Holemaking Technology

Selecting the right holemaking tools for firearms manufacturing is key to improving efficiency while maintaining quality and precision. New technology improves straightness and finish, while reducing cycle times. Other innovations combine multiple tools, reducing cycle time and tool changes. Holemaking is a crucial part of all segments of firearms manufacturing, including rifles, shotguns, handguns, and revolvers. Holes must be straight, meet tight diameter tolerances, and have the proper surface finish.

Holemaking operations must be done quickly to meet manufacturer’s production demands. There are dozens of drilling, threading, and reaming applications on parts, ranging from barrels to sights, to upper and lower receivers, and slides. Most manufacturers are looking for a reliable process that gives them the capability to run more efficiently with minimal intrusion. This makes it easier to manufacture quality parts.

One of the most important machine requirements for the firearms industry is a high pressure coolant delivery system to help evacuate chips generated during hole drilling, which is critical to successful drilling as failing to do so may cause "walking", affecting hole straightness, and the finish. Innovative holemaking technology reduces cycle times, improves tool life, and reduces Total Indicated Runout, which affects hole diameter and straightness.

Engineers at Allied Machine (AlliedMachine.com) have developed tools to reduce TIR, enabling improved hole size and straightness. For example, the T-A Stealth Drill (because it runs quietly) was designed with an adjustable setup that removes runout. This enables the tool to drill straighter for longer, produce truer holes, and wear more evenly. The technology has been used for drilling rifle receivers and uses brazed guide pads for straightness, and a higher coolant flow capability to improve chip evacuation.

This design has also been found to reduce cycle times and increase feed rates compared to other drills. The T-A Stealth Drill was used by New England firearm maker that was experiencing issues with their current drilling process. They had a two-year contract for 10,000 rifle receivers per week and were having issues with hole concentricity in 30% of the parts.

Allied’s T-A Stealth Drill includes an adjustable locating pin and additional coolant outlets in the brazed carbide bearing area to decrease TIR and hole size variation. The new drill performed well, time of 40 seconds. The holder life is above 210,000 inches and the process is reliable, saving the customer $0.15 per piece and reducing one eight-hour shift per week from the job.

This drill design was also used for a major firearms manufacturer producing 9,000 shotgun barrels per week with parts made of 4140 low-alloy steel and 28-32 Rc hardness. The customer was experiencing TIR issues and insert/holder failures. Tool life was only 105 minutes (1,155 inches of life) with chip packing, requiring a peck cycle and providing a 125 finish on the part with poor hole quality and 30 percent reject rate.

The T-A Stealth Drill in combination with a newly-developed Ultra T-A drill achieved improved chip evacuation with a zero part reject rate. They got a 19 finish on the hole and tool life was increased to 170 minutes (2040 inches of life), an increase of 76%. The Ultra T-A insert is made from C1 carbide and uses Allied’s AM300 coating, increasing wear resistance and tool life.

Another innovation in firearms holemaking operations are high performance finishing tools, like replaceable head reamers, enabling manufacturers to produce more parts quicker. In an application making upper receivers for AR-style rifles, Allied uses its ALVAN line of replaceable head reamers to remove the need to hone or roller burnish parts in high production runs. The replaceable head reamer can achieve about 20 IPM, compared to standard reamers achieving only about 3 IPM.

Using ALVAN replaceable head reamers provides the required finish and size while increasing the feed rate and reducing cycle time. with insert tool life of 4,000 inches in 4140 lowalloy steel with a hardness of 32-35 Rc with a cycle New tooling maximizes machine speeds and better machines improve holemaking for manufacturers to improve their production quality. AG