pins

  • Suspension components

  • Wishbones

  • Uprights

Based between Cirencester, Gloucestershire and Swindon Wiltshire we are centrally located to offer crack detection NDT to a wide range of industries. 

“With rare or expensive parts,
it’s an excellent way of having some reassurance”


Possible Solutions To Seeing A Crack Or A Flaw In A Component


  • Once a crack has been identified there are several options available to address the problem, this depends though on many factors such as size of crack, location, costs.

  • The first possibility is to simply replace the component in question. However, this may not be realistic due to it being a vintage engine block of historical significance.

  • The second option depending how much the crack has progressed is to dress back the area locally to remove the crack on the surface. The crack maybe too deep though.

  • The third option is to dress back and rebuild with weld in the affected area. Again, this will depend on the part in question.

  • The fourth option is to arrest the crack from propagating by drilling the ends of the crack and then metal pin the holes.

  • A fifth option for arresting a crack is to metal stitch the crack, sometimes called metalocking. At South Cerney Engineering we have used metal stitch repairs successfully for many years on vintage engine blocks.  


Get in touch

Our friendly team of time served engineers can advise on the most suitable methods to be used to clean your parts.

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