For quick coupler matching, the most important dimensions are pin diameter, arm width, center distance and bucket ear width. Clear photos and a simple sketch help avoid wrong bracket matching.
Quick Coupler Measurement Points
Measure the key dimensions before ordering a quick coupler. A simple drawing with clear photos helps reduce wrong matching risk.
Key Measurement Factors
Measure the pin or pin hole diameter in millimeters with a caliper.
Measure the inside width of the excavator arm, not the outside width.
Measure from the center of one pin hole to the center of the other pin hole.
Confirm the ear spacing on the bucket or attachment side.
Machine plate photos help confirm standard dimensions when drawings are unavailable.
Manual, hydraulic, tilting and rotating couplers use different structures.
Why Accurate Coupler Measurement Matters
Wrong pin size or arm width can cause installation failure, excessive clearance, unsafe locking or delivery delays. Even when the excavator model is known, previous repairs, non-standard buckets or regional machine variants can change dimensions. Accurate measurements reduce rework and help KRATOR prepare a coupler that fits the carrier and attachments.
How to Measure Pin Diameter
Use a caliper to measure the existing pin diameter or the pin hole diameter. Record the value in millimeters. If the pin is worn, measure several points and send photos so the technical team can judge the correct nominal size.
How to Measure Arm Width
Measure the inside width between the excavator arm plates. Do not measure the outside width. The coupler must fit between the arm plates with correct clearance, so this dimension is critical for bracket machining.
How to Measure Center Distance
Measure the distance from the center of the front pin hole to the center of the rear pin hole. A simple drawing with A, B, C and D dimensions is enough if photos are also provided.
Photos Buyers Should Send
Send the machine plate, arm side view, linkage photo, bucket ear photo, existing pin photo and a simple sketch with dimensions. These images help confirm whether the coupler should match the arm, bucket or both.
Final Check Before Ordering
Before confirming the order, check excavator model, operating weight, pin diameter, arm width, center distance, bucket ear width, hydraulic line requirement and whether the coupler must fit multiple buckets.
Quick Coupler Measurement Table
| Item | What to Check | Why It Matters |
|---|---|---|
| A | Pin diameter | Measure pin or pin hole diameter in mm |
| B | Arm width | Inside width between arm plates |
| C | Center distance | Center to center distance of two pin holes |
| D | Bucket ear width | Attachment ear spacing for bucket compatibility |
Common Mistakes
- Measuring outside arm width instead of inside width.
- Sending photos without any scale or dimension marks.
- Forgetting that different buckets may have different ear spacing.
- Assuming one regional excavator model always has identical pin data.
What Information to Send for Quote
- Excavator brand and model
- Operating weight
- Pin diameter
- Arm width
- Center distance
- Bucket ear width and photos
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