Conical joints according DIN 12249, cone NS 12/21

Conical joints NS 12/21 are standardized ground-glass joint cores intended for modular laboratory glassware connections. Specified as Kern NS 12/21 and manufactured in accordance with DIN 12249, these conical joints follow the familiar nominal size system used throughout European laboratory practice, where the designation indicates the approximate large-end diameter and the length of the ground zone. The core geometry mates with matching NS 12/21 sockets, allowing apparatus to be assembled, disassembled and reconfigured without custom grinding. A single-piece pack size supports replacement of individual joints during maintenance or the build-up of small distillation, reaction or transfer setups. These conical joints from manufacturer Schlee belong to the general laboratory-material category and are suited to teaching laboratories, research benches and quality-control environments that rely on interchangeable NS glassware. Because the dimensions conform to DIN 12249, the joints integrate directly into existing inventories of conical ground joints, reducing the need for adapters and helping maintain consistent alignment in multi-neck flasks, condensers and receivers. The compact NS 12/21 format is a common choice for smaller-scale glass assemblies where reliable mechanical fit and chemical resistance of the ground surface are required.

This article is part of Distillation heads, adapters & columns, in Distillation & extraction glassware.

Key features

• Pack size: 1 pc
• Product type: Conical ground joint
• Joint size: NS 12/21
• Joint form: Core (Kern)
• Standard: DIN 12249
• Technical Information Sheet: