RoboFlail Front Frame Repair – Sheared Pivot Pin Replaced

A sheared pivot pin on a RoboFlail front frame can be repaired without replacing the frame. Simply Welding repaired the front frame of a RoboFlail remote-controlled tracked mower after its pivot pin sheared. We drilled out the broken pin, machined a stronger new one in our workshop, and welded it into the frame. The mower was back at work the next day.

Job Description

We removed the front frame from a RoboFlail remote-controlled all-terrain mower, removed what was left of the broken pivot pin, machined a new pin, then welded it in and refitted the frame.

Material Used

We used a medium carbon steel, which is stronger than mild steel and well suited to a pivot pin.

Removing the Old Pin

The broken pin was ground flush, the frame was set up on the milling machine and the rest of the pin was drilled out.

Machining the New Pin

A steel slug was set in the lathe, faced off at both ends to finished length, and the sharp edges were chamfered. The rest of the pin was turned on the lathe, then moved to the milling machine to drill two small holes for the retaining clips. We machined a larger radius where the smaller-diameter end meets the main body of the pin, to add strength at the exact point where the original had sheared.

Lining Up the New Pin

The new pin was set to factory dimensions (we hold these for most RoboFlail models), tack-welded into the frame, and the alignment was re-checked before full welding.

Fully Welding

The pin was fully welded with high-quality, European-made dual-shield wire. The frame was then wrapped in welding blankets and left to cool slowly over a couple of hours, which stops the weld area turning brittle and cracking later.

Final Prep

The frame was given three coats of etch primer and two coats of black topcoat, then refitted to the mower, tested and returned to the customer.

Result

The RoboFlail was back at work the next day, with a pivot pin stronger than the original at the point where it failed.

Frequently Asked Questions

Can a sheared RoboFlail pivot pin be repaired?

Yes. The remains of the broken pin can be drilled out and a new pin machined, welded in and lined up to factory dimensions, which we hold for most RoboFlail models.

Will the new pin shear again?

We machine a larger radius where the smaller-diameter end meets the main body of the pin. This adds strength at the exact point where the original pin sheared, so the repaired pin is stronger than the original at that point.

Why use medium carbon steel for a pivot pin?

Medium carbon steel is stronger than mild steel, which makes it well suited to a pivot pin that takes the load of the front frame.

Why was the frame wrapped in welding blankets?

Wrapping the frame in welding blankets made it cool slowly over a couple of hours. Slow cooling stops the weld area turning brittle and cracking later.

How quickly can you repair a RoboFlail?

It depends on the damage and our workload, but this RoboFlail was back at work the day after the repair.

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Broken pin, cracked frame or worn pivot on your RoboFlail or other machinery? Call 07747 682451 or send us some photos via WhatsApp.

Watch the repair: the new pivot pin machined on the lathe, the remains of the sheared pin drilled out of the RoboFlail front frame on the milling machine, and the new pin welded in.