Post by thread:[EE] Tool Demagetizer

I seem to regularly have some tool or another which somehow becomes magnetized - rendering it either annoying (ever tried to trim leads with a magnetized set of cutters?) or just plain useless (magnetized tweezers used to place parts anyone?). I've tried a "passive" tool magnetizer/demagnetizer with no luck - it seems to leave plenty of residual magnetism, and maybe even makes it worse. I know that I can build a TV style degauss unit out of a big (meaning long and also large around) coil of magnet wire attached to an AC plug, but the plans I've found of course require lots of magnet wire, and are definately not designed for tool demagnetizing. I'd try winding a similar amount of wire onto a smaller form, but creating a unknown inductance and plugging it into an AC wall outlet scares me for obvious reasons. I've also given some thought of making one and putting it in series with a 100W indandescent "current limiter and light producer", but that isn't really what I want. So, to ask my questions: 1) Has anyone had luck with any of the "passive" demagnetizers, meaning that a specific type seems to remove all traces of magnetism from a given tool? 2) How about some of the commerical "active" demagetizers. Seems like there are a few that are around $100 or so, but I don't want to buy 2-3 to find one which works. 3) Finally, are there any kits/plans available to build your own ... or does someone have one they built which works? And perhaps related - let's assume I build one, does anyone have an idea of the inductance and/or DC resistance I would need to not pop the breaker and/or cause glowing wire? Let's assume US 120V 60Hz. Thanks. -forrest

> (ever tried to trim leads with > a magnetized set of cutters?) or just plain useless (magnetized tweezers > used to place parts anyone?). I have one cutter that somehow became magnetised - and I love it! No more wire ends on the floor to hurt my bare feet! But I can't help you with demagnetizing. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: http://www.voti.nl consultancy, development, PICmicro products docent Hogeschool van Utrecht: http://www.voti.nl/hvu

Wouter van Ooijen wrote: > I have one cutter that somehow became magnetised - and I love it! No > more wire ends on the floor to hurt my bare feet! Actually the magetized cutter got moved to the R&D "facility" (aka home workshop) where I agree that a magnetized cutter is not necessarily a bad thing. However, it *does* get annoying when I am in production mode and have to stop every few leads and wipe the tool off... I'd rather them drop on the table below the cutter (I use cutters with cut-lead retention so they stick in the tool until the cutting pressure is released instead of flying across the room upon cutting). -forrest

Wouter van Ooijen wrote: > > (ever tried to trim leads with > >> a magnetized set of cutters?) or just plain useless (magnetized tweezers >> used to place parts anyone?). >> > > I have one cutter that somehow became magnetised - and I love it! No > more wire ends on the floor to hurt my bare feet! > > But I can't help you with demagnetizing. > > Wouter van Ooijen > > -- ------------------------------------------- > Van Ooijen Technische Informatica: http://www.voti.nl > consultancy, development, PICmicro products > docent Hogeschool van Utrecht: http://www.voti.nl/hvu > What wire are you cutting? I was under the impression that copper wasn't ferromagnetic IE a magnet doesn't exert a force on it (neglecting electrical effects)

----- Original Message ----- From: "Forrest Christian" <spam_OUTforrestcTakeThisOuTimach.com> To: "Microcontroller discussion list - Public." <.....piclistKILLspam@spam@mit.edu> Sent: Thursday, April 03, 2008 2:56 AM Subject: [EE] Tool Demagetizer {Quote hidden}>I seem to regularly have some tool or another which somehow becomes > magnetized - rendering it either annoying (ever tried to trim leads with > a magnetized set of cutters?) or just plain useless (magnetized tweezers > used to place parts anyone?). > > I've tried a "passive" tool magnetizer/demagnetizer with no luck - it > seems to leave plenty of residual magnetism, and maybe even makes it > worse. > > I know that I can build a TV style degauss unit out of a big (meaning > long and also large around) coil of magnet wire attached to an AC plug, > but the plans I've found of course require lots of magnet wire, and are > definately not designed for tool demagnetizing. I'd try winding a > similar amount of wire onto a smaller form, but creating a unknown > inductance and plugging it into an AC wall outlet scares me for obvious > reasons. I've also given some thought of making one and putting it in > series with a 100W indandescent "current limiter and light producer", > but that isn't really what I want. > > So, to ask my questions: > > 1) Has anyone had luck with any of the "passive" demagnetizers, meaning > that a specific type seems to remove all traces of magnetism from a > given tool? > > 2) How about some of the commerical "active" demagetizers. Seems like > there are a few that are around $100 or so, but I don't want to buy 2-3 > to find one which works. > > 3) Finally, are there any kits/plans available to build your own ... or > does someone have one they built which works? And perhaps related - > let's assume I build one, does anyone have an idea of the inductance > and/or DC resistance I would need to not pop the breaker and/or cause > glowing wire? Let's assume US 120V 60Hz. > > Thanks. > > -forrest > > > -- Possibly one of the links available here may help: http://www.thomasnet.com/products/demagnetizers-22000608-1.html Good luck, Richard

I have a passive (non-powered) permanent magnet type demagnetizer that has a rectangular hole for magnetizing, and a "D" shaped hole for demagnetizing . It works well with screwdriver blades, and the hole is large enough for thin pliers or side cutters, but haven't had the oportunity to try those. The link below is for a similar, mine doesn't have the steps on the hole: www.magnetsource.com/Consumer%20Pages/Mag_Demag.html Jake Anderson wrote: {Quote hidden}> Wouter van Ooijen wrote: > >> > (ever tried to trim leads with >> >> >>> a magnetized set of cutters?) or just plain useless (magnetized tweezers >>> used to place parts anyone?). >>> >>> >> I have one cutter that somehow became magnetised - and I love it! No >> more wire ends on the floor to hurt my bare feet! >> >> But I can't help you with demagnetizing. >> >> Wouter van Ooijen >> >> -- ------------------------------------------- >> Van Ooijen Technische Informatica: http://www.voti.nl >> consultancy, development, PICmicro products >> docent Hogeschool van Utrecht: http://www.voti.nl/hvu >> >> > What wire are you cutting? I was under the impression that copper wasn't > ferromagnetic IE a magnet doesn't exert a force on it (neglecting > electrical effects) >

>3) Finally, are there any kits/plans available to build your own ... >or does someone have one they built which works? And perhaps related - >let's assume I build one, does anyone have an idea of the inductance >and/or DC resistance I would need to not pop the breaker and/or cause >glowing wire? Let's assume US 120V 60Hz. My father made his own. He had a transformer (had about 1 sq inch core cross section IIRC) from which he removed all the E & I cores so it was an open winding, then connected it to a model toy power transformer that had an AC output of around 16V. Worked very well, move magnetised tool