Turning with magnets inside the wood

I would guess that most people see the subject and say "what the hell?" ... so bare with me on this ..

I make pepper grinder \ salt shaker sets for wedding gifts etc. I sometimes make them the same size and have the salt shaker the exact opposite as the pepper grinder (salt - convex shape where pepper would be concave) so that they kind of "fit" together. I was talking to someone about them and they said that I should try to really make them fit almost like a jig saw puzzle when they are side by side. Then the thought went further that it would be cool to have them "click" together magnetically. I was thinking that I could get those round magnets and embed them in the wood when I glue up the blocks before I turn them. After they are turned, they could be magnetically attracted to each other without seeing the magnets involved.

The question - would there be any "issues" with turning a glued up wood block with magnets on the inside?

Thanks Darren

Reply to
Darren
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How about boring the appropriate size hole for ring magnets and tacking a piece of dowel in the opening while turning. Bore, insert a screw, and break the (hot) glue to mount the magnet?

Experiment with magnets. Some of those rare-earth types would stick so tight as to make separation tough.

Reply to
George

I'll stay dressed, if it's all the same to you!

The only real "issues" would be avoiding hitting the magnets while turning and maybe a problem with balance, depending on how big the pieces are that you're working with, and how thin you turn them. Other than that, though, you shouldn't have any problems, as long as you use rare earth magnets and make sure you have the poles reversed on them, so they don't repel one another.

-- Chuck *#:^) chaz3913(AT)yahoo(DOT)com Anti-spam sig: please remove "NO SPAM" from e-mail address to reply. <

September 11, 2001 - Never Forget

Reply to
Chuck

The "issue" is going to be remembering where those magnets are so as to avoid cutting into them.

Barry

Reply to
Barry N. Turner

Nice idea. I've seen the same thing done before on wood sculpture and it was pretty cool where the pieces fitted together but could be removed and rejoined just by the hidden magnets. I've done this myself in some wooden puzzles where you have a "magic wand" over a piece and it unlocks part of the puzzle. Of course, the magic wand just has a magnet embedded in it as does parts of the puzzle.

I do it in woodturnings also a little bit but just for making miniature scale woodturnings as refridgerator magnets. I have this one little "knob" made from a really exotic and rare Magnetic Purpleheart wood that I take to demos. It actually sticks to metal! Of course, it's just a tiny rare-earth magnet embedded in there but you can't really see where it is or how it's in there. It freaks some people.

Your idea should work but as others have noted, you REALLY need to know where it is (location and depth) or else you're going to have it flying around the shop fairly quickly. You'll also need to have a maximum of about

3/16" of wood covering each one in the finished product, depending on wood specie, size of the magnet and how much force you want the two magnets to exert together. Most woods are far more dense than human fingers or hands but maybe not many heads (referencing the oft-demonstrated trick of putting these magnets on either side of a finger or hand and having them "stick") and it doesn't take much wood to degrade the performance of these really powerful magnets.

Just don't blame a "catch" on the magnet spinning too close to the gouge as you're turning it!

Let us know how it goes if you try it,

- Andrew

Reply to
AHilton

I wonder if it would fly out or immediately stick to the tool.

I don't think the wood will make much difference in the force between the magnets. It is a function of the separation and magnetic permeability of the material between them. I just tried a little experiment with some

3/8" dia. 0.2"thk. rare earth magnets (this size can already be tough to separate). I put them on either side of my finger and they stayed in place. I then tried it with a similar thickness of wood and noticed no difference. I also tried how close to the table one magnet has to be to get the other to jump up to it and noticed no difference with nothing, finger or wood. Just to put some numbers to this, the magnets would jump together when separate by about an inch with half of that space occuppied by wood. These might be larger than he is willing to embed.

Martin

Martin

Reply to
Martin Rost

Those revolving magnets can induce quite a current in metallic objects within the field. So I'd"

  1. Keep the speed below 3,000 RPM or so.

  1. Don't get your face in line with the spinning work, especially if you have any metallic fillings.

  2. Make sure to ground your gouge by contacting the tool rest before it contacts the workpiece.

Oh, and remove your watch before turning.

John Martin

Reply to
JMartin957

If you'd like the real skinny on using magnets in woodturning, you might try doing a search of the archives. I attempted to introduce the wonders of magnetism to this group and received nothing by loathing, scorn and weird prognostications of tools leaping off wall racks and impaling turners, magnetic induced warping of the ways, one's red blood cells leached of iron and on and on! Go for your idea with magnets! I am glad to see someone else picking up the banner!*G*

Reply to
Leif Thorvaldson

still got the article Leif? Duh!! I suppopse I had better lift a finger and do a little searching... why didnt someone work out what I wanted and have it ready for me??? why... why... ummmm why...

