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Your Old Dog
02-07-2008, 06:03 PM
I think it was Frank Ford who first drew my attention to these little neodynioumlwoqrst uv (sp) magnets to hole post notes for the shop.

Well I orderedd $25.00 worth of the 3/8 round by 1/2 inch long ones. (about 20) Everywhere I turn I am finding great uses for them. Here's a scatter shield I built for my mill to keep my floor cleaner (more on that in another post). The black frame you see is actually photography gaffers tabe. There are two 1/2 aluminum studs tapped on one end and slightly undersize holes drilled in the other end. A magnet is pressed into each undersized hole. The other end of the aluminum is threaded so that it can be bolted to the scatter shield. The 2 magnets grab the back of the vice and work to perfection. Any crash and the magnets release. In this photo the two wings are folded back against the main board.

I noticed the hole in my swarf brush and forced a magnet into the plastic handle. Now I don't have to stab my fingers in swarf as I pick up the brush.

http://bbs.homeshopmachinist.net/http://inlinethumb53.webshots.com/40436/2007785000102651310S600x600Q85.jpg (http://good-times.webshots.com/photo/2007785000102651310Cellwl)

BobWarfield
02-07-2008, 06:38 PM
I use welder's "arrow" magnets for various things. There's one stuck to every machine where the chuck key for the machine goes. They're handy to hold a print. And in a pinch, you can hang a variety of other things on one.

Cheers,

BW

Dragons_fire
02-07-2008, 06:51 PM
i use these little magnets to hold my wrenches for my lathe to the gearbox end, to hold chuck keys to the lathe tailstock and to my mill and drills, to hold drawings up where i can see them, and to hold small parts and parts dishes while assembling stuff....

Fasttrack
02-07-2008, 07:03 PM
Nifty ... where can i obtain some of these wonderous little devices? :)

Evan
02-07-2008, 07:03 PM
I use them to grab cast iron dust when drilling it. Then the question is how to clean the cast iron dust from the magnets. Pinch off as much as you can with your fingers and remove the rest with sticky tape, duct tape is good. Magnetism is no match for Van der Waals forces.

rollin45
02-07-2008, 07:05 PM
I like the little magnets as well, but one problem with them is that over time they accumulate all kinds of swarf and debris. If the magnets are very strong, its almost impossible to get that crap off of them. So I have started wrapping them in a layer or two of seran wrap, then when they get loaded up, I just peel off the wrap and chuck the whole mess. Re-wrap and good to go for another while.

rollin'

Ghop Shop
02-07-2008, 07:06 PM
Old computer hard drives are a good source for very powerful magnents.

Evan
02-07-2008, 07:07 PM
They don't work quite as well when bagged.

Fasttrack
02-07-2008, 07:11 PM
magnetism is no match for van der waals forces? ;)

Your Old Dog
02-07-2008, 07:27 PM
I got mine off a guy on ebay. I think this is the right seller.

http://cgi.ebay.com/10-PC-1-2-x1-2-NdFeB-Neodymium-Rare-Earth-Magnet-N42_W0QQitemZ310019693575QQihZ021QQcategoryZ29402Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem

Incidentally, I saw his ad come up on this board as a sponsor.

Fasttrack
02-07-2008, 07:28 PM
I got mine off a guy on ebay. I think this is the right seller.

http://cgi.ebay.com/10-PC-1-2-x1-2-NdFeB-Neodymium-Rare-Earth-Magnet-N42_W0QQitemZ310019693575QQihZ021QQcategoryZ29402Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem

Incidentally, I saw his ad come up on this board as a sponsor.


thanks! i may need to make a purchase :D

tony ennis
02-07-2008, 07:35 PM
"Then the question is how to clean the cast iron dust from the magnets."

Put them in a zip-lock baggie before using them. The swarf sticks to the bag. Then, turn the bag inside out and the crap is in the bag, and the magnet is outside.

I'm going to use similar magnets to cover the oiler holes on my lathe. The mismatching (or simply missing) Zerc fittings annoy me.

BobWarfield
02-07-2008, 07:36 PM
Then, turn the bag inside out and the crap is in the bag, and the magnet is outside.

