Make their own boring bar out of hex steel bar and mount a small 1/4”dia HSS insert in the side, fixing with a grub screw positioned in the end. Hold the tube on a Mandrel at one end, centre the other (with plug), turn the outside then hold the tube in a 3 jaw chuck and bore out the inside...
Ten years ago I left precision manufacturing and started in field service engineering, mainly due to a downturn in jobs. However I worked in Precision Engineering For 20 years. I’m considering starting a small machining business but was wondering if I needed to have ISO9001 To get jobs.