Dead mill

[Sshire]

So there I was. Milling another part for Elmer's Grasshopper and the BF20 mill started, stopped, started, stopped. :-\
That's it. Stopped. Fuse fine. Unplugged and replugged every connector in the control box. Used my patented, "smack the part with my hand" technique. Nothing. The RPM indicator is lit and shows 0 RPM. Motor not turning.
I'll call PrecisionMatthews in the morning. Unless someone has an idea, I'll start on part I can make on the lathe.
At least I can look at my new Bison 5C Set Tru chuck until its faceplate arrives ;D
Bummer

Stan

 

[Jasonb]

Have a look at teh brushes

J

 

[Tin Falcon]

I would start troubleshooting with a multimeter see where the power is not getting through could be the motor could be the power supply/ Pusle width modulator. sounds like you ruled out a loose connection could be something as simple as a broken wire or bad connector. IIRC that is under warranty so would not go any further than part level troubleshooting. Sometimes something simple.
Tin

 

[Sshire]

IT'S ALIVE!!!
Jasonb gets the prize. Thank you, thank you.
I pulled the motor cover and was going take Tin's suggestion to get out the multimeter and start checking voltages, etc. when I remembered Jason's post. Took out brush #1. Slipped out very smoothly and was clean and shiny. Brush #2 was stuck. VERY gentle pulling and wiggling followed. Finally popped loose. The brush was very dull looking. 600 grit around a 0.25 dowel and got it clean and shiny. Replaced brush. Fingers crossed. IT WORKED!!! Christmas miracle.
Thanks for all the suggestions. Having a very limited knowledge of motors, can someone explain what caused one brush to get stuck and dull looking? Is it something I did?
Anyway, we now return you to your regularly scheduled milling.
Best
Stan

 

[Jasonb]

Can't tell you why apart maybe from poor fit to start with. Had a similar problem with my lathe where one brush had worn more than teh other, got hot and softened the spring.

 

[Springbok]

Looking at the r/h brush I think it would be worthwhile ordering a new set

Bob

 

[Jasonb]

I did better than that, ordered a new set and another as a spare you know that if they fail again it will be just at the wrong time.

J

 

[Ken I]

can someone explain what caused one brush to get stuck and dull looking? Is it something I did?

Almost certainly nothing that you did - sometimes a small fragment chips off and wedges the brush - other times its simply build up of dust - they can also get stuck fom overheating - particularly if they were a tight fit in the first place.

Always a good idea to pull them out once a year and give the motor a blow out with compressed air - put the brushes back the exact same way they came out.

Inspect the trailing edges of the brushes and the com for signs of arcing, brush bounce etc - if the com looks a mess - it might be in need of a skim.

Ken

 

[n4zou]

I had that same problem with the starter motor on my scoot. I opened up the starter and found the brush slot had never been deburred. The brush had hung up in the slot. A new starter would have cost over $100. I cleaned up the slot with some jewellers files, reassembled the starter, and put it back on the scoot. It spun the engine over faster than it ever had before.