Cracked motor mounting plate

It might be just as easy to make up a new plate in mild steel and - while you at at it - make the attachment hole with support on both sides, not just in the middle. This is the same device that had a bent Whitworth screw, about a fortnight ago, isn't it?

Cheers, Tim

It is the same piece. My difficulty at the moment is that whilst I have the individual small pieces at home, the bulk of the saw is in a friend's warehouse some 20+ km away, so it's difficult to look at them together to see how best to modify them.

I'm still trying to get a nut or bolt 1/2" BSW to make sure that the size is correct. Brexit now means that £25 worth of filament costs me an extra €30+ to import. It is no longer economical to buy anything from the UK. This is a great shame because I find it much easier to source what I need in the UK and better understand the different brands available.

Your best bet would be to find someone who can stitch the crack together using the metal lock method. This will give a repair that will be far stronger than welding and it will reduce any chance of further stress cracking caused by welding. It could be welded or brazed but a lot of care must be taken with preheating , peening and then the part must be allowed to cool very slowly in an oven . Metal stitching will avoid all the problems mentioned .

You could do worse than get your filament from Prusa in the Czech Republic, expensive but the ones I have tried have all been very good. Now of course suffering , as you, from Brexit effects but the other way round, so to speak.

Amazon Basic filaments are not too bad, I think Amazon might have a small warehouse somewhere in the EU

John

Edited By Journeyman on 06/02/2021 13:49:19

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