diff --git a/crates/fj-kernel/src/builder/edge.rs b/crates/fj-kernel/src/builder/edge.rs
index f85b1bc45..ba5f3369a 100644
--- a/crates/fj-kernel/src/builder/edge.rs
+++ b/crates/fj-kernel/src/builder/edge.rs
@@ -6,7 +6,7 @@ use crate::{
         Curve, GlobalVertex, Objects, Surface, SurfaceVertex, Vertex,
         VerticesInNormalizedOrder,
     },
-    partial::{HasPartial, PartialGlobalEdge, PartialHalfEdge},
+    partial::{HasPartial, MaybePartial, PartialGlobalEdge, PartialHalfEdge},
     storage::Handle,
     validate::ValidationError,
 };
@@ -15,6 +15,12 @@ use super::{CurveBuilder, GlobalVertexBuilder};
 
 /// Builder API for [`PartialHalfEdge`]
 pub trait HalfEdgeBuilder: Sized {
+    /// Update the partial half-edge with the given back vertex
+    fn with_back_vertex(self, back: impl Into<MaybePartial<Vertex>>) -> Self;
+
+    /// Update the partial half-edge with the given front vertex
+    fn with_front_vertex(self, front: impl Into<MaybePartial<Vertex>>) -> Self;
+
     /// Update partial half-edge as a circle, from the given radius
     ///
     /// # Implementation Note
@@ -40,6 +46,16 @@ pub trait HalfEdgeBuilder: Sized {
 }
 
 impl HalfEdgeBuilder for PartialHalfEdge {
+    fn with_back_vertex(self, back: impl Into<MaybePartial<Vertex>>) -> Self {
+        let [_, front] = self.vertices();
+        self.with_vertices([back.into(), front])
+    }
+
+    fn with_front_vertex(self, front: impl Into<MaybePartial<Vertex>>) -> Self {
+        let [back, _] = self.vertices();
+        self.with_vertices([back, front.into()])
+    }
+
     fn update_as_circle_from_radius(
         self,
         radius: impl Into<Scalar>,
diff --git a/crates/fj-kernel/src/partial/objects/cycle.rs b/crates/fj-kernel/src/partial/objects/cycle.rs
index bc8479abf..461c48fdb 100644
--- a/crates/fj-kernel/src/partial/objects/cycle.rs
+++ b/crates/fj-kernel/src/partial/objects/cycle.rs
@@ -1,4 +1,5 @@
 use crate::{
+    builder::HalfEdgeBuilder,
     objects::{Cycle, HalfEdge, Objects, Surface},
     partial::{
         util::merge_options, MaybePartial, PartialHalfEdge, PartialVertex,
diff --git a/crates/fj-kernel/src/partial/objects/edge.rs b/crates/fj-kernel/src/partial/objects/edge.rs
index 7b5ffe3c9..fb8d268ad 100644
--- a/crates/fj-kernel/src/partial/objects/edge.rs
+++ b/crates/fj-kernel/src/partial/objects/edge.rs
@@ -73,28 +73,6 @@ impl PartialHalfEdge {
         self
     }
 
-    /// Update the partial half-edge with the given back vertex
-    pub fn with_back_vertex(
-        mut self,
-        vertex: impl Into<MaybePartial<Vertex>>,
-    ) -> Self {
-        let [from, _] = &mut self.vertices;
-        *from = vertex.into();
-
-        self
-    }
-
-    /// Update the partial half-edge with the given front vertex
-    pub fn with_front_vertex(
-        mut self,
-        vertex: impl Into<MaybePartial<Vertex>>,
-    ) -> Self {
-        let [_, to] = &mut self.vertices;
-        *to = vertex.into();
-
-        self
-    }
-
     /// Update the partial half-edge with the given vertices
     pub fn with_vertices(
         mut self,