Star Trek's Self-Sealing Stem Bolts, Explained

In the "Star Trek: Deep Space Nine" episode "Progress" (May 9, 1993), Nog (Aron Eisenberg) and Jake (Cirroc Lofton) stumble upon a bizarre business opportunity. It seems that Nog's uncle Quark (Armin Shimerman) has accidentally purchased a large volume of yamok sauce, a condiment enjoyed mainly by Cardassians. Because there is only one Cardassian on Deep Space Nine, Quark has no use for the stuff. Nog asks his uncle if he and Jake can have it, and Quark agrees, happy to have it off his hands. 

Nog feels that he and Jake can sell the sauce, and they cleverly find a buyer. Sadly, the Lissepian freighter captain they speak to has no latinum with which to buy the sauce. The only thing he has is a gross of self-sealing stem bolts, which he offers in exchange. Knowing the sauce will soon spoil, and understanding there won't be too many other takers, Nog and Jake accept the offer. The gross of self-sealing stem bolts is loaded into one of the space station's cargo bays. But now a new conundrum has arisen: What are they going to do with all these stem bolts? Actually, they find that a more fundamental question needs to be asked first: What the heck is a self-sealing stem bolt? 

Eventually, Nog and Jake trade the bolts for several acres of land on the planet Bajor. Nog hates the idea, feeling that land is worthless; I guess there is no real estate market on Ferenginar. Luckily, their land gains value when the Bajoran government requires it for a construction project. To get their money, Nog and Jake sell their land to Quark for a tidy profit. Everything works out for them in the end.

About those stem bolts? Jake and Nog never did find out what they were used for.

The central joke of the episode is that neither Nog nor Jake — nor anyone else for that matter — knows exactly what a self-sealing stem bolt is. Only once they already have thousands of the buggers in DS9's cargo hold do they think to ask an engineer, Chief O'Brien (Colm Meaney), what a stem bolt is. O'Brien, however, is just as stumped. He doesn't know what a stem bolt does, what they're used for, or why anyone would want one. Only the name indicates that they can be used to bolt things down, and that it would be an advantage for a bolt to seal itself. 

A self-sealing stem bolt is, in brief, a useless widget. A vague thing with an unspecified technical function. The uselessness of stem bolts has become something of a running gag throughout "Star Trek," and the franchise's many writers have playfully kept their actual usage almost completely oblique. "Progress" was the last time anyone would see a self-sealing stem bolt on screen on "Deep Space Nine," but they were said to be useful on at least one other occasion. In the episode "Prophet Motive" (February 20, 1995), Quark would note that he also came into possession of a gross of self-sealing stem bolts on his own, and that he had found a legitimate buyer who would pay good money for them.

The buyer was going to offer Quark ten bars of gold-pressed latinum for the bolts, saying that they could more easily build multiple reverse-ratcheting routing planers with them. And what exactly is a reverse-ratcheting routing planer? Another widget whose function remains just as vague as a self-sealing stem bolt. The only thing we know about routing planers is that stem bolts are required in their manufacture.

In another wink to the widget, both a self-sealing stem bolt and a reverse-ratcheting router were once suggested as potential tools to stage a jailbreak in the "Deep Space Nine" episode "By Inferno's Light" (February 17, 1997), and O'Brien namechecked them again in the show's final episode, "What You Leave Behind" (June 2, 1999). O'Brien noted that engineers were invaluable to Starfleet officers who had graduated from Starfleet Academy, and that he was eager to take a new position as an instructor there. Someone, he said, had to teach Starfleet officers the differences between a flux capacitor and a self-sealing stem bolt.

It would take 21 years before another stem bolt showed up on "Star Trek," as they were mentioned in a third-season episode of "Star Trek: Discovery." Specifically, in the episode "Scavengers" (November 19, 2020). That season takes place after the U.S.S. Discovery had jumped forward in time over 900 years, and found that most of Starfleet had been wiped out in a galaxy-wide cataclysm. The cataclysm, called The Burn, caused all starships with dilithium crystals to explode, stymying most high-speed space travel. It was noted that the corpses of exploded starships had been cannibalized for parts, and that even their self-sealing stem bolts have been taken. 

The animated series "Star Trek: Lower Decks" was rife with references to old "Star Trek" episodes, so it was only a matter of time before that show's writers dropped in a reference to the bolts. It finally happened in the episode "Parth Ferengi's Heart Place" (October 5, 2023), an episode wherein Boimler (Jack Quaid) found a nervous Mariner (Tawny Newsome) tinkering with the featured widget in a fit of nerves. "You've been weathering that stem bolt so long," Boimler notes, "that it probably can't self-seal anymore." There is no note that Mariner is building a reverse-ratcheting routing planer, or anything else for that matter. 

Will the bolts return in future shows? Only time will tell.