Copyright True Blue Line Boring

Mobile Line Boring


True Blue Line Boring offer in-situ bore welding and machining of bores ranging from 40mm-1m and above. We run top of the range Climax boring equipment. We carry all the equipment in a purpose built trailer so that we can come to you any time anywhere.



True Blue Line Boring is a fully mobile service based in Brisbane. Being a mobile service allows us to travel to our clients throughout all of Queensland and Northern New South Wales. Although the majority of our work is between the Gold Coast and Sunshine Coast, we have travelled as far West as Charleville, North to Mackay and South to Coffs Harbour.



Mobile line boring is usually required when the component that needs to be repaired or machined cannot be transported or is too big to fit into a conventional machine for machining. Symptoms showing the need for line boring could be visual like excessive movement within pivoting components or cracks showing due to wear around pivoting components. It could also be audible like clunking, grinding, squeaking or rattling noises while moving pivoting components.


Harsh environments like in sand and lack of grease usually leads to pin and bore failure which creates rapid excessive wear. Over working or overloading machinery can cause pin and bore failure too. The amount of acceptable wear is governed by the tolerances applied to that specific component. Generally with earth moving, pin bores have clearance of one thou (0.001”) per inch of the pin diameter, so a 4” pin (approximately 100mm) will have 4 thou (0.004” or 0.1mm) clearance on the pin. Other industries do require tighter tolerances and in some cases an interference fit is required where the bore is slightly smaller than the pin so the pin needs to be pressed in.


The client is generally responsible for supplying engineered machine drawings with machine tolerances so a desired finish can be achieved. Newly engineered or fabricated components that require welding processes experience distortion and warping due to the excessive heat. Any pin holes on the component are left undersized to allow for machining then if required the components are stress relieved otherwise after the component has cooled off to the ambient temperature the line boring process can be done. In this way complete accuracy can be achieved for any pin hole size and position.


Being in the industry that we are in there is a high level of safety required. We have developed Safe Operating Procedures (SOP’s) and Job Safety Analysis guides (JSA’s) to adhere to these requirements. Most customers require our contractors to run through a safety induction before commencement of work.


All workshops have minimum requirement for safety apparel to be worn at all times. There are standards when it comes to both machining and welding processes. There are machining tolerances that need to be adhered to depending on the item being machined. Different materials need to be identified so that the correct tooling, cooling, speed and feed can be used. Welding different materials also require the correct procedures be used including pre-heating temperatures and correct welding wire or electrodes. Welding procedures can be purchased from many sources.


In order to function as a mobile line boring service we require certain resources. Firstly we use the support of the agent that sold us the line boring and bore welding machines. These machines require maintenance and replacement parts after a certain period of use. There are also many different accessories available for different configurations and processes while line boring/bore welding.


We buy welding gas for the welding processes that are required and also buy consumables such as welding tips, welding wire, a wide range of abrasive discs, flap wheels, welding helmet parts, welding machine parts and numerous other consumables from several welding suppliers. We use numerous engineering suppliers to provide us with any tooling required for machining including cemented carbide tips, carbide inserts, insert holders cutting compounds, cutting coolant, measuring equipment and many other engineering requirements. We are supplied by a safety work wear shop with high visibility clothing, steel capped boots, hearing protection, eye protection and numerous other items of safety apparel.


We also require pins and bushes to be engineered to complete a job, so we utilise the services of an engineering firm locally. On occasions there are different Field machine tools required to do in-situ machining processes in fact there are too many to own. We hire field machine tools from hire companies to complete the work required. Some tools that are available are: Flange facing tools, Journal Turning Lathes, Clamshell tools, portable Mills, Bevelling tools.


  • Measure bore to be repaired and choose the appropriate bearing mounts for the job
  • Remove all grease, rust or paint from the faces of the holes to ensure no porosity while welding
  • Set up bearing mounts and bar roughly to the centre of the hole/holes using three jaw set up chucks, discs or cones (whichever is more appropriate) and tack weld the bearing mounts in place
  • Fine adjust the bar to the correct position in the hole/holes by measuring from a datum point
  • Set up the boring machine and if welding is not needed or after the welding process is complete then machine the bore to the required size. If bore welding is required then bore the holes making sure that there is a clean cut all the way through to remove any rust or impurities that may affect the welding process
  • Remove the boring machine ready to bore weld


There is a large range of tooling required: Mobile line boring machine, bore welder, flange facer, clamshell tool, journal turning lathe, mobile mill, 3 phase welder, single phase welder, dial indicators, internal micrometers, external micrometers, internal callipers, external callipers, grinders, measuring equipment and basic hand tools.

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