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Posted: Fri May 09, 2014 7:38 pm
by JPG
'North' poles Attract 'south' poles.
Those refrigerator magnet sheets do not have well defined poles.
Posted: Fri May 09, 2014 7:41 pm
by dusty
JPG40504 wrote:'North' poles Attract 'south' poles.
Those refrigerator magnet sheets do not have well defined poles.
Really now. Are you sure about that?
Actually, if you put a sheet magnet (refrigerator magnet) under a piece of glass and spread iron filings on top of the glass you will see evidence of the pole arrangement. The issue is not that the poles are ill defined. The issue is that the magnets are weak.
Posted: Fri May 09, 2014 7:42 pm
by algale
dusty wrote:This really depends on what one is trying to accomplish. All that I was thinking about is making the main table attractive to the Wixey or Angle Cube.
What I have witnessed thus far has not been strong enough for anything like a rip fence held in place by a mag switch. However, I suspect that the field strength of a mag switch is many times stronger than what I have been tinkering with.
A fist full of nickel size rare earth magnets held in place by a shallow puddle of epoxy might work. I have, somewhere, six of those magnets. Do you think I can find them.
BTW, they will definitely align themselves but I don't know if in so doing the field strength increases or decreases. Sure wish I had paid better attention in school.
My magnetron magnet would hold that mag switch just fine. So there must be a compromise position somewhere in between the magnetron and refrigerator magnet.
BBs don't work, at least mine won't. They are not magnetic]Ball bearings[/URL], maybe.
Interesting about the BBs. Ball bearings likely are magnetic. Steel shot surely is.
Posted: Fri May 09, 2014 10:06 pm
by JPG
dusty wrote:Really now. Are you sure about that?
Yes!!!!!!!
Posted: Sat May 10, 2014 12:00 am
by rcplaneguy
Remember not to put your wallet on these tables once you mount magnets. If you want your credit cards to work.
Posted: Sat May 10, 2014 7:43 am
by dusty
I have come to the "unscientific" conclusion that this will not be practical for most of the proposed applications. It may work for applications that utilize a mag switch. I don't have one but I assume the field strength is much greater than any of the magnets (other than the maggie) I have to test with.
Supporting information: When I position the magnetron magnet beneath the table it grabs onto anything magnetic on the table top (the table does not appreciably diminish the magnetic field strength).
[ATTACH]24980[/ATTACH]
Posted: Sat May 10, 2014 9:24 am
by rlkeeney
algale wrote:Interesting about the BBs. Ball bearings likely are magnetic. Steel shot surely is.
BBs are normally copper plated steel.
Posted: Sat May 10, 2014 12:47 pm
by dusty
The BBs that I have are from a time capsule.
They are Daisy Red Rider brand and are almost as old as I am. They were part of what I accumulated from the house that I lived in before high school.
There is no telling except that they are not magnetic.
Posted: Sat May 10, 2014 3:51 pm
by benush26
Last night I placed a couple 1/2" rare earth magnets on either side of the table insert opening to see of they might hold my Wixey depth gauge in place. There is enough holding power (without being too strong), but because of the webbing enforcement on the bottom side. I can't place them in the center line. I've decided to get some 1" magnets to see if they would have enough power to keep the gauge centered,
but that got me thinking about Gene's needs and wondered if a row of approximately 10 1" or larger magnets glued front to back would give enough of a field to hold the Magswitch. There are webbing structures, but I think something similar to this could be done
[ATTACH]24981[/ATTACH]
I haven't looked for a source for rare earth magnets larger than 1", but maybe larger would be better??
Thanks to Dusty for his drawing
Be well,
Ben
Posted: Sat May 10, 2014 3:56 pm
by dusty
benush26 wrote:Last night I placed a couple 1/2" rare earth magnets on either side of the table insert opening to see of they might hold my Wixey depth gauge in place. There is enough holding power (without being too strong), but because of the webbing enforcement on the bottom side. I can't place them in the center line. I've decided to get some 1" magnets to see if they would have enough power to keep the gauge centered,
but that got me thinking about Gene's needs and wondered if a row of approximately 10 1" or larger magnets glued front to back would give enough of a field to hold the Magswitch. There are webbing structures, but I think something similar to this could be done
[ATTACH]24981[/ATTACH]
I haven't looked for a source for rare earth magnets larger than 1", but maybe larger would be better??
Thanks to Dusty for his drawing
Be well,
Ben
You weren't suppose to flip it over to see the unfinished bottom side.
I ran into trouble dealing with Sketchup when trying to do the bottom side. That's why the extension tables are so plain.