This works for dogs too, I might add.

BW

Thomas Staubo
02-07-2008, 07:51 PM
Then, turn the bag inside out and the crap is in the bag, and the magnet is outside.
This works for dogs too, I might add.

BW

What!? :eek:

Turn the dog inside out??? :confused:

pntrbl
02-07-2008, 08:33 PM
Old computer hard drives are a good source for very powerful magnents.

I used to have a lot of fun with ceranium(sp) cobalt magnets at a drive manuf called Micropolis back in the 80's. Gawd them things were powerful!

They'd attract thru yer hand for one. If you let two of 'em get together at the corners with a pinch of your skin in between they'd bring blood. We used to stack a few and attract another straight up in the air for several inches. Hit so hard they'd crack sometimes.

I took a mess of 'em to show and tell when my daughter was in kindergarten and sent all the kids home with just one. Couldn't have nobody bleeding. :) Awhile later one of the Mom's asked me what she had to do to get one off her fridge. :eek:

SP

darryl
02-07-2008, 10:42 PM
Now I'm confused- Van der Waals sounds dutch, not scotch- :)

TGTool
02-07-2008, 10:48 PM
This works for dogs too, I might add.

BW

Outside of a dog, a book is man's best friend. Inside of dog it's too dark to read. - Mark Twain

Doc Nickel
02-07-2008, 11:45 PM
That's actually a Groucho Marx quote, I believe.

Still good. :D

Doc.

Fasttrack
02-08-2008, 12:27 AM
That's actually a Groucho Marx quote, I believe.

Still good. :D

Doc.


Yes - a Groucho Marx quote ... he's full of 'em :D

Some of my favorites ;)

A black cat crossing your path signifies that the animal is going somewhere.

A child of five would understand this. Send someone to fetch a child of five.

I find television very educational. Every time someone switches it on I go into another room and read a good book.

Paul Alciatore
02-08-2008, 12:50 AM
magnetism is no match for van der waals forces? ;)


Evan was referring to the forces between molecules, AKA chemical forces. Adhesives or glues come into very intimate contact with the substances they join and hence these molecular forces are at play in forming the bond.

They are named after the Dutch physicist J. D. van der Waals.

If you want more, Google "Van der Waals force".

I also use duct or duck tape to remove swarf from magnets. I keep several in the bottom of my container of Tap Magic and they collect the magnetic swarf that the brush deposits there. The duct tape seems to work best for this.

Evan
02-08-2008, 02:14 AM
Paul has it right. Here is a pretty good explanation.

http://www.chemguide.co.uk/atoms/bonding/vdw.html

I should point out this is not what holds matter together but it is in large part what make things tend to stick together. That includes in large part the wringing effect of Johansson blocks and is how a gecko lizard is able to walk on a wall or even a window.

pntrbl
02-08-2008, 06:46 AM
Favorite Groucho "quote"

Sir, you are close to an idiot!

Groucho: Well I better step away ....

SP

Orrin
02-08-2008, 10:24 AM
I've never bought from this outfit, but if I ever get around to ordering some, it would most likely be this place:
http://wondermagnet.com/main.shtml

Here is an interesting magnet site:
http://www.rare-earth-magnets.com/magnet_university/magnet_university.htm

Another:
www.forcefieldmagnets.com/catalog/product_info.php?products_id=102

Orrin

Pete H
02-08-2008, 11:53 AM
Try American Science and Surplus - formerly "Jerryco" - for magnets. Only problem is, this place IS a "surplus" dealer, and you may not find the same things in stock from one month to another. www.sciplus.com/

Pete Heinlein, NJ

Evan
02-08-2008, 04:07 PM
OK, so, a few minutes ago I was gluing such a magnet to something and it didn't stick. So I took it into the next shop to grind off the nickel plate with the bench sander. I flipped on the sander and held the magnet to the paper with my fingertips. That didn't work out too well as the platen under the belt is steel. The magnet instantly stuck to the platen except it had a fast moving belt between. The magnet was then catapulted across the grinding shop and I heard it bounce off the wall. That was all for what seemed like two or three seconds and then I heard a very distinct and sharp !CLACK!. No rattle, no roll. It's somewhere in that room. There is a lot of metal in that room. It's almost like it was hovering around deciding what to stick to. I didn't bother looking for it. All I know is that it is still in the room somewhere. :rolleyes:

Weston Bye
02-08-2008, 04:30 PM
Think twice about grinding or otherwise removing the plating on magnets. The plated ones are usually neodymium and the plating is there to prevent corrosion. The neo- oxidizes and turns into a white powder and looses it's magnetism.

