Some MSHA & OSHA rules make sense, like the
one about not leaving running machinery or equipment unattended, a
rule like many, born out of disaster.
You are lucky indeed! I can tell you stories of unattended
machines left running, where the outcomes were very expensive, and
some could have proved fatal.
Other Bill
On 9/1/2023 10:20 AM, Mark Kimball
wrote:
A few days ago I was cutting a small length of 1" square stock
with my bandsaw.? I supported the piece on a sacrificial strip of
aluminum to make sure it wouldn't tip down while being sawn.? The
sacrificial piece was a bit narrower than the stock so I could
grip it with the vise.? The mistake I made was to turn the saw on
and then I left for a "quick" errand.? But that turned into a much
longer interval -- so the saw was unattended.? Well, when I
finally came back the saw had stopped, but that's because the
cutoff piece had jammed the saw.? Probably because the sacrificial
piece prevented the saw from immediately turning off.? The scrap
got sucked into the bearing guides and jammed.
I didn't smell a burnt odor coming from the motor and the breaker
for that outlet had tripped so I was hopeful that the saw was OK,
but that turned out to not be the case.? With power restored and
the jam cleared, the motor clearly was dead.? My ohmmeter showed
an open connection.? It wasn't the switch which only left the
motor as the location of the open circuit.
I found that Harbor Freight claims to have replacement bandsaw
motors but they're about $150 so I thought it was worth my time to
see if I could fix the motor.? I found an online forum where
someone had repaired theirs by replacing a thermal cutout located
inside the motor housing so......maybe I might get lucky.
I removed the motor and took off the end nearest the power cord
connection but unfortunately my model had no thermal cutout.?
Still no bad burnt odor and the windings looked OK so I used my
ohmmeter some more to see if I could locate the open connection.?
I had to remove the heat-shrink tubing from the power
cord-to-windings connections and noticed that the hot and ground
return wires were stuck together.? More examination revealed that
they were melted.? ?They had been tied very tightly by some kind
of string so when the motor got hot enough to soften the
insulation the wires came in contact, blew out and tripped the
breaker.
Long story short, I replaced the power cord connections,
re-assembled the motor and tested it.? It ran with no noises,
tripped breakers or any obvious complaint.
I got lucky and learned a lesson.? Don't walk away from a running
bandsaw.
