A word on magnetic tool holders

[Quinn McCarthy]

I bought a double magnetis strip to hold my turning tools and it was so bad it wouldn.t hold my smallest turning tools. I was thinkng about 112lb magnets I found on sale online. That should hold my biggest tools.

Quinn

[Jamie Straw]

A couple of my early, cheap tools have become lightly magnetized, for seemingly no reason -- a 1" roughing gouge mostly notably. I actually like it, 'cause when I lay the credit-card diamond hone on it, it lays perfectly flat on the bevel, with just a light magnetic tug. Have no idea how it got magnetized, I never have held it with a magnet to anything.

IMHO, a good use of magnets for tool holding would be to combine them with a slanted wood holder, just enough magnetic hold to keep them from getting jostled out when removing an adjacent tool. On my list of "to build" accessories.

[Jamie Straw]

Try Lee Valley -- their magnets and magnetic accessories are quite good.

[Kyle Iwamoto]

My Thompson V-gouge has gotten magnetized also, so I don't think cheap tool has anything to do with that random magnitization. That gouge has never seen a magnet. It has the most magnetism....

I use a HD magnetic bar on my mini lathe bench so the toys, er tools don't roll off. I did put a strip of duct tape on the magnet thinking it would help keep tools from direct contact with the magnet. Unsure if that has any effect.

[Paul Lawrence]

I did put a strip of duct tape on the magnet thinking it would help keep tools from direct contact with the magnet. Unsure if that has any effect.

The only effect that has is to reduce the "pull" of the magnet on the tool. Similar to the effect of a refer magnet trying to hold too many pages of notes to your refer door.

One way to keep stray (electrically induced) magnet fields from magnetizing your tools is to "encase" your tools in a soft iron pipe with an iron cap on one end. The pipe will contain the magnetic fields (along with the cap at one end. There will be some "leakage" of the field at the open end of the pipe, but it will be very small.

[John K Jordan]

If you have a tool made from a "steel" that can be magnetized by sitting in the earth's magnetic field, you wouldn't be able to cut with it for very long. That's why your standard "horseshoe" magnet is made from "soft" material.

Sorry, this makes no sense to me. I use Thompson Tools made from some of the best steel available for turning, 10v(A-11), very hard and can easily be magnetized.

The softer irons and steels do not make good magnets. That's the reason electromagnets have been made with soft iron so the core will not remain permanently magnetized when the field is switched off.

JKJ

[John K Jordan]

The Earth's magnetic field is so weak it would have negligible effect on a piece of metal. ...

Yes, I can understand why you might think that. On the surface it doesn't seem logical that the weak magnetic field can magnetize anything. However, this is true. Here is an answer to this very question from the U of Illinois Physics department: https://van.physics.illinois.edu/qa/listing.php?id=436

In fact, making a magnet this way is a common science experiment for kids. To convince yourself, try it!
http://classroom.synonym.com/magnetize-things-6377.html - striking method
http://m.wikihow.com/Magnetize-Steel - method three
(Just remember that some types of ferromagnetic materials cannot be magnetized by any method.)

Note that the steel will eventually become magnetized without striking, but this will take a long time (months or even years). The vibration causes this to happen immediately. The physics article describes magnetism of railroad rails due to vibration from the train wheels.

30 years ago we did a simple experiment: using the compass technique I mentioned, we checked a steel object and noted the magnetic field orientation in the object. The object was inverted and rechecked much later - the field had inverted!The vibration principle is why I wondered if lathe tool vibration could be responsible for magnetized tools.

Note the magnetism I observed at the CBN wheel was very weak but still enough to hold fine steel dust. I did not experiment - perhaps the Tormek itself or the action of the CBN wheel itself contributed.

JKJ

PS: I do not claim to be an expert in the physics of magnetism, just a curious amateur. However, for many years I worked in a laboratory with experts - we had many interesting discussions, projects, and experiments. For good fun, try magnetically levitating a PM rotor in an extreme vacuum and spinning it faster and faster with magnetic fields until it explodes! Actually, don't try this at home...