Even plated ones, if poorly plated, can corrode.

tony ennis
02-08-2008, 07:37 PM
And if the nickel plating is breached the magnets crumble.

Evan
02-08-2008, 07:48 PM
I've never had either result happen. If you want to glue them you need to rough up the surface. There are about six of the 1/2" supermagnets glued to the back frame of my mill. They hold the 50 lb counterweight in it's track so it doesn't rattle or vibrate. They don't quite touch the steel can that holds the lead so they are frictionless. They are still there and haven't corroded or crumbled.

dang
02-08-2008, 09:04 PM
On of my local surplus stores carries Neodymium Magnets. I use them for everything. Got 'em on every machine tool, and on the walls to hold up charts, lists and prints. I glue them to metal surfaces using two part epoxy. As stipulated above, this requires the surface be roughed up. But you wanna talk about permanent magnets!
I also use Magnets harvested from the insides of my old hard drives. They're REALLY cheap! When I'm forced to buy them, I drive home with the paper bag stuck to the top of my car's roof. :)

PaulF
02-08-2008, 10:18 PM
Hi,
I bought some real killer ones for a magnetic coupler on an under water motor.

Be careful they will erase your credit card stripes and magnatize your tools so they pick up swarf!!!
PaulF

darryl
02-08-2008, 10:22 PM
One day I'm actually going to build a direct-drive motor for the lathe using super magnets. I'll probably attach the magnetic component directly to the pulley and if I can I'll make the coil component without iron at all. I'll have to make dam sure that swarf can't get into it. It will be three phase at least, though it could be five phase.

I could use the actual circuitry from a vcr capstan motor to control commutation and speed- mostly what else is required is to interface the vcr motor drive signals to higher power electronics. Essentially, I'd just be expanding the size and power of a capstan motor, but using the same 'brains'.

I played with some small disc magnets one day, sticking them to a metal strip then heating them with a torch. Predictably, at a certain fairly low temperature, the magnetism disappeared and the magnets dropped off the metal strip. I managed to re-magnetize them, but didn't have the proper set up to do it fully.

I went into a restaurant one day and took the clock off the wall (where it couldn't be seen very well) and hung it on one of the metal pillars using a pair of small nib magnets. The clock was fairly heavy, but it never slipped down.

It's interesting to see how you can destroy a ferrite magnet with one of these.

Fasttrack
02-08-2008, 10:31 PM
Paul has it right. Here is a pretty good explanation.

http://www.chemguide.co.uk/atoms/bonding/vdw.html

I should point out this is not what holds matter together but it is in large part what make things tend to stick together. That includes in large part the wringing effect of Johansson blocks and is how a gecko lizard is able to walk on a wall or even a window.


I know what Van Der Waals forces are, i was referring to the fact that they are intimately related to magnetism on the relativistic and quantum levels.

Evan
02-09-2008, 02:53 AM
Yes, you are right. However, they don't operate in the same way as gross domain electromagnetism, especially with respect to distance as a power law force. All interactions between gross quantities of matter at the macroscopic level are strictly electromagnetic with the exception of particle mediated events in radionuclides. Good thing too or everything would be stuck to everything. The gecko isn't in any danger of falling off a wall. The Van der Waals forces in his foot pads are strong enough to support many times his body weight. The real question is how it manages to peel it's feet loose.

Doc Nickel
02-09-2008, 03:25 AM
The little article I saw on that (the gecko pulling his foot loose) showed that they curl (or roll) their toes up- like the end of a classic elf shoe.

With the majority of the effective surface in the toes, once they're "unhooked" due to the rolling, it's easy for the gecko to shift that foot, and once shifted it "unrolls" the toes again, helping assure complete contact.

At least, that's what the video showed- they shot some high speed as a gecko walked across some glass. Fascinating stuff.

And as for the magnets corroding, I was told it had to do mainly with moisture- like clean steel, it'll be fine for years in a dry environment, but it'll corrode overnight when it's humid. Also, if the "roughened" side is subsequently sealed with the epoxy used to adhere it, it shouldn't corrode. Your mill magnets should be fine, unless you add flood coolant. :D

Doc.

Your Old Dog
02-09-2008, 06:35 AM
I went into a restaurant one day and took the clock off the wall (where it couldn't be seen very well) and hung it on one of the metal pillars using a pair of small nib magnets. The clock was fairly heavy, but it never slipped down.

Remind me never to go to lunch with you :D

Now that we got all this Geico stuff figured out maybe we can save a few bucks on our car insurance.

Peter Neill
02-09-2008, 09:04 AM
I have one of the small (6mm dia) magnets epoxied onto the the end of a 6" long, 6mm dia piece of mild steel rod.
It's invaluable for pulling small spacer blocks, bearing balls, springs, and similar items from the bottom of deep holes, particularly where they have been retained by a grub screw (set screw to you lot :) ).

Very useful if you have ever stripped a Bridgeport head down for repair.

Peter

BigBoy1
02-09-2008, 09:05 AM
I bought a bunch of the flat disc neodynuim magnets from www.magnet4less.com and used them to hold the tarp on my truck. I made small colth bags for each magnet and left a small cloth strip to get a hold of the magnet. The cloth prevents the magnet from scratching the paint surface and the strrip makes removal easy. They really hold the tarp as the strongest winds have not removed the tarp from the truck. The trick is to make sure the tarp is tight to the truck's surface so the wind cannot get under the tarp.

Bill

Fasttrack
02-09-2008, 11:56 AM
Yes, you are right. However, they don't operate in the same way as gross domain electromagnetism, especially with respect to distance as a power law force. All interactions between gross quantities of matter at the macroscopic level are strictly electromagnetic with the exception of particle mediated events in radionuclides. Good thing too or everything would be stuck to everything. The gecko isn't in any danger of falling off a wall. The Van der Waals forces in his foot pads are strong enough to support many times his body weight. The real question is how it manages to peel it's feet loose.


Yep - its just that modern, entry level textbooks often equate "Van Der Waals" forces with London Dispersion forces and then seperately identify hydrogen bonding, dipole-dipole and etc. And since London dispersion forces exist because of magnetic moments your statement just struck me as sort of silly if you think about it too much.

Of course its perfectly valid, as you point out, on the macroscopic level where it "matters" and since Van Der Waals forces are generally considered to be the entire range of intermolecular forces, it makes perfect sense. :)

Evan
02-09-2008, 03:33 PM
I see you didn't catch my goof in that statement. I should have excepted gravity too. :rolleyes:

darryl
02-09-2008, 03:34 PM
I had a van der wall force experience once. I accidently hit the wall of my garage with the van. I don't know if the metal curled away from the wall, but I got unglued easily. A bit of molecular displacement was evident in the side of the van. It was not a particularly magnetic moment for me.

Fasttrack
02-09-2008, 06:22 PM
:D :D



... I'm going to go do something in the shop now... really i am.

dewat
02-09-2008, 08:06 PM
This is a black sand magnet used in gold mining, I use it to pick up swarf, it works like a syringe, put your fingers on each side and push with your thumb, when your ready to dump its spring loaded, so just release thumb pressure, originally it had one of these Alnico washer magnets in it, I pried it apart and added another. Haven't done it yet but I was thinking of using the same basic idea with more powerful magnets using pvc pipe or whatever works, it wouldn't need a spring in it if you put a couple of rings on each side for your fingers and one for your thumb, or just use both hands.

http://i81.photobucket.com/albums/j218/dewat/Gordy116.jpg