Unitas 521 – interchangeable spare parts

Unitas (UT) 521 movement

Which spare parts fit the Unitas 521 movement? For every part you can see which other calibers use the same part according to the original interchangeability list.

30Parts with interchange data

36Calibers sharing parts

Note: We have compiled this overview to the best of our knowledge and belief, based on the original interchangeability lists of Unitas (UT) and the original spare-part labels. All information has been carefully checked but is provided without guarantee. Please verify the interchangeability yourself before fitting, especially the height, diameter and execution of the part.

🔧 Interchangeable parts

Part no.	Description	Also fits
182ISO 20.030	Barrel and cover	Unitas 510 Unitas 520
195ISO 20.060	Barrel arbor	Unitas 510 Unitas 520
201ISO 30.015	Center wheel	Unitas 520
210ISO 30.025	Third wheel	Unitas 520
220ISO 30.027	Fourth wheel	Unitas 520
240ISO 31.080	Cannon-pinion	Unitas 510 Unitas 520 Height 190 Unitas 510 Unitas 520 Height 210 Unitas 510 Unitas 520 Height 240 Unitas 510 Unitas 520 Height 270 Unitas 510 Unitas 520 Height 300 Unitas 510 Unitas 520 Height 340 Unitas 510 Unitas 520 Height 420 Unitas 510 Unitas 520 Height 470 Unitas 510 Unitas 520
250ISO 31.046	Hour wheel	Unitas 510 Unitas 520 Height 100 Unitas 510 Unitas 520 Height 120 Unitas 510 Unitas 520 Height 150 Unitas 510 Unitas 520 Height 180 Unitas 510 Unitas 520 Height 210 Unitas 510 Unitas 520 Height 250 Unitas 510 Unitas 520 Height 330 Unitas 510 Unitas 520 Height 380 Unitas 510 Unitas 520
260ISO 31.041	Minute wheel	Unitas 510 Unitas 520
301ISO 40.301	Regulator for flat hairspring	Unitas 510 Unitas 520
311ISO 70.800	Upper cap jewel with end-piece	Unitas 180 Unitas 187 Unitas 199 Unitas 510 Unitas 520 Unitas 560 Unitas 570
330ISO 70.801	Lower cap jewel with end-piece	Unitas 190 Unitas 510 Unitas 520
336ISO 70.806	Upper cap-jewel with end-piece, for escape wheel	1st execution Unitas 520 2nd execution Unitas 180 Unitas 187 Unitas 190 Unitas 200 Unitas 200N Unitas 201 Unitas 201N Unitas 510 Unitas 520 Unitas 630 Unitas 6360 Unitas 6365 Unitas 6470 Unitas 6475 Unitas 6476 Unitas 6480 Unitas 6485 Unitas 6486
346ISO 70.807	Lower cap jewel with end-piece, f. esc. wheel	Unitas 190 Unitas 200 Unitas 200N Unitas 201 Unitas 201N Unitas 510 Unitas 520 Unitas 630 1st execution Unitas 176 Unitas 190 Unitas 200 Unitas 200N Unitas 201 Unitas 201N Unitas 231 Unitas 233 Unitas 234 Unitas 285 Unitas 286 Unitas 343 Unitas 429 Unitas 431 Unitas 432 Unitas 510 Unitas 520 Unitas 630
401ISO 51.010	Winding stem	Unitas 510 Unitas 520
407ISO 31.121	Clutch wheel	Unitas 510 Unitas 520
410ISO 31.120	Winding pinion	Unitas 510 Unitas 520
422ISO 81.067	Crown wheel ring	Unitas 190 Unitas 510 Unitas 520 Unitas 540 Unitas 550 Unitas 580
423ISO 81.136	Crown wheel core	Unitas 520
425ISO 51.120	Click	Unitas 190 Unitas 510 Unitas 520
430ISO 61.080	Click spring	Unitas 190 Unitas 510 Unitas 520
435ISO 51.050	Yoke	Unitas 510 Unitas 520
440ISO 61.100	Yoke spring	Unitas 510 Unitas 520
443ISO 51.080	Setting lever	Unitas 510 Unitas 520 2e
443/5443ISO 51.080.06/.01	Setting lever	Unitas 510 Unitas 520 2e
445ISO 51.090	Setting lever spring	Unitas 510 Unitas 520 2e
450ISO 31.100	Setting wheel	Unitas 510 Unitas 520
702ISO 30.040.12	Escape wheel and pinion, pivoted, for two end-pieces	Unitas 520
704ISO 30.040.10	Escape wheel and pinion, for upper end-piece	Unitas 520
705ISO 30.040	Escape wheel and pinion	Unitas 520
710ISO 40.010	Jewelled pallet fork and stat	AV 41 Felsa 302 Unitas 510 Unitas 520

Source: original interchangeability lists of Unitas (UT) (checked transcription) and checked original spare-part labels · as of 2026-10-28. Height / execution: the part fits only in this height or execution.

🌀 Matching mainspring

Mainspring dimensions for Unitas 521 (height × diameter × thickness × length) and matching mainspring in our shop:

Unitas 520 à 524: 1.50 × 7.5 × 0.08 × 260 mm (GR 4077) · 🛒 1

🔗 Movements sharing the most parts

→ All calibers of Unitas (UT)

❓ Frequently asked questions

Which Unitas 521 spare parts also fit other movements?

For the Unitas 521, 30 part numbers are listed as interchangeable. Together they fit 36 other calibers – the table below shows which part fits which movement.

Which movements share the most parts with the Unitas 521?

The most shared parts: Unitas 520 (48 parts), Unitas 510 (40 parts), Unitas 190 (7 parts).

Which mainspring fits the Unitas 521?

According to the Générale Ressorts catalogue (height × diameter × thickness × length): 1.50 × 7.5 × 0.08 × 260 mm (GR 4077, hand-wound, normal end hook).