jhovel
13th Apr 2016, 11:46 PM
I am considering building a small permanent magnetic chuck for my rotary table.
The constuction is simple: a slotted aluminium or brass front disc, a steel back disc with mounting provisions and a spacer/sealing strip around the outside. The latter may be made from a short ring of pipe, counterbored to fit the front and back discs, to fix them and to space them apart.
The front disc would have slots milled through to position and locate soft iron pole strips - flush with the front and protruding to cover the entire side of one of the magnets. Thus passing the magnetic field to the face of the front disc. I would epoxy all the pieces to each other and to the front disc. Maybe all of it.
The general arangement of magnets and pole pieces could be something like this:
362010
The first question is: would that work at all? I imagine that a workpiece on the front of the chuck would complete circuits of magnetic force lines and thus get 'stuck'.
The second question is, if I arrange additional magnets facing opposite directions (N/S), would they support or hinder/repel the magnetic lines. I realise that they will be facing N-N and S-S, but with the pole pieces in between.
Like this:
362011
The last question is, since there is no mechanism to turn the magnets off, do I have to have 'keepers' to preserve the magnets and/or to stop them picking up iron dust from everywhere while not in use?
All comments and information is appreciated.
The constuction is simple: a slotted aluminium or brass front disc, a steel back disc with mounting provisions and a spacer/sealing strip around the outside. The latter may be made from a short ring of pipe, counterbored to fit the front and back discs, to fix them and to space them apart.
The front disc would have slots milled through to position and locate soft iron pole strips - flush with the front and protruding to cover the entire side of one of the magnets. Thus passing the magnetic field to the face of the front disc. I would epoxy all the pieces to each other and to the front disc. Maybe all of it.
The general arangement of magnets and pole pieces could be something like this:
362010
The first question is: would that work at all? I imagine that a workpiece on the front of the chuck would complete circuits of magnetic force lines and thus get 'stuck'.
The second question is, if I arrange additional magnets facing opposite directions (N/S), would they support or hinder/repel the magnetic lines. I realise that they will be facing N-N and S-S, but with the pole pieces in between.
Like this:
362011
The last question is, since there is no mechanism to turn the magnets off, do I have to have 'keepers' to preserve the magnets and/or to stop them picking up iron dust from everywhere while not in use?
All comments and information is appreciated.