Kinshofer KM602 Severed Ram Lug Repair – Welded and Strengthened With Gussets

A severed or cracked ram lug on a Kinshofer KM602 clamshell grab bucket can be welded back into position and strengthened with gussets, rather than replacing the bucket. Simply Welding repaired a Kinshofer KM602-500lt clamshell bucket after its ram lug was severed. On this bucket, the 40mm ram clevis-to-clam pivot lug had almost completely sheared off. We repaired and strengthened it, and supplied a Kinshofer loan bucket, so the customer's machine was only down for 2 hours.

Job Description

We repaired a severed ram lug on a Kinshofer KM602-500lt clamshell bucket and strengthened it to stop it happening again.

Materials Used

Welding consumables, oxy-propane and 12mm steel plate for the extra gussets.

Cause of the Damage

The bucket had been grabbing broken-out reinforced concrete. The steel reinforcing bar hadn’t been cut, so the concrete jammed in the bucket and put huge stress on the lug.

Inspection and Prep

The hydraulic cylinder was removed and the damage was inspected. The lug had pulled away from the cross tube and bent backwards. The remaining weld was arc-gouged out, then the lug and tube were cleaned and bevelled ready for welding.

Preheating and Welding

The lug was heated, eased back into position and tack-welded, and the alignment was checked by measurement. The cross tube and lug were then preheated to a set temperature and fully welded.

Strengthening With Gussets

Gussets cut from 12mm steel plate were welded into the high-stress areas. We also welded gussets into the opposite side of the bucket to prevent the same failure there in future.

Assembly, Testing and Refitting

The bucket was reassembled, tested and refitted to the customer’s machine.

Loan Bucket

We supplied the customer with a Kinshofer loan bucket while the repair was carried out.

Result

The customer’s machine was down for just 2 hours, instead of standing for more than 2 days waiting on the repair.

Frequently Asked Questions

Why do grab bucket ram lugs crack or break?

A common cause is grabbing material that jams in the bucket. In this case, broken-out reinforced concrete with uncut steel reinforcing bar jammed the clamshell and put huge stress on the ram lug until it sheared away from the cross tube.

Can a severed grab bucket lug be repaired?

Yes. The lug can be heated and eased back into position, welded to the cross tube, then strengthened with gussets in the high-stress areas so it's stronger than before.

Do you supply loan buckets during repairs?

Yes. We can supply a Kinshofer loan bucket while your grab bucket is repaired, keeping your machine working and downtime to a minimum.

Will the lug on the other side fail too?

It can, as both sides take the same load. On this bucket we welded gussets into the opposite side as well, to prevent the same failure there in future.

How can I stop my grab bucket lugs breaking?

Avoid grabbing material that can jam in the bucket. On this job the damage was caused by broken-out reinforced concrete where the steel reinforcing bar hadn't been cut.

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Cracked or severed lug on your grab bucket? Loan buckets available. Call 07747 682451 or send us some photos via WhatsApp.