Using magnetic chuck for work holding

[Neo]

Hi All,

I am contemplating on buying the Pocket NC v2, which I intend to use to cut parts out of a 20 gauge, 12"x12", 430 steel plate. To hold the work piece, I was thinking of using a magnetic chuck bolted either directly to the B plate or via the Aluminum sacrificial plate fixture. Does anyone have any experience using magnetic chucks on the Pocket NC v2 and if so, what is the best way to attach a magnetic chuck to the machine?

Thanks,

Neo

[jaco...@gmail.com]

I have no experience with magnetic chucks, but you won't be able to hold a 12" x 12" steel plate for both size and weight limits. The B table has a diameter of about 3" (though if you are creative you can hold a larger diameter and the height limit is about 3.25" if you are planning to rotate the Axis by 90 degrees.

[Jonathan]

Neo,

Like the other poster mentioned, the mag base that you are discussing is too large for the Pocket NC. 

In addition, since the Pocket NC uses Hall effect sensors for the home switches, a strong magnetic field would most likely cause problems with the machine's homing behavior. 

Jonathan 

[Neo]

Hi Jonathan,

I can switch to a smaller workpiece (6"x6"). Is that size supported? Also, my understanding of Hall effect sensors is that the potential difference in the sensor circuit crosses the detection threshold when the magnetic field direction is perpendicular to that of the sensor semiconductor circuit. In YouTube videos I see that the home button face is perpendicular to the default resting position of the B table top. So, the sensor circuit orientation should be parallel to the magnetic field emanating from a magnetic chuck mounted on top of the B table in the default resting position and hence should not interfere with the sensor operation. Is this understanding correct? If that is the case a magnetic chuck should still be usable if the machine is programmed to hold the B table in the default resting position when it seeks the home button.

Thanks,
Neo

[Jonathan]

Neo,

No, 6x6 would still be too large. 

I am not confident enough in my understanding of how the sensors work to say whether or not the magnetic chuck would affect the Hall Sensor or not based on the sensor's orientation. I have observed that a magnetic base for a dial indicator does affect the hall sensors when I mount it on the machine so I would expect that the magnetic chuck would have a similar effect.

Jonathan