# Internally threaded or threadless? The choice nobody explains, because both answers are correct
July 2026 · Body Art News · Poli International
There is a well-worn article on this site about internal versus external threading, and the internet is full of others. They all reach the same verdict, and the verdict is right: a screw thread should never be dragged through a healing wound.
What almost nobody writes is what happens after you accept that. You are left with more than one option, and they are not variations on a theme. They hold together by different physics.
This article compares the two you will meet most often in a metal studio: internally threaded and threadless. There is a third, push-fit, which holds by a tapered interference fit rather than by a thread or a bent pin, and which is covered separately. Be careful with the names: much of the industry, including NeoMetal, uses "push-fit" and "press-fit" as loose synonyms for threadless, even though the retention mechanisms are not the same.
» The professional standard permits both. The Association of Professional Piercers describes internally threaded jewellery as having a smooth post with "the threads on the removable end(s)", and threadless as jewellery that "uses a pin coupling on the ornamental end, and there are no screw threads at all" [1].
» Threadless is not new and not generic. It was invented by NeoMetal in 1997, and the company makes it in implant certified titanium to ASTM F-136 [2].
» Threadless retention is set by hand. The pin is inserted about one third of the way into the shaft and bent between 10 and 20 degrees; bend it further for a tighter fit [3].
» Internal threading is a machining problem. Anatometal describes it as requiring "precise machining to ensure a threaded hole is placed within the barbell end without compromising its durability, regardless of the gauge" [4].
The distinction that actually matters
An internally threaded connection is a fixed mechanical fit. The thread was cut at the factory, to one pitch, and it is either engaged or it is not. Nothing about it changes between the day it was machined and the day you take it out.
A threadless connection is a tension fit, and the tension is a variable somebody chooses. NeoMetal's own instructions are explicit that the bend angle *is* the retention setting: insert the pin roughly a third of the way, bend it 10 to 20 degrees, and bend it further if you want it tighter [3].
Read those two sentences next to each other and the trade-off stops being a matter of taste. One system arrives finished. The other arrives adjustable, and someone has to adjust it.
What each one is good at
Threadless cannot be cross-threaded or stripped
There is no thread, so the entire category of thread failure disappears. You cannot cross-thread a pin. You cannot strip a socket by over-tightening it. For a piece that gets opened and closed often, that matters more than it sounds, because a stripped internal thread does not announce itself before the end goes missing.
Threadless retention is tunable to the piercing
Because the bend sets the tension, the same components can be set loose enough to change easily or firm enough to survive a jumper being pulled over your head. That is a real advantage on anatomy where the two requirements pull in opposite directions.
It also cuts the other way. A pin bent too little can back out. NeoMetal's guidance for curved and circular pieces is noticeably more involved than for a straight post, calling for a reverse bend against the curve, or an S-shaped bend, with an explicit warning to "avoid over bending" on the smaller circular barbells [3]. This is a skill, not a click.
Internal threading is unambiguous once it is home
A thread that is done up is done up. There is no judgement call about whether the retention is sufficient, no setting that can drift, and nobody has to have understood a bending diagram. For a piece you intend to leave alone for months, that is a genuine virtue.
The cost is in the manufacturing, and it is not trivial. Cutting a threaded hole into a component while leaving enough wall thickness for it to survive is the hard part of the job, and Anatometal names durability as the constraint [4]. This is why quality separates so visibly at small gauges, and why cheap jewellery so often puts the thread on the outside instead: external threading is simply easier to make.
The compatibility trap
This is the part that costs people ends, and it applies to both systems.
Threaded body jewellery has no single industry-wide pitch. Pieces from one manufacturer may not fit another's, even at the same gauge. Threadless has its own version of the same problem: "universal" is a claim that holds within a curated range of components, not across the entire market.
The practical rule is the same either way. Keep a piece within the system it came from, and treat a replacement end from a different maker as something to be tried before it is relied on, not assumed.
Which one should you actually be wearing
For an initial piercing, either meets the standard, so the deciding factors are the ones nobody puts in a comparison table.
Choose threadless if the jewellery will be changed often, if you like the idea of retention that can be tuned, and if your piercer is fitting it. Choose internally threaded if the piece is going in to stay, if it will live under clothing or a helmet, or if you would rather have a connection that does not depend on anyone's judgement about a bend angle.
What should not decide it is price. Both systems, made properly, are made from the same implant certified titanium [1] [2], and a cheap example of either is a worse choice than a good example of the other.
FAQ: the questions that follow
Is threadless weaker than threaded?
No, but it fails differently. A thread holds by mechanical engagement; a threadless pin holds by tension, and that tension is a setting: about one third of the pin inserted, bent 10 to 20 degrees, more bend for a tighter fit [3]. A correctly set pin is secure. An under-bent one is a failure mode threaded jewellery simply does not have.
Can I use another brand's end on my post?
Treat it as something to test, never something to assume. Threaded body jewellery has no single industry-wide pitch, and threadless "universal" fit describes a curated range of components rather than the whole market. Losing an end in a sink usually costs more than buying the matching one.
Which is easier to change myself?
Threadless, in principle, because there is nothing to cross-thread. In practice it depends on the piercing. A straight labret post is straightforward, while curved and circular pieces need a reverse or S-shaped bend, with an explicit warning against over-bending on the smaller circular sizes [3].
Is externally threaded jewellery ever acceptable?
Not for the surface that passes through you. The standard exists because an externally threaded post has "the screw pattern cut into the post, and this comparatively rough surface may be passed through the tissue to insert and remove the jewelry" [1]. That is precisely what both systems on this page were designed to avoid.
Patrick's note
I have spent a lot of years on the manufacturing side of this, and the thing I would want a reader to take away is that these are not two styles. They are two different engineering answers to the same problem, and each one moves the difficulty somewhere else.
Internal threading moves it into the factory. Getting a clean, durable thread into a small component is a machining problem, and it is solved once, by the manufacturer, for every piece that leaves the building.
Threadless moves it to the counter. The parts are simpler, but the retention is not finished until a person sets it, which is why NeoMetal publishes a bending guide at all. That is not a flaw. It is a design that trades factory precision for fitted adjustability, and it works extremely well when the person doing the fitting knows what they are doing.
That is the honest answer to a question the industry mostly skips: the better system is the one whose failure mode you are best placed to avoid.
