I had to do some mods to a welding machine at work. Its a cobbled
together piece of crap but does the job, which is to weld an end cap
onto an inch and a half 18 ga tube. The cap is 4" in dia and sits into
a steel cup with a couple of small magnets to hold it in place while
assembling before welding. The cup was getting worn so I drew up
another one and sent it out for machining. Thinking that the original
magnets were a little wimpy, I upgraded them to a couple of 3/4" rare
earth ones. On receiving the cup and installing the magnets I though I
might have gone a little overboard as the end cap snap with a clang into
the cup. Undettered, I installed it in the machine and had the operator
run a part through. As he ran the first on there was an ungodly racket
from the weld as it rotated around, twice. A little puzzled, we though
maybe some contamination on the tubing caused the weld to screw up. So
we put in another part and the same thing happened. Looking closer at
the results, the weld problems were over the magnets, I then clued in
that the super magnets were blowing out the arc as it passed over them.
I took it back, removed the magnets and had new holes installed
father out and much smaller (3/8") Works much better now :-) They say
the best way to learn is from ones mistakes, then I must be a bloody
genius :-)
James Crombie
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