Lenz - The Specialist for Ground Joints

The Lenz® range of ground joint instruments
With decades of experience, advanced technological know-how and the outstanding
properties of DURAN® glass we guarantee the proven quality of our
precision ground joints.

The Lenz® range of ground joint instruments includes conical joints, stopcocks,
ground joint flasks, separating and dropping funnels as well as a large range
of ground joint components.

Quality with system
Lenz® ground joint instruments are produced according to the standard
DIN 12242 / ISO 393. Each production step is tested by a quality management
system, based on DIN ISO 9001 / EN 29001. The tests are examined by a cone
measuring device for checking the taper, a surface roughness meter for testing
the roughness parameters and a wall thickness measuring apparatus with a
magnetic inductive measuring process to guarantee a homogenuos concentricity
and wall thickness.

A multiple-station unit serves for grinding as well as for pre- and post-polishing
of our ground joints. An electro-mechanical scanner ensures constant quality.
In cases of specific high demands on function and precision the grinding
is processed by hand.


Production of ground joint workpieces made of DURAN® tubing on fully automatic glass forming machines.	The follow-up processing of NS cones on half-automatic circular grinding machines.	The pre- and post-polishing of NS sockets takes place on multiple station grindig machines.	Conicity testing: the accuracy of the ground joints is validated by highprecise cone measuring devices.

Product features
• High taper accuracy of the cones
• Precise concentricity
• Small roughness of the surface
• Excellent tightness
• Minimized need for grease
• No bend out of line

Our ground joint instruments are marked
with the Lenz logo and indicate the
respective size of the ground joint.

Conical ground joints
acc. to DIN 12242/ISO 383

Nominal size (NS)	Cone/socket* Ø1 (mm)	Cone/socket* Ø2 (mm)	Length (mm)
5/13	5	3,6	13
7/16	7,5	5,8	16
10/19	10	8	19
12/21	12,5	10,3	21
14/23	14,5	12,1	23
19/26	18,8	16,1	26
24/29	24	21	29
29/32	29,2	25,9	32
34/35	34,5	30,9	35
45/40	45	40,9	40
60/46	60	55,3	46
71/51	71	65,8	51
85/55	85	79,4	55
*approximate measures