Real problems, real solutions, no fluff. I have spent years working across multiple shops running gun drilling, BTA drilling, and ejector drilling machines — setting up jobs, troubleshooting coolant pressure and chip evacuation issues, drilling deep holes in everything from hydraulic cylinders to aerospace titanium. This site is where I share what I have learned.
I have spent a lot of years watching machinists blame the tool, the feed rate, or the material when the real culprit is sitting right in the coolant tank. Coolant for deep hole drilling is a chemical cocktail, and each additive serves a specific purpose. Understanding what each one does and how they interact is the difference between a process that runs all shift and one that burns through drills before lunch. Here is what I have learned, the hard way. ...
Deep Hole Drilling for EV Battery Cooling Plates: Challenges and Solutions Over the last few years, I have seen battery cooling plates become one of the fastest-growing applications in our deep hole drilling shop. Every major EV platform now uses liquid-cooled battery packs, and the cooling plate — typically a sandwiched aluminum assembly with internal coolant channels — is at the heart of the thermal management system. As demand has ramped up, so have the calls from manufacturers asking how to adapt deep hole drilling processes to these parts. The short answer is that it works very well, but you have to rethink almost every assumption you carry over from traditional deep hole drilling work. ...
Deep Hole Drilling Hardened Steels (HRC 40+): Parameters and Tooling That Work Hardened steels are a different animal. I learned this the hard way — watching a brand-new carbide gun drill snap on the third hole because I treated the material like it was standard 4140. After a lot of scrap parts, broken tools, and late-night spindle-side debugging, I landed on a set of parameters and tooling choices that turn hardened steel deep-hole drilling from a gamble into a repeatable process. Here is what actually works on the floor. ...
I have been through enough machine purchases to know how easy it is to get the decision wrong. A deep hole drilling machine is a six-figure capital investment that will shape your shop’s capacity, quality, and cost structure for the next decade. Over the years I have been involved in several acquisitions – some that paid for themselves in eighteen months and others that became expensive lessons. The difference was almost always how rigorously we evaluated the options before signing. This article walks through the framework I now use every time. ...
Why Magnesium Is Different from Aluminum If you have ever drilled aluminum at production scale, you know the common headaches: built-up edge, stringy chips that tangle around the tool, and the need for high-pressure coolant to break those chips. Magnesium is in a completely different league. Magnesium has one-third the density of aluminum and roughly half the Young’s modulus. Cutting forces are dramatically lower. The coefficient of thermal expansion is higher, which means the hole closes in on the tool faster as it cools. But the biggest difference is how it burns. ...
I have spent years dialing in gun drilling parameters for steel, aluminum, and titanium. When the first batch of PEEK medical components landed on my desk, I assumed the same principles would apply with lighter cuts. I was wrong. Plastics and composites behave fundamentally differently under the cutting edge, and deep hole drilling amplifies every one of those differences. Here is what I have learned the hard way so you do not have to. ...
When I first started deep hole drilling tool steels, I assumed they would behave like the hardened alloy steels I was used to. I was wrong. Tool steels are their own category of misery — high carbide content, through-hardened to the core, and absolutely unforgiving of parameter mistakes. After years of gun-drilling D2, A2, S7, and O1 for mold and die work, here is what I have learned the hard way so you do not have to. ...
How Ejector Coolant Flow Works: Inner and Outer Tube Before you can troubleshoot an ejector system, you have to understand how the coolant actually moves through the tool. I spent my first year working on ejector drills thinking the coolant flow was similar to BTA – and I paid for that assumption with scrapped parts and broken tooling. Ejector drilling uses a dual-tube system. The outer tube carries the drill head, and the inner tube runs concentrically inside it. Coolant enters the system at the outer annulus – the space between the inner and outer tubes. About two-thirds of the coolant flows forward to the drill head, where it exits through the clearance gap between the drill head and the bore wall. This forward flow lubricates the cutting edges and guide pads, and it carries chips back along the flute area into the outer tube annulus. ...
How BTA Machines Differ from Gun Drill Machines for Gun Drilling I have spent years running gun drills on both dedicated gun drilling machines and BTA machines, and I can tell you they are not the same animal. On a dedicated gun drill machine, everything is optimized for the gun drill’s operating principles: high coolant pressure at moderate volume, steady spindle speeds, and a rigid guide bushing setup that keeps the drill tip centered before it enters the workpiece. ...
Gun Drill Entry Bushings: Selection, Clearance, and What I’ve Learned About Getting the Start Right I have been working with gun drilling systems for long enough to know where the real problems hide. After years of chasing burrs, wander marks, and scrapped parts, I can tell you this: the entry bushing gets blamed for nothing and causes everything. I have traced more straightness problems to a worn or mismatched bushing than to anything else on the machine — coolant pressure, spindle alignment, even drill geometry all get more attention, but the humble bushing at the start of the hole is where the cut is won or lost. This article covers what I have learned about choosing, fitting, inspecting, and maintaining them so you stop fighting the first few millimeters of every hole. ...