Choosing the Right Lathe Size for Gunsmithing: A Comprehensive Guide

What is gunsmithing, what tools does it require, and what size of lathe is the best? This article explores the art of gunsmithing, while answering those questions.

WHAT IS GUNSMITHING?

Simply put, gunsmithing is the art of repairing, modifying, or even creating custom firearms. Gunsmithing combines some of the skills of old-fashioned blacksmithing with modern machine-shop techniques. Today’s gunsmiths often work in licensed gun shops, servicing new or used firearms, or they might be hobbyists wanting to learn how to perform basic repairs and customisations on their own. 

WHAT TOOLS OR REQUIREMENTS DO I NEED?

Most of the tools you might need for gunsmithing are your typical machinist equipment and accessories: brass punches, machinist’s hammer, and benchtop sander/grinder to name a few.

There are other more specialist instruments, but in general gunsmithing relies on relatively common machine-shop supplies.

That brings us to lathes, particularly gunsmithing lathes. One of the most critical, and certainly the most recognizable, parts of any gun is the barrel. A long metal cylinder, sometimes tapered, the barrel of a gun is simple, elegant, and requires careful crafting. The best way to work on a gun barrel is with a lathe, making a gunsmithing lathe almost a required piece of kit for both the professional and amateur gunsmith.

But when it comes to gunsmithing lathe, there are a number of questions:

• Why do I need a gunsmithing lathe?
• How powerful should the lathe be?
• How big should it be to fit the guns?

WHY DO I NEED A GUNSMITH LATHE? WILL MY REGULAR LATHE WORK?

A typical lathe looks remarkably similar to a gunsmith lathe, but it lacks one key component: a spider.

The spider keeps the gun barrel in place so it can be chambered or threaded. Additionally, a gunsmithing lathe will include:

• Spider bore/spindle bore
• roller tips
• different camlock chuck
• Outbound spider

For a metal lathe to also accommodate gunsmithing, it requires an adapter for the outboard side of the spindle, which can be removed when necessary. Each accessory allows for the detailed work on the gun to be completed safely and precisely.

When looking for a lathe, there are a few things to keep in mind. Lathes are massive pieces of equipment, but a reliable foot brake ensures that the machine stops when you need it to. A flood coolant system prevents the machine from being overheated and a heavy duty motor keeps the machine moving at a consistent speed. The heavier the lathe, the less vibration resulting in a steadier spider and a smoother job at completion.

BEST SIZE – SOME RECOMMENDATIONS

Let’s talk first about how to measure a lathe. Lathes are described by the size of the workpiece which can be turned on it. How big can a piece be, and still fit? With the typical arrangement of most lathes, this boils down to two practical measurements:

• The first measures from the center of the spindle, the rotating part which turns the workpiece, to the bed of the lathe. Let’s say that the distance is 7 inches. From the center of the spindle to the bed is half the size of a mounted workpiece, so the max diameter would be 14 inches. This is the “swing” of the lathe. 
• The next measurement describes the distance between the headstock and tailstock, or more accurately between a chuck mounted in the headstock and the tailstock. This is the “distance between centers,” or dead center. In practical terms it measures the maximum length of a workpiece.

Together, the swing and distance between centers provides a basic measurement for a lathe. If the swing was 14 inches, and the distance between centers was 40 inches, then the lathe would be described as a “14×40” lathe. 

For the aspiring gunsmith, the swing often isn’t as important; most parts of a gun aren’t terribly large in diameter. Gun barrels can be quite long, so the distance between dead center is critical.

A COUPLE OF FURTHER CONSIDERATIONS:

• Heavy duty gunsmithing lathes provide more stability, and therefore more accuracy and precision for cutting. Larger lathes allow more room between centers, but also carry a bit of extra heft. Of course, they are also more expensive.
• Not all work must be done between centers. There are ways to mount a barrel so that it passes through the tailstock with a chuck, allowing a gunsmith to work on barrels that are longer than the bed of the lathe. However, using a chuck dramatically reduces the diameter of a possible workpiece, so be sure that it’s still large enough to work.
• Always check on available rests for a new lathe – steady rests and follow rests, preferably with ball bearings – help stabilize long, slender workpieces like gun barrels.

RECOMMENDED LENGTHS FOR A GUNSMITH LATHE:

14×40 is one of the most commonly-mentioned sizes; large enough for more specialized work, but not impossible to find or fit in an average home-based workshop.

CONCLUSION

The size of a gunsmithing lathe is important, but the make and manufacturer is obviously much more so. Gunsmithing lathes are often just general machine-shop lathes, only slightly-modified for a particular application. As such, look for well-known and respected engineering equipment makers, with a reputation for accuracy and reliability.

Summit Machine Tool offers high quality equipment, with all the necessary specifications. Additionally, we also offer support, and parts and services if you’re looking for assistance with your lathe.