Cracked motor mounting plate

[Howard LewisParticipant @howardlewis46836]

Metal stitching works well on castings such cylinder blocks where there is metal all around (Such as water jackets )

It puts the parent metal into compression locally and tension further away.

In this instance the crack is open ended, so metal stitching might open it up and make the problem worse.

Ideal method would be to vee the crack on both sides, preheat and weld on both sides, followed by slow cooling (suggesting some form of insulation to reduce the rate of cooling and minimise stresses.

Too high a rate of cooling might cause a crack at the interface between the weld and the parent metal.

Failing welding, brazing might suffice, if the tensile strength is great enough (the crack must have been caused by subjecting the casting to a tensile load of some sort.. Again, for brazing preheating and slow cooling are requesites.

For mechanical means, as suggested several times either remake the complete motor plate from steel, welding the bosses onto plate, or bolt a steel plate to the casting, ensuring that there are fasteners on each side of the crack, so that any recurring tensile loads are taken by the steel plate.

This will probably need longer bolts to secure the motor, to take account of the extra thickness of the steel plate.

Howard.

Edited By Howard Lewis on 06/02/2021 13:50:27

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