ANNISTON ARMY DEPOT, Ala --The Small Arms Repair Facility at Anniston Army Depot recently began a new test method for the 81mm and 120mm mortar gun tube.
The new method, which uses a video borescope and bore measurement accessory, allows technicians to view the inside of the tube and see a detailed view of the interior of the artillery tube. This allows the technician to inspect for gun tube stress corrosion cracking, which could cause the tube to explode.
“We, now, have the capability to not only inspect the outside of the tubes for cracks, but we can use the borescope to see inside of the tube and make sure there are no cracks there,” said Jeff Dodgen, small arms supervisor.
Previously, technicians only inspected tubes for cracks on the outside using a process called non-destructive particle testing.
Using this method, technicians submerge parts into a “bath” which consists of a mineral oil solution. Once parts are saturated, they are then magnetized before being placed under a black light. Under the black light, parts glow green, allowing any cracks to become visible under the light. This process is still utilized to inspect parts for outer cracks.
Now, with the addition of the video borescope and display, technicians are able to perform an inspection that makes their overall quality testing more thorough, which ultimately helps to provide safer artillery for Soldiers in the field.
In fact, the purchase of the borescope was due to safety. "It's important that we are able to check for this type of cracking," said Courtney Hammett, maintenance management specialist, who worked on the project. "The Soldier is actually firing this weapon up close, so it could be very dangerous if one blows up next to them."
The new borescope, which cost nearly $32 thousand, consists of a dual camera, a front and side view, which is inserted into the gun tube. Once inside, the repairer turns the borescope 360 degrees at two inch intervals to check for cracks, viewing the inside of the tube on the digital display screen. The digital display is also capable of capturing video and still images.
And to further ensure accuracy, the borescope inspection must be performed by two technicians.
“It’s good because if I find a crack inside the tube, another technician has to double check it,” Barksdale said. “That means each part is being tested twice. Of course it’s a longer process, but it’s important that we get it right.”