New Holemaking Technology Improves Firearms Manufacturing
Selecting the right holemaking tools for firearms manufacturing is key to improving efficiency while maintaining quality and precision. New technology is now coming on the market that improves straightness and finish, while reducing cycle times. Other innovations combine multiple tools into one, reducing cycle time and eliminating tool changes.
Holemaking applications in the firearms industry
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 manufacturers’ 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, one that is “process capable” –which gives them the capability to run more efficiently with minimal intrusion. This makes it easier for workers of all skill levels to easily manufacture high-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. Chip evacuation is critical to successful drilling. If the chips are not evacuating properly it may cause “walking”, affecting the straightness of the hole. Chip packing can also affect the finish.
Innovative holemaking technology reduces cycle times and improves tool life
One of the perennial concerns of firearms manufacturers is the issue of Total Indicated Runout (TIR), which affects hole diameter and straightness. New technology has been developed by the engineers at Allied to reduce or eliminate TIR, enabling improved hole size and straightness.
For example, an engineered special nicknamed the T-A®
“Stealth Drill” (because it runs so 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, which is critical in many firearms applications. The technology has been used for drilling the receiver in a variety of rifle applications. It uses brazed guide pads for straightness, and a higher coolant flow capability that improves 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 at a subcontractor in New England for a firearm maker that was experiencing issues with their current drilling process. They had a 2-year contract for 10,000 rifle receivers per week and were having issues with the concentricity of the hole. Thirty percent of the parts failed a concentricity test.
Allied’s Engineers recommended the new T-A Stealth Drill. The design 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 very well, with insert tool life of 4,000 inches in 4140 low-alloy steel with a hardness of 32-35 Rc with a cycle time of 40 seconds. The holder life is above 210,000 inches and the process is extremely reliable The switch to the T-A Stealth Drill saved the customer $.15 per piece, reducing one entire 8-hour shift per week from the job.
Another example of the use of the new drill design was for a major firearms manufacturer producing 9,000 shotgun barrels per week. The parts are made of 4140 low-alloy steel with a hardness of 28-32 Rc. The customer was experiencing TIR issues and insert/holder failures. Tool life was only 105 minutes (1,155 inches of life). The tool also experienced chip packing, requiring a peck cycle. The tool provided a 125 finish on the part and hole quality was poor. The application resulted in a 30 percent reject rate.
With the T-A “Stealth Drill” in combination with a newly developed special drill nicknamed the “Ultra T-A drill,” they were able to achieve excellent 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 percent over the previous tool. The new Ultra T-A insert is made from C1 carbide, and uses Allied’s AM300®
coating, which provides excellent wear resistance for superior tool life in high penetration drilling applications.
Another innovation in firearms holemaking operations are high performance finishing tools, like replaceable head reamers. This enables manufacturers to produce more parts in a shorter period of time. In an application making upper receivers for AR style rifles, Allied uses its ALVAN®
line of replaceable head reamers. This tool removes the need to hone or roller burnish the part, making it a good choice for high production runs. The replaceable head reamer can achieve about 20 IPM, compared to the standard off-the-shelf reamer that can achieve only about 3 IPM. Using the ALVAN replaceable head reamer provides the required finish and size, while also increasing the feed rate to reduce cycle time. New tooling can help maximize machine speeds
Better machines make improving holemaking technology even more of a priority as manufacturers look for improvements in quality and throughput.