Automatic Goldbeating Hammer Driven by Geared Wheels

Trip-hammer worked by wheels K and X and drum S

This is described as the greatest blow the goldbeater can use. The wheel K lifts the hammer o by the tooth m through the lever n; the hammer pauses an almost indivisible instant on the support l, then the tooth h of the drum S catches the tooth f and drives the hammer down onto the anvil g, whereupon the next tooth of K raises it again. The middle of the hammer should not pass beyond the point c.

Wooden rest l used as a rebound spring

Although a note below says to remove the wood l, Leonardo judges it more useful to keep it and let it act as a spring. When the hammer o strikes the wood l, the spring yields and then, springing back, gives the hammer a contrary motion. So when tooth h meets tooth f the hammer falls with great ease, its descent already begun by the rebound.

Gear ratios of the driving train

The hammer's speed is multiplied through the gear train, whose ratios are recorded. The wheel of the first motion carries 128 teeth driving an 8-spindle drum, the wheel K has 8 teeth, the wheel X 64 teeth, and its drum S 8 spindles. The labels S 8, X 64, K 8 and the counts 128 and 8 mark these tooth and spindle numbers on the drawing.

Beating the gold for width

A short middle caption observes that in one case the gold, not the hammer, must be moved. That is when the gold is beaten for width rather than struck flat in place.

Figura grande comprendente numeri e lettere: In alto, a sinistra del martello:

In alto, a destra del martello:

Sotto la colonna di testo in alto a destra figura:

A sinistra dell'incudine, figura con le lettere:

Sotto, rocca con lettera e numero (di fusi):

Sotto la rocca, ruota con lettera e numero (di denti):

A sinistra altra ruota con lettera e numero (di denti):

Più a sinistra, lungo la piega del foglio, rocca con il numero (di fusi):

Poco sotto, fusi e ruota con il numero (di denti):

Nell'angolo in alto a destra, la didascalia:

Più in basso, la didascalia:

Sotto la figura, nella metà inferiore del foglio, la didascalia:

Large figure with numbers and letters. Above, to the left of the hammer:

Above, to the right of the hammer:

Beneath the column of text at upper right, figure:

Left of the anvil, figure with the letters:

Below, a drum with letter and number (of spindles):

Below the drum, a wheel with letter and number (of teeth):

To the left, another wheel with letter and number (of teeth):

Further left, along the fold of the sheet, a drum with the number (of spindles):

A little below, spindles and wheel with the number (of teeth):

In the upper right corner, the caption:

Lower down, the caption:

Below the figure, in the lower half of the sheet, the caption:

Automatic Goldbeating Hammer Driven by Geared Wheels

On this page

Trip-hammer worked by wheels K and X and drum S

Wooden rest l used as a rebound spring

Gear ratios of the driving train

Beating the gold for width