how do switchable magnets work?

[kd0afk]

I did a little research on the subject but still don't understand. The info I could find says that they have two magnets inside a horseshoe bit o took one apart and it was a cylindrical magnet in a cylinder. Nothing like the descriptions. And the magnet was an alinco magnet. I would like to try and make my own magnetic bases but with stronger magnets.
Any help on this one?

 

[GailInNM]

Do a Google search on these and all is revealed.
patent 4251791
patent 4329673
Gail in NM

 

[kd0afk]

Do a Google search on these and all is revealed.
patent 4251791
patent 4329673
Gail in NM

Yeah I saw those but when I took mine apart the housing isn't magnetic. I also saw a different design that uses two disk shaped magnets in a horseshoe. It also doesn't explain starretts design. The starrett bases use a push button not a turning motion.

 

[kd0afk]

I changed my search parameters and found out more. It looks like there are three different types. One like mine which is a diametrically magnetized alinco cylinder housed in a block that is aluminum sandwiched between iron. The second is two disk magnets where one is fixed and one rotates and I think those are in a magnetic housing, I'm not sure. The third is the starrett push button style. I can't find any info on it but I think it's more like a magnetic vise with thin magnets alternating and spacers.
Maybe I'll just buy my bases. I can get the parts I need but it's cost prohibitive and I will most likely need a mill to make them.
Oh well.

 

[purpleknif]

If you soak the magnets in liquid nitrogen they get WAY stronger. Just be sure to bring them back up to room temperature slowly. I use a "Little Playmate" 6 pack cooler. Let them soak until they quit boiling then just let the nitro boil off.

 

[kd0afk]

There's nothing wrong with using just a regular magnet instead of a switchable one is there? Switchable magnets are very convenient but I can do ok with just a magnet.

 

[kd0afk]

If you soak the magnets in liquid nitrogen they get WAY stronger. Just be sure to bring them back up to room temperature slowly. I use a "Little Playmate" 6 pack cooler. Let them soak until they quit boiling then just let the nitro boil off.

I live in a town that has four hardware stores to serve 6800 people and none of them even have a full set of letter drills, I doubt that I'll find liquid nitrogen. And if I do how would I transport it. They don't even sell dry ice around here.
Great tip but I won't be able to utilize it. I have heard that cryogenic treatments of metals make them perform better like razors and musical brass instruments.

 

[purpleknif]

Actually, you get liquid nitrogen at a welders supply. Where I get mine its free if I go on a Saturday ever since I took them McDonalds gift cards. You can transport it in a thermos bottle if its vented. Without a vent you'll have a BOMB
I used to treat R/C race car motors 5 at a time. Put enough juice in to cover them, close the cooler, get home and open it up, let it boil off & done.
Mags got way stronger giving more torque & rpm.

 

[kd0afk]

Welders supply? You mean ace hardware?

 

[Rivergypsy]

Hi,

I've designed a few bases like this lately, and you want diametrically magnetised rod magnets between two pole pieces, so you can rotate the poles in an out of alignment. If you want a diagram then pm me and I'll send it on Monday.

Easy job to do, and you can do two magnets in a little trick for serious grunt.

Dave

 

[purpleknif]

Welders supply? You mean ace hardware?

No, a welding supply place where they sell welding gasses. Oxygen, acetylene, argon and such.

 

[kd0afk]

Yeah ace hardware. That's it for this town. There's no welders supply place here. Gotta go 50 miles to the next town for that and I don't have a car.

 

[kd0afk]

OK, upon closer inspection with a magnet and a file I found that the body is made of what appears to be aluminum sandwiched with steel. Did they braze them together? Could I bolt the layers together? I found diametrically magnetized magnets with a through hole and holds 78lbs. It's 1"x1.5" long with a good sized bore. I betcha I can make one.
Would brass separating the poles work?

 

[kd0afk]

Sorry

 

[kd0afk]

Could I use stainless steel as the center layer and braze the layers together?

 

[Rivergypsy]

Hi,
Brass should be fine, and I'd assume the layers are bonded with a structural adhesive, but I'd be careful of stainless unless you're 100% it's not magnetic - too many of them are.
If you've got 78lb on one, do try two - it's an education on how two fields multiply ;0)

Dave

 

[kd0afk]

Hi,
Brass should be fine, and I'd assume the layers are bonded with a structural adhesive, but I'd be careful of stainless unless you're 100% it's not magnetic - too many of them are.
If you've got 78lb on one, do try two - it's an education on how two fields multiply ;0)

Dave

Are you talking about side by side or end to end?
And brazing should work with steel and brass, right?

 

[Wizard69]

One source of magnets that are really powerful is disk drives. You have to disassemble the drive to get to the magnets but on the other hand you gain a nice piece of castable aluminum. If there is a local guy doing PC repairs you might be able to score broken drives cheap or even free.

On approach that might work for you is a cam release magnetic stand. Here a lever and cam arrangement is used to pry the magnet assembly off the piece you are stick to. The problem is the magnets never really turn off, you just force them to break free. Such magnetic arrangements are probably best for semi permanent installations such as lamp assemblies, lube nozzle stands or fan assemblies.

 

[Rivergypsy]

For switchable you really need rod magnets, whereas disc drives have some odd shapes. I agree though that the neodymium magnets have some serious grunt.

For two, did you get the emailed pic? You want side by side in NSSN or SNNS ;0)

 

[kd0afk]

For switchable you really need rod magnets, whereas disc drives have some odd shapes. I agree though that the neodymium magnets have some serious grunt.

For two, did you get the emailed pic? You want side by side in NSSN or SNNS ;0)

I got the pics. Maybe when I get into the advanced class I'll tackle dual mags but for now it's going to be a single neo in a steel and brass case.