Threading the anchor means self-securing, untying, threading and re-tying. Why the sequence is course material and what really matters in it.
Threading the anchor means: at the top you secure yourself, untie from the rope, thread the rope through the anchor and tie back in, without ever being unsecured in between. The goal is that your partner can lower you afterwards.
The honest answer: this is not a sequence to teach yourself from a text. For the DAV Kletterschein Outdoor, the DAV requires that you master the content of the Vorstieg (lead) certificate and the belay update, and it expects at least two and a half days of course with a maximum of six participants per leader [1]. Why so strict? During threading you are untied from the rope for a moment. That is exactly the connection whose failure led to serious falls in the gym statistics: in two reported cases the knot came undone when the climber sat into the rope at the anchor, with falls from about 10 and 14 metres [4, 5].
Outdoors there is more: The rock is not a maintained piece of sports equipment. As a rule there is no duty of care for the quality of the protection, so you are responsible for yourself [1]. This guide explains what the DAV teaches in the course and what matters, not how to try it on your own.
Entry criteria (common practice before you thread at the crag):
Before you start: is there an anchor, and does the rope reach the ground again when lowering? [1] The anchor is not climbed past. When you are up there, you clip it like a runner first if needed and then assess it [1].
Milestone: You answer both questions already from below, with topo and a view of the wall.
You clip the rope into the anchor point and secure yourself to the anchor with one or two quickdraws. Here the rule is: no "Stand" command, because your belayer keeps you in the rope [1].
Milestone: You are secured at the anchor before you release anything.
The rope is fixed to the belay loop of the harness (with a "Sackstich" knot and a carabiner) [1]. The DAV explicitly checks this as "redundancy through rope fixing in the belay loop" [1]. It is your net in case a single connection does not hold.
Milestone: You can show at any time at which two points you are secured.
Only now do you untie, thread the rope through the metal ring and tie back in [1]. The quickdraw-based self-belay is not unloaded meanwhile [1]. Practice: afterwards you check your new knot once more before you release the first protection.
Milestone: You thread near the ground under supervision until the order sits without questions.
First release the rope fixing at the belay loop, then call "Zu". Then release the self-belay and call "Ab" [1]. Lowering works as in the gym: commands, eye contact, slowly and evenly.
Milestone: Your instructor records all points as correct without any help.
The DAV calls the helmet a general recommendation for climbers and belayers: rockfall often cannot be ruled out, and in a fall there is a risk of head impact or collision with the belayer [1]. An evaluation of 2992 rock-climbing emergencies in Austria over 13 years agrees: the risk of severe or fatal injury rose when climbing without a helmet or without a rope [3]. In 138 of the 894 falls a belaying error came first [3].
This guide explains and motivates; it does not replace supervised training. You learn threading in a course with an instructor and a partner check at the crag, not from a text.
Make the decision before you start: thread or rappel? Metal ring at the anchor and the rope reaches the ground: thread. Tree or sling instead of a ring: rappel [1, 2]. The topo and the DAV's crag info help you clarify this already at the base of the wall [1].
Whoever decides only at the top decides in a hurry. Also agree with your belayer which commands you use up there before either of you starts [1].
Threading means passing the rope through the metal ring of the anchor after the lead so that you can be lowered. To do so you secure yourself, untie, thread the rope and tie back in [1]. This does not exist in the gym, it is outdoor material.
No. The DAV advises not to climb past anchors for safety and nature-conservation reasons [1]. In top rope, the climber's tie-in point always stays below the anchor [2].
You master the content of the Vorstieg certificate and the belay update. The course lasts at least two and a half days, the group has at most six people per leader, and children should take part from about age 13 [1].
The command "Stand" may only be used when the climber is to be taken out of the belay, for example when rappelling [1]. When threading you stay in your partner's belay system, which is why it is not used.
The DAV generally recommends a helmet for climbers and belayers. Whoever climbs without one must be able to rule out rockfall and dangerous falls [1]. The Austrian emergency evaluation found higher risks of severe injury without a helmet [3].
Top-Rope Climbing: Start Safely, Move Smoothly