2 of the solenoids controlling the brake and speed on my BP CNC mill have gone open.
I need to make a new bobbin and wind new ones if possible. The mechanical valves are good and are built on a heavy manifold.
You can see the 2 solenoids I removed here, and the bottom one is the last good one, which I assume will be dying shortly....

The windings are sealed in a molded plastic case:

Smashing one open yields:

The wire measures .007" dia after I burnt off the insulation, and about .0078" with the enamel.
Resistance of the good one measures 69.5 ohms, which at 24 vdc yields about 345 mA of current which seems high for #33 wire, and has me wondering if that has something to do with 2 of these opening up. Maybe my flyback diode should be at the solenoids, and not at the power supply.
Anyway, I ordered a roll of #33 wire and I would like to attempt to machine a bobbin and wind it.
Here is a drawing I did showing what size I need the bobbin to be.

So the question becomes, what type of plastic would be good to use for this bobbin? The thin .04" walls make me nervous in plastic. I have a piece of UHMW round on the shelf that would be perfect, but I know that UHMW is not the best turning material.
How about ABS? Garolite?
I need to make a new bobbin and wind new ones if possible. The mechanical valves are good and are built on a heavy manifold.
You can see the 2 solenoids I removed here, and the bottom one is the last good one, which I assume will be dying shortly....

The windings are sealed in a molded plastic case:

Smashing one open yields:

The wire measures .007" dia after I burnt off the insulation, and about .0078" with the enamel.
Resistance of the good one measures 69.5 ohms, which at 24 vdc yields about 345 mA of current which seems high for #33 wire, and has me wondering if that has something to do with 2 of these opening up. Maybe my flyback diode should be at the solenoids, and not at the power supply.
Anyway, I ordered a roll of #33 wire and I would like to attempt to machine a bobbin and wind it.
Here is a drawing I did showing what size I need the bobbin to be.

So the question becomes, what type of plastic would be good to use for this bobbin? The thin .04" walls make me nervous in plastic. I have a piece of UHMW round on the shelf that would be perfect, but I know that UHMW is not the best turning material.
How about ABS? Garolite?
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