Rare Earth magnets

[bigsteel15]

I know there's been a bit of discussion but I have something specific in mind.
I'm thinking of making my BT3 cabinet modular so I can add a second saw if and when they go on sale up here in Canada or if I see the threat of them disappearing.
What I'm wondering is any thoughts on using RE magnets to hold the small removable cabinets to the base, as well as the tops so they could be moved around.
I was thinking if a space 1" magnets about 8-12" apart across front and back that it should hold strong enough.

Anybody try anything like this?

[LCHIEN]

I know there's been a bit of discussion but I have something specific in mind.
I'm thinking of making my BT3 cabinet modular so I can add a second saw if and when they go on sale up here in Canada or if I see the threat of them disappearing.
What I'm wondering is any thoughts on using RE magnets to hold the small removable cabinets to the base, as well as the tops so they could be moved around.
I was thinking if a space 1" magnets about 8-12" apart across front and back that it should hold strong enough.

Anybody try anything like this?

if you are a mechanical engineer you should understand this. Magnets are good in tensile load but not too good in shear load.
They don't want to pull apart easily (read strong) when pulled along their axis, but they don't hold nearly as well when you try to slide them apart.

As long as you try to hang something lightweight to the vertical metal side, it'll be OK, but if you try to hang a heavy load then it will want to slide down.

[bigsteel15]

if you are a mechanical engineer you should understand this. Magnets are good in tensile load but not too good in shear load.
They don't want to pull apart easily (read strong) when pulled along their axis, but they don't hold nearly as well when you try to slide them apart.

As long as you try to hang something lightweight to the vertical metal side, it'll be OK, but if you try to hang a heavy load then it will want to slide down.

Not mechanical engineer, but I know what you were getting at.
I should clarify my question.
When I say front and back I actually mean front and back of the top of a cabinet and bottom of a table surface or cabinet that would sit on top of that.
LV says the 1" magnet will hold 33 pounds, so I assume that would be in the "shear" direction if you were hanging something from it.
Therefore (6) of those should hold a 100# saw or 50# top from moving horizontally with no problem, right?

[LCHIEN]

Not mechanical engineer, but I know what you were getting at.
I should clarify my question.
When I say front and back I actually mean front and back of the top of a cabinet and bottom of a table surface or cabinet that would sit on top of that.
LV says the 1" magnet will hold 33 pounds, so I assume that would be in the "shear" direction if you were hanging something from it.
Therefore (6) of those should hold a 100# saw or 50# top from moving horizontally with no problem, right?

Not sure - don't have a mental picture of what you are trying to hold.

In-line (tensile):
Steel object<----->Magnet ---->force
will hold 33# by LVs number.


Shear:
Steel object<---->Magnet
...........................|
...........................|
...........................V
........................force

will hold much less than 33lbs.

You do need a plan for getting them apart when you need to though...

[pierhogunn]

Why not use the magnet as the male and female parts of a socket like lego's if you like... that way you could make these modular parts fit together any way that you please, just like cubes, with north faces and south faces...

Dan

[bigsteel15]

Not sure - don't have a mental picture of what you are trying to hold.

In-line (tensile):
Steel object<----->Magnet ---->force
will hold 33# by LVs number.


Shear:
Steel object<---->Magnet
...........................|
...........................|
...........................V
........................force

will hold much less than 33lbs.

You do need a plan for getting them apart when you need to though...

Washer in board/cabinet --> force
Magnet in cup in board/base cabinet <-- force

Washer could be replaced with second magnet in cup.

If I could post a pdf this would be easy to show. Do I need a webpage to do that?

[cgallery]

I think the problem is, that if you arrange things such that the magnets are strong enough to hold them together, you're gonna have a helluva time getting them apart again.

Thanks,
Phil

[Rob R]

I think the problem is, that if you arrange things such that the magnets are strong enough to hold them together, you're gonna have a helluva time getting them apart again.

Thanks,
Phil

i think this might be your biggest problem. you could use toggle bolts or something. maybe even oversize t nuts (with the prongs on them) and a rod that you lossen from the inside of the cabinet. that would be easy/strong/cheap enough i would think.

[RayintheUK]

If I could post a pdf this would be easy to show. Do I need a webpage to do that?

The valid file extensions include .pdf, so I guess you could just upload it like a .jpg or a .gif. I haven't tried it, but there is a 19.5Kb file limit, so the .pdf file will need to be pretty small. If it's too big and you want to show it, ping it to me, I'll host it and provide a link. HTH

Ray.

[bigsteel15]

The valid file extensions include .pdf, so I guess you could just upload it like a .jpg or a .gif. I haven't tried it, but there is a 19.5Kb file limit, so the .pdf file will need to be pretty small. If it's too big and you want to show it, ping it to me, I'll host it and provide a link. HTH

Ray.

Thanks Ray, I'll try that.

[bigsteel15]

Update!!

Mounted my BT3 on new cabinet today.
The saw is mounted to an open frame to allow cleaning underneath.
Then the frame has hinges on the left side of saw and RE Magnets on the right side.
WOW does it hold well. I used (2) 1" magnets, with the holder and washer countersunk to flush everything. With the saw mounted, I need to lift with quite a bit of force above both magnets to lift the assembly.

BTW, the mounting holes for a BT3000 to the base don't necessarily match up to the BT3100. Found this out the hard way, so now I only have (3) screws holding the saw to the base frame...for now.

[mdutch]

For my project, I used a 12" section of 2" round steel stock and wound it with 2000' of #14 insulated wire, mounted it to the main cabinet and used a steel plate flush-routed into the hanging cabinet to mate with it.

Then hooked the whole thing up to a 50A 24VDC power supply and turned it on.

It holds the cabinet on the mobile saw base just fine, but all my files and spare saw-blades went flying across the shop. I barely ducked in time...



(Seriously, the rare-earth magnet is an elegant solution. If you used some kind of keyed mating system like a peg & hole lego-style, or dado & rail alignment to register the top and bottom cabinet and keep it from slewing side to side, the rare earth magnets should work at least as well as velcro.)