ETA 901.001 Movement Winding Stem

Product Description

This is a genuine ETA 901.001 movement winding stem, an original Swiss-made component for the ETA 901.001 quartz movement. The stem connects the crown to the movement’s keyless works, enabling manual time setting and stem position control.

This brand new original part is essential for watchmakers restoring proper crown function when the original stem becomes worn, bent, or damaged. The replacement stem part number is ETA901001.405 with Tap 10 thread specification .

Key Features & Functions

• Designed for ETA 901.001 quartz movement
• Thread specification: Tap 10 (0.90mm)
• Part number: 401-1369 / ETA901001.405
• Enables manual time setting
• Essential keyless works component
• Swiss Made quality

About the ETA 901.001 Movement

The ETA 901.001 is a small quartz movement widely used in ladies’ watches. Key specifications include:

Usage Instructions

Function of the Winding Stem:

• The winding stem connects the crown to the movement’s keyless works

• When the crown is turned or pulled, the stem transmits these actions to the movement

• The stem has a Tap 10 thread (0.90mm diameter)

Crown Removal/Installation:
To remove the crown and stem from the ETA 901.001 movement:

1. Locate the arrow pointing to the detent button on the movement

2. Gently press the release button with a small screwdriver or fine tool

3. While pressing the button, gently pull the crown and stem out of the movement

Important Handling Tips:

• When reinstalling the stem, gently rotate the crown while pushing to ensure proper engagement

• Do not force the stem if resistance is felt – the release button may not be fully depressed

• Never use excessive force when pulling or pushing the crown

Installation Instructions

Tools Required:

• Case back opener

• Non-metallic tweezers

• Small screwdriver (for release button)

• Pin vise (for stem holding if crown needs removal)

Step-by-Step Installation:

Step 1: Prepare the New Stem

• Inspect the new genuine ETA stem for any defects or damage

• Clean the stem threads with Rodico to remove any debris

Step 2: Attach the Crown

• If reusing the original crown, screw it onto the new stem by hand, turning clockwise

• Ensure the crown’s internal threads match the Tap 10 specification

• Do not over-tighten – snug fit is sufficient

Step 3: Install the Stem

• Locate the release button on the movement (follow the arrow indicator)

• Press the release button with a small screwdriver

• Insert the new stem into the movement until it clicks into place

• Gently rotate the crown while pushing to ensure proper engagement

Step 4: Function Testing

• Test that the stem pulls out to the correct positions

• Ensure the crown turns smoothly in all positions

• Verify the hands move correctly when setting the time

Important Notes:

• The ETA 901.001 is a 2-hand movement (no seconds hand)

• The stem uses Tap 10 thread – ensure your crown matches this specification

• Professional installation is recommended for those without movement service experience

Repair Guide

Common Symptoms of Winding Stem Failure:

Diagnostic Process:

1. Visual Inspection: Under magnification, inspect the stem threads for wear, stripping, or damage. Check for any bending along the stem length.

2. Crown Check: Inspect the crown’s internal threads. If the crown threads are also stripped, both components should be replaced.

3. Movement Check: With the stem removed, inspect the keyless works for debris or damage.

When Replacement is Necessary:

• Visible thread damage or stripping on the stem

• Stem is bent or deformed

• The stem no longer engages properly with the setting mechanism

• The stem has snapped or broken

Preventive Maintenance:

• Avoid excessive force when setting the time

• Always pull the crown straight out – do not angle

• Have the watch serviced every 3-5 years

When to Seek Professional Help:

• The stem is broken and part remains inside the movement

• The keyless works show signs of damage

• You lack experience with movement disassembly

Frequently Asked Questions

Q1: What is the thread size of this winding stem?

A: The ETA 901.001 winding stem uses a Tap 10 thread, which corresponds to approximately 0.90mm thread diameter . This is a common threading specification for many ETA quartz movements.

Q2: Is this stem compatible with other ETA calibers?

A: According to parts suppliers, the ETA 901.001 winding stem (part 401-1369) is also compatible with ETA 901.005 . For other calibers, verify compatibility before purchasing.

Q3: Can I install this stem myself?

A: If you have experience with movement disassembly and the proper tools, installation is possible. However, stem replacement requires opening the case back and accessing the release mechanism. For users without experience, professional installation is recommended to avoid damaging the movement.

Q4: What are the hand sizes for the ETA 901.001 movement?

A: The ETA 901.001 is a 2-hand movement (hours and minutes only) with hand sizes of 1.20mm for the hour hand and 0.70mm for the minute hand . There is no seconds hand on this caliber.

Q5: How do I remove the crown and stem from the 901.001 movement?

A: Locate the arrow pointing to the detent button on the movement. Gently press the button with a small screwdriver while pulling the crown and stem out of the movement .

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