Weight-Driven Skeleton Clock RE-120 with Graham Escapement

A weight-driven skeleton clock with a Graham deadbeat escapement and a 1-second pendulum. Every wheel, the winding click and the dial are printed; the clock runs on plain 3 mm steel rods.

• Going train, module 1 involute: great wheel 96 → pinion 8 → centre wheel 96 (1 turn per hour) → 8 → third wheel 80 → 8 → escape wheel 30 teeth (1 turn per 30 s)

• Motion work 12:1 (module 1.25): minute pinion 10 → 30 / 8 → hour wheel 32

• Graham anchor with circular locking faces centred on the pivot: zero recoil

• Pendulum 248 mm, period 1.0 s (2 beats per second)

• Winding click printed into the great wheel as a flexible arm: no spring to buy. Wind by turning the knurled drum flange backwards

• Hour hand rides on its own pipe, minute hand on a friction cannon so you can set the time

• Dial with raised Roman numerals: one-colour file, or ring + numerals as separate files for AMS

How it was checked

Designed in code (build123d). Every gear pair was rotated through a full tooth pitch in its real position without contact, with negative controls (0.3 mm closer or half a tooth out of phase must collide). The escapement was simulated by contact: 6.00° advance per beat, 0.000° recoil. All 24 parts were checked in the assembled position for interference, and the click was checked to lock in the driving direction and slip when winding. This is a new design and has not been test-printed and run yet: please post a make, and tell me how it runs.

What you need

• Printer with a 256 mm bed (A1, P1S, X1, MK4...): the plates are 140 × 182 mm and the pendulum prints diagonally

• 3 mm steel rod (silver steel / drill rod): arbors about 45 mm ×3, 50 mm (anchor), 65 mm (centre), 16 mm (minute wheel stud)

• 4 × M3 × 45 bolts + nuts for the pillars

• About 2 m of thin braided cord, and roughly 1 kg of nuts, steel shot or sand for the weight cup (170 cm³). Start light and add weight until it keeps running

Print settings

Sliced in Bambu Studio for the A1, 0.20 mm, PLA, no supports. Five plates, 3MF included: plate 1 front plate + small parts 1 h 18 min (28 g), plate 2 back plate + pillars + drum 1 h 12 min (32 g), plate 3 big wheels 1 h 21 min (28 g), plate 4 pendulum 17 min (10 g), plate 5 dial + weight cup 1 h 29 min (53 g). Total about 5 h 40 min and 151 g. Holes where an arbor turns are 3.5 mm; holes where a part is fixed to its arbor are 3.15 mm (press fit). Clean the escape wheel teeth and the anchor pallets carefully: they decide whether it runs.

About this design

Pictures are 3D renders of the CAD model, not photos. Makes and feedback welcome.

Español

Reloj de esqueleto de pesa con escape Graham de golpe muerto y péndulo de 1 segundo. Todas las ruedas, el trinquete de dar cuerda (un brazo flexible tallado en la rueda motriz, sin muelle) y la esfera se imprimen; los ejes son varilla de acero de 3 mm. Necesita una cama de 256 mm. Cinco placas, unas 5 h 40 min y 151 g. Diseño nuevo, aún sin imprimir: se agradecen makes.

العربية

ساعة هيكلية تعمل بالثقل مع ميزان غراهام وبندول ثانية واحدة. تطبع كل التروس والسقاطة والميناء، والمحاور قضبان فولاذ 3 مم. تصميم جديد لم يطبع بعد.