Tim GC

Reply to
Wobblybootie

I think it would fly out and not stick to the tool. Maybe, just maybe, the metal tool/toolrest/etc. would affect it's trajectory though IF the magnet decided to leave the wood really close to where the tool/toolrest was along the circumference of the wood piece it was embedded in. Depends on the speed at which the magnet was sent flying in the first place too I guess(ed).

To test this (I love testing things!), just about an hour ago I put a 2" wide skew (high carbon not HSS) in a vice pointing straight up and the wide, flat part parallel with me. I made a little magnet firing gun out of an old compressor pea-shooter I made once. Basically just a quick opening valve with a piece of small diameter PVC connected to the compressor. I set it up so that it would fire the magnets next too the skew at about 3" away. Then I tried it at 2", 1" and 1/2" away as well. I had the "gun" 2 feet away from the skew at all times. I shot it 20 times at each distance and then turned the skew 90 degrees so it was facing me with it's wide, flat part. My conclusion....

- The magnet never stuck to the skew until I was firing at the 1/2" distance and only when the skew flat part was faced away from me. Even then, it only stuck 4 times. The magnet wasn't traveling nearly as fast as it would have been spinning even at 1000 rpm *I think*. I didn't measure the speed but it didn't look as fast as those chucks of wood flying past me when I blow up a bowl.

- I'd like to set up again sometime and see if the trajectory of the magnet does, indeed, change as it passes by the steel tool.

Yeah, I was thinking more along the lines of the density of the wood and wood specie affecting how thin you could get the distance between the magnet and the outside of the wood. You can get hond. rosewood fairly thin and still be pretty strong. The same can't be said of sycamore, for instance. Those NIB magnets can get a pretty good pull going and I was wondering how much attaching/detaching of the two pieces of the turnings would hold up to such a thing. You'd need a greater distance between the 2 magnets (more wood between them and the outsides of the pieces) to give you something that would hold up to the abuse in sycamore and that increased distance will affect the magnets holding power.

However, I got to thinking of what you thought I meant and decided to give it a test (did I mention I love testing things?). I know that outside factors such as temperature affects the strength of magnets but I was wondering if the density of a material separating 2 magnets would really affect their strength. This was a really simple test with no quantitative measuring equipment though. No potential for harm = no fun. All I did was just take some different wood species at different thicknesses and see if the magnets would hold.

I first used balsa, mahagony, hard maple, and kingwood in 1/2" thicknesses with the same 3/8" diameter NIB magnets I used in the previous test. Couldn't tell a difference. I went up to 3/4" with the same woods. No difference between the wood species. I went up to 1". Aha! The balsa was holding (barely) but the kingwood wasn't nearly as much. So, I needed a more dense (or I think they are) wood to see if this was something. I used some snakewood and then some lignum vitae at 1" thickness. Yep, those didn't hold at all. There's not a huge difference but it's noticable. Yes, there's a big difference in the density of the balsa compared to the snakewood and lignum vitae and just the slightest difference in the hold of the magnets between those 2 extremes. I couldn't tell a difference between the mahogany, maple and kingwood which I'd call a medium to high density in what we normally work with. The snakewood and lignum vitae are what I'd call very high density woods.

Of course, these are highly unscientific tests. Way too many factors left unaccounted for. But, it was an interesting lunch break anyway. I'd like to hear if you've done your own tests and how they worked out.

- Andrew

Reply to
AHilton

I kind of kicked around this idea a bit more and I don't think I will go with the magnets for the S & P sets. Just not sure if they will "work" together - not physically work, but visually work. I like the idea that they fit together, but having them actually sticking together is a different idea.

We'll see.

Thanks Darren

Reply to
Darren

The conclusion is that you have *WAY* too much time on your hands!

Reply to
N00PY

Or you could start a new line for divorcing couples :)

Reply to
vmtw

I am interested in your question about magnets in turnings. I wanted to embed a magnet in a wood knocker and then have another in the base of a turned bowl. I reasoned that if the magnets repelled one another the knocker would knock against the sides of the bowl and I would have a kinectic bowl. I have tried it with little success. Either my bowl is too big or the magnets not strong enough. So goes another failed attempt at greatness.

Reply to
Lrens3

That day, absolutely. I enjoy testing things. Luckily, that's part of one of my day jobs. Not necessarily firing small magnets at skews but product testing and R&D, certainly.

- Andrew

Reply to
AHilton

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