A simple and cheap swarf pickup tool

I noticed that you can buy magnetic swarf pickup tools online for anything from about £10 up to nearly £60. Being a parsimonious sort of guy - I couldn't see from their images why they cost so much. So I made one:

4 off 10mm dia x 10mm long neodymium magnets capable of 3.9kg lift = £8 (4 was minimum order at first4Magnets)

200mm length of 15mm OD FLOPLAST PE-X barrier pipe (general water piping) - had short length lying around - but about £1 per meter or less.I capped one end with a circular plastic cap super-glued on.

200mm coach-bolt - 35p from local shop.

I used a 30mm circle of rubber with 15mm hole in middle to act as a barrier along the pipe.

The magnet is so strong that the magnet and coach bolt thread end form a perfect bond. This combination is then just slipped into the tube. Swarf pickup is easy - withdrawing the coach bolt leaves most of the swarf behind and any left over is stopped by the rubber barrier - it then drops off. Another use is picking up any amount of ferrous objects - bolts, nuts, washers, etc - again withdrawing the coach bolt releases the objects.

So for a cost of £2-50 - or £10 if I make 4 and give three away as Christmas presents (cheapskate that I am) - I have a tool that does the job even if not so elegant.

Can you make a special one for me, I turn a lot of aluminium and it would be really useful.

Yes, but you will need to bathe your workshop in liquid nitrogen

Neil

Neil - rather an obtuse comment - can you explain? My simple answer to Norman is magnets don't attract non-ferrous metals - but his comment may have been tongue-in-cheek.

I just use a strong magnet inside a deep(ish) plastic bin/tub/etc. Nothing fancy.

Put a rare earth magnet on some bronze and see what happens.

Of course it was tongue in cheek, that was why I used the winking emoji.

Neil's reply was perfect, it needed no clarification. It made me do some research of my own. Have you tried dropping a neodymium magnet down the inside of a roll of aluminium foil? I have now, you learn something new every day.

I used to get students to drop a steel slug down a piece of copper pipe and catch it, as it exited, with the same hand. Then substitute a neo magnet for the steel slug and show how easy it was to catch it!

In simple terms, lines of magnetic field crossing a conductor induce a current which, in turn, produces a magnetic field which opposes that of the magnet (and defeats gravity a bit). B

asics of motors and generators.

Yes sorry guys - I don't recognise emoji's - something to do with lack of monitor peripheral vision - it's a technical term. Still prefer to use the ancient art of words to indicate emotions. Also my scientific journal editors would not allow such items without a glossary at the beginning of the paper to effectively define these terms so that other researchers could test my observations that had emoji's alongside.

Hi Colin. Great tool at decent cost saving.
Surprising how your helpful post can attract the muppets

Well done!

* Danny M *

Picking up non ferrous swarf, can it be done with eddy currents?

I have been thinking on the question posed by Norman Valentine

"Can you make a special one for me, I turn a lot of aluminium and it would be really useful."

I remembered I had seen a video of scrap metal being separated using this quite commonly used industrial process.

The following link points to various examples.

**LINK**

A good DIY example
**LINK**

OK so how do we make a hand tool that that uses the principle?

Some sort of moving magnetic field.
Or moving fields? maybe using electromagnets that pass the swarf along a tube? with a sort of peristaltic action. I guess it would be limited to nicely chip broken swarf not the annoying birds nests Aluminium in particular sometimes produces when turned.

I know this is a way out concept! A perfect test of the diverse skills that are available on this forum.

Any thoughts?

Regards
John

I think if you put a non magnetic conductor in an alternating magnetic field you get repulsion, not attraction.

Danny, I thought that it was a good idea but there is no harm in having a joke. I object to being called a muppet.

Repulsion or attraction does it matter? the main thing there a force, the question is how can we use that force to move the swarf particles?

How to use the force is the problem - attraction is easy to deal with but I can't see how you would easily operate a high speed magnetic rotor beneath a lathe or work-bench that could fling the non-ferrous metals in such a way that it didn't just create a mess somewhere else.

Hi Collin

I was thinking along the lines of a plastic tube probably double walled that had a series of electromagnets wound within it. If they were energized in order starting at the bottom, would small particles of material be propelled along the tube?

After I posted this question I did a little research: In the past I have seen a number of videos of DIY versions of so called rail guns, these however usually use sliding contacts and rather large capacitor banks to store enough energy to propel a projectile. Some appear to be quite dangerous. This is certainly not my intention here, I only want to move material at safe speeds.

I then stumbled upon what are called coilguns, these do not use sliding contacts they are more like a stack of solenoids see the link below.

**LINK**

From that link the following paragraph on non ferromagnetic projectiles

"Some designs have non-ferromagnetic projectiles, of materials such as aluminum or copper, with the armature of the projectile acting as an electromagnet with internal current induced by pulses of the acceleration coils." They are inducing eddy currents in the material.

So maybe there is a way to move non ferrous material slowly.

To be absolutely clear I have no interest and will not participate in any conversation about moving anything but swarf, waste or any other low speed material moving use.

I wonder if this is already done in industry?

Regards
J

My versions use a cheap extending "stick" magnet inside a piece of either 15 mm, or 22mm copper tube, with a thinned down copper or brass disc soldered onto the end.

Don't be like me and try to thin the end too much, otherwise you have to make the Mark 2 or even Mark 3 versions with thicker endplates!.

Rapid withdarwal causes MOST of the ferrous swarf to fall off, when it hits the external rubber ring. (Some of the very fine particles still adhere; possibly for the reasons posted above?)

Yes, very useful, saves my aged back from bending to retrieve dropped taps or hardware.

Pity that it doesn't work for brass or Ali!

Howard