Broken-Tool

Deep hole drilling is a high-risk process. When something goes wrong – a drill breaks in the bore, the bore wanders off position, or the surface finish is out of spec – the part is not necessarily scrap. I have salvaged thousands of dollars worth of components by knowing how to repair and rework bores. The key is knowing when a part can be saved and when it cannot. I have a simple rule: if the repair costs less than 60% of the replacement cost, it is worth doing. Anything over that and the customer is better off starting fresh. ...

Assessing the Breakage Before Extraction Every deep hole driller breaks tools eventually. When a gun drill breaks in the bore, the first step is not to panic. I assess the situation before deciding how to extract the broken tool. I ask myself three questions: where in the bore did it break, how deep is the broken piece, and is the tool jammed or loose. The location of the break matters more than most people realize. If the tool broke near the entry, I have more options. A break at the far end of a deep bore changes my strategy entirely. I use a borescope to examine the break point before committing to any extraction method. In my experience, thirty minutes of inspection saves hours of trial-and-error extraction work. ...