Tiny Magnetic Table

[Corvus corax]

A tiny magnetic table for a Sherline mill. Uses HD magnets.

[Blade]

That is a cool little table, I have some magnetic coils off of auto a.c. pumps that I have thought about building a table out of because they run on twelve volts D.C. and are pretty strong.

[andyf]

Seems a rather complicated way to hold small ferrous workpieces. It would be simpler just to sit small items (ferrous or not) direct on the mill table and hold them with two stops and two low-profile clamps.  Or am I missing something?

Andy

[Corvus corax]

I doubt it's actually all that practical for milling anything. It's just a cute little design and nice workmanship.

[fixerup]

Thanks for taking the time to make the informative video. I really like the idea, especially when fly cutting very thin sheets of metal, washers  etc.......
Well done.
 
Phil

[ksor]

If the magnet can hold the object you'r machining, then - I think - YOU have to use the same amount of force to release the object from the table with the handle - right ?

If your object is as big as your magnetes I think it's hard to operate the handle - maybe I'm wrong - anyway tell me if so ! 

[John Stevenson]

No because the magnets work through a cam / lever system and they only have to move out of the way to break the flux.

One thing I did notice as I flicked thru the video with no sound, is that in the engaged position the lever was in the up position and down to release.
It really needs doing the other way so it can't get knocked down and release the part.

It is hard to mill with a mag table and you relay as much, if not more on the extra keepers to hold the work, mag tables are ideal for grinding but remember on thing, they work by having a closed path for the magnetic flux that's why you can't hold non ferrous materials and when you get down to shim thickness the holding power is very low as is the holding power of the keepers.

John S.

[ksor]

I don't know whata "cam / lever system" is - can you explain or do you have a link to an explanation ?

[ksor]

--> Thanks Meistro - I thought these on/off-magnets had a little more "magic" involved ...

I too have a lot of these magnets from scraped harddisks ... so maybe I should try make one of these magnetic tables too.

(For fun: Try drop one of the magnets through a vertical pipe of copper or aluminum and look through the pipe as it "falls" 
 the magnet sort of "floats" slowly downwards because of flux generated by eddy currents induced in the pipe material - it looks very stange, as though gravity is eliminated !)

The "factory-made" on/off magnets often has a surface with mixed layers (or rows) of iron and brass - is that a method of "directing" the flux or .. ?

[Corvus corax]

We had a couple of magnetic chucks at work, the favourite use for them was on the drilling machines. They held the vice perfectly in position and made set-up pretty quick.
The idea in the video could conceivably be used to make some useful indicator accessories.

[Bernd]

I only find one thing wrong with using magnets around hardened tooling. It eventualy picks up some magnetism and tiny bits of swarf collect on it.

Bernd