[Paul Lawrence]

Hey, everything is relative.

Sorry I dumped on your "best steel" pride. Didn't mean too.

Sorry, this makes no sense to me. I use Thompson Tools made from some of the best steel available for turning, 10v(A-11), very hard and can easily be magnetized.

The softer irons and steels do not make good magnets. That's the reason electromagnets have been made with soft iron so the core will not remain permanently magnetized when the field is switched off.

JKJ

[John K Jordan]

Hey, everything is relative.

Sorry I dumped on your "best steel" pride. Didn't mean too.

This has nothing to do with pride in tool ownership. This is about physics and material properties.

Perhaps I misunderstood your point. I thought you wrote that a tool easily magnetized would not hold an edge very long while turning. That turns out not to be the case. The tool steels that hold their edge longest such as the 10V can indeed be easily magnetized. I have seen it with my own eyes. I have demagnetized them many times.

Of course the reason they became magnetized is a matter of conjecture until tested further.

JKJ

[Paul Lawrence]

Sorry, John. We don't have the time or the audience.

[Lenore Epstein]

Perhaps newer holders are stronger?

True--at least if they use rare-earth magnets. Lee Valley does sell them, along with magnet cups & washers, but they're far cheaper from online sources, especially eBay, if you're an eBay-ing sort of person.

Anyhow, the 3" diameter rare earth magnet I scavenged from a gadget from Ace Hardware sticks so well to plane irons while I flatten the iron's back against abrasive stones (thereby protecting my fingertips from getting sanded off) that the only way to get it off the iron is to brace its side against a table edge, and push down on the blade firmly (using a rag to protect my precious fingers from edges and burrs) to slide it off sideways. That's totally fine, though, because the cool little thing literally saves my skin.

But after my favorite flathead screwdriver spent a few weeks stuck to the magnet it was so strongly magnetized that I had to guide it into a screw's slot with my free hand to keep it from trying to become one with the top of the screw. After reading this thread a few days ago I stuck the screwdriver's shaft to the magnet with the magnet's 'handle' aligned with the screwdriver so I'd remember which way to position it if it didn't work the first time.

I'm happy to report that today the screwdriver is only lightly magnetized--barely enough to move screws an inch or so away on a table, but not enough to pick them up or to stick stubbornly to anything. The magnet now lives in my waterstone box, which stores nothing ferrous at all, and I'm a happy camper again.

If I were shopping for a magnetic tool holder I'd look for one designed for light tools that either use a lot of weak magnets or well-spaced small rare earth magnets.

[Dan Hintz]

Yes, I can understand why you might think that. On the surface it doesn't seem logical that the weak magnetic field can magnetize anything. However, this is true. Here is an answer to this very question from the U of Illinois Physics department: https://van.physics.illinois.edu/qa/listing.php?id=436

In fact, making a magnet this way is a common science experiment for kids. To convince yourself, try it!
http://classroom.synonym.com/magnetize-things-6377.html - striking method
http://m.wikihow.com/Magnetize-Steel - method three
(Just remember that some types of ferromagnetic materials cannot be magnetized by any method.)

My original post said "negligible effect", and your first link also mentions the resulting magnet (after a good pounding, I might add) is quite weak (likely about enough to move a compass needle).

Your other two posts show metal acquiring a magnetic effect after rubbing with another magnet... not quite the same thing as leaving it in the magnetic field of the Earth.

[Geoff Whaling]

On a slightly different note about the potential downsides of strong magnetic fields and magnets in shops / sheds - a word of caution to turners who have surgically implanted medical devices - Pacemakers, Defibrillators, neuro stimulators, incontinence sacral nerve stimulators etc.

Read up on the cautions / warnings your device supplier has published on your device. Strong magnetic fields may interfere with the devices normal operation which could either get, messy, painful or result in an inappropriate therapy being delivered.

Magnetic tool holders at about chest height and strong magnets on headstocks are a particular risk for Pacemakers & Defibrillators.