“The Clavulus and the bridge of the glasses.” Discover lesson 5 of the master Sandro Gonnella

lesson N°5

The Clavulus

The Clavulus is a machine formed by a mould and by a steel counter mould that press onto each other, compressing the frame in the desired point. The operation appears simple, but in reality requires precision and accuracy. First, Sandro recommends heating the glasses with a ventilated heater so as to make the frame malleable and the risk of breaking the acetate is avoided.

Acetate is a material that, once heated, is very flexible, but, when it cools, it remains in the position it was given.

Heating the eyewear repeatedly and applying the right force in the central point of the frame, the peculiar hump of each pair of glasses is created. Here, too, it is best to proceed in small steps in order to maintain perfect control over the final result.

Endpieces and temples

Ingenuity is a key quality of every master craftsman. Sandro not only constructs modern one-of-a kind glasses, but strives to create new, functional tools to help him in his work. An example of these is the tool he used to insert the endpieces in the frame and the temples: a modified welder that heats the endpieces quickly, so that they can easily be "drowned" in the acetate. The metal the endpieces are made of, in fact, reaches a high temperature quickly in contact with the welder, and when they come into contact with the surface of the acetate, they melt it and can be inserted with simple pressure.

Once the endpieces have been inserted, any excess parts are removed with a cutter and the job is finished with a file. It is essential not to scratch the rest of the frame, proceeding with precise and secure gestures.

Scarica il memorandum della lezione


The tailored eyewear course

In 6 lessons Sandro Gonnella will illustrate how a dialogue with the customer, various inspirations and technology can give rise to a true masterpiece "Made in Italy." All the secrets and tips for talented young people from the most appreciated "eyeglass tailor" in the world.

Find out more

check out
the programme

the programme

  • 30_09_2014 30_09_2014
  • 07_10_2014 07_10_2014
  • 14_10_2014 14_10_2014
  • 21_10_2014 21_10_2014
  • 28_10_2014 28_10_2014
  • 04_11_2014 04_11_2014

Lesson n° 1

Knowing your customer means being able to design the perfect eyewear. How to establish a genuine relationship and intuitively use small details to choose the features of the finished eyewear.

Watch the lesson

Lesson n° 2

Designing a tailor-made frame. How to take inspiration from art, architecture and the local territory and then imagine the perfect pair of glasses for each customer. Creative interaction with the client.

Watch the lesson

Lesson n° 3

From the design to the pantograph. Cutting the nose pads, the lens and the rim: the primordial frame takes shape. Feedback and interaction with the customer.

Watch the lesson

Lesson n° 4

Having obtained a basic model with the pantograph, now all sharp edges and the excess material left by the first mechanical cutting must be removed skilfully by hand.

Watch the lesson

Lesson n° 5

How to obtain the characteristic curve of the bridge of the glasses by using the Clavulus. In addition, how to choose and manually apply the perfect endpieces for any type of temple.

Lesson n° 6

Once the tumbling has been completed in a specialised laboratory, it is time to apply the "signature" that a young outstanding craftsman Made in Italy should use to take his place in the world. To conclude the customer experience, a suitable handmade case must be chosen and all the elements in detail must be given a final cleaning.

Watch the lesson

Add a reminder

Sandro Gonnella

Add reminders to your diary. Make sure you won’t miss even one Maestro lesson!
You’ll receive a memo today and another one when the lesson is published on the platform.


Add a reminder

The reminder has been added!
You will receive an email on the day of the event, with a link to join in.


Add a reminder

You have already added the remainder!
You will receive an email on the day of the event, with a link to join in.