Last week, after the Double Tap Championship, my dad, grandpa and I went on a tour of the STI International Factory, where the awesome pistols they make go from being bricks of steel into, well, THIS:

STI TruBor GrandMaster

I had arranged the tour in advance with Jay Dunlap, Sales Account Supervisor at STI, who ran their booth at the Double Tap. He gave us the tour.

Which amazed us. Not that Jay gave the tour himself, but how precise STI’s guns are. The amount of precision that goes into STI’s awesome guns is mind-boggling. They’re Uber-precise. I can’t come up with enough adjectives to describe how precise all the metal parts are.

Let’s start with the slide. All STI’s slides start as steel bar-stock. After the bar-stock is cut to the proper length, two holes are machined into the front of the slide (for the barrel and guide rod), as well as the guide rails. They are ground-down little by little by a HUGE grinding wheel until they reach the correct thickness.

Pretty big grinding wheel, yes? The pipe is to spew a lubricant to keep everything running smoothly.

The slides after being machined and ground down, about to be heat-treated.

After the slides are machined and ground down, they are heat-treated. STI is unique in that they heat-treat their components before they’re finished. when I asked why they would do that, Jay told me that they are heat-treated beforehand because all the precision put into the gun would be for naught if something were to warp in heat-treating.

After heat-treating (once they cool, obviously), the slides are machined further, machining just about everything else in various steps using both CNC and Wire EDM. Wire EDM (electronic discharge machining) uses brass wire to produce a spark, which is what actually does all the cutting. Wire EDM is the most precise method of machining one can use. CNC and plasma cutting doesn’t even come close to the precision one can achieve with wire EDM. The downside is that it is very slow, but perfection takes time.

A CNC machine at work.

A CNC machine toolhead. These blades and bits are change out automatically based on what is required by the computer design. Blink, and you’ll miss the swap. This is actually a small toolhead, with only 24 heads.

A wire EDM machine. the bin is filled with a rinse which the parts are placed in, near where the wire is brought down. This machine is making hammers, which can be seen on the screen.

On the other side of the building, STI’s single stack frames are made. Let me take a minute to explain the whole single stack/double stack thing. A “single stack” gun is one that takes a magazine that has bullets stacked one on top of the other, such as a 1911. A “double stack” gun takes a magazine that has bullets staggered atop each other, making the magazine wider, but holding more bullets. Sigs, and bricks, blocks, Glocks. are examples of double stack pistols. STI makes 1911 pistols as well as their own line of “2011″ double stack pistols, which retain the same form factor of a 1911, while using a wider, plastic, grip.

7 round 1911 magazine, compared to a 15 round Glock magazine.

Anyway, STI’s 1911 frames use basically the same slide as a 2011, but the frame is all steel. Most of the work is done by CNC machines, but all the frames must be deburred, all sharp edges rounded, and inspected by human eyes. all the deburring and rounding is done using hand files and Dremel tools.

1911 frames being loaded into a CNC machine.

Frames preparing to be deburred. Note that they are serialized. That is because they are legally considered firearms at this point. Also note the sharp edges.

Sharp edges being rounded with a dremel tool.

What is the one accessory without which one cannot shoot? That’s right, the magazine. STI’s magazines are made from two thin pieces of sheet stainless steel. These two pieces are stamped together and welded along the front and back. The weld marks are sanded down and the magazine tube is heat treated. The follower, spring, and baseplate are then added (again, AFTER it cools. Apparently a few people learned that the hard way).

Welds being sanded off.

Must… Resist… Urge… to steal…

Now, you can’t throw a bullet down range without that spirally tube thingy.  STI’s process of fitting their bull barrels to their guns is kind of a trade secret, so I won’t give anything away. Suffice it to say, they fit ‘em a bit differently.

Now, I said earlier that STI’s 2011 grip was made of plastic. That’s not entirely true. STI actually has a patent on their “modular grip frame”. The actual grip is made of injection molded plastic, but the upper part of the frame (where it meets the slide) is all steel. This upper part of the frame is made using CNC machines (boy, STI owns a lot of these things).

From right to left: Raw bar-stock, roughly machined bar-stock, more machining has been done, an actual frame with a bit of machining left to do (note that this piece is serialized, as it could be put on a plastic grip, assembled in a firearm and used as a single shot pistol), and a completed frame.

From here, all the components are sent to the fitting shop, where everything is fitted and assembled. Every single part of an STI pistol is fitted to that particular pistol. In theory, every STI part will fit in every gun of the same model. However, in order to enhance performance, no STI gun is alike. even small parts of little importance, such as the barrel link, are fitted. Is <insert part here>that important? Not really. Does it somehow affect the function of the gun? Slightly. It’s fitted. This is what differentiates STI from every other gunmaker. Most gun companies make sure a part fits. STI makes sure it fits perfectly. If it doesn’t, it’s fitted.

A station in the fitting shop, with all the tools necessary to ensure perfection.

A barrel link being fit with a small hand file. Imperfection here is measured in hundredths of an inch.

A completed STI TruBor, minus the C-more red dot sight and magwell. As close as you can come to perfection without breaking the law. Unless you live in California.

Next, we went through the Quality Assurance department, where problem guns are sent in by customers. These guys don’t deal with a lot of happy people, but (hopefully) when they’re done, a customer is happy once again. We didn’t spend a lot of time in here, but we did drop off a problem STI 2011 of mine. The magazines were hanging up, which we thought was the result of a cracked grip frame. It turns out the grip frame wasn’t cracked, but the magazine release tang was worn out. This error causes the magazine release to hang onto the magazine much tighter, making it a lot harder to release. The STI guys couldn’t fix it, so they gave me a new frame on the spot.

This pretty much wraps up my tour of the STI factory. Unfortunately, I didn’t get to see the injection molding process they use to make their grips. They were pretty busy, though, preparing for a visit from Ted Nugent the next day. Jay told us earlier that if we could fit it into our travel schedule, we could have come a day later to meet Ted. But, alas we couldn’t. Oh, well, in the words of Don Adams:

But, of course, Jay had to open the safe:

Every model of STI’s guns is in this safe, except the STI Sporting Rifle. Every one of these guns except the Texican (revolver, left side of the door, 2nd from bottom), the Spartan (I don’t know which, one of the many single stack 1911′s. Msrp for the Spartan is $698.00) and the GP6/GP6-c/GP5 (polymer double action/single action guns, on the rack at the bottom of the safe) are made at the STI plant in Georgetown, Texas.

Well, I had a blast at the STI factory, learned a lot, and got some free apparel! Thanks to STI, and especially to Jay Dunlap!

Jay and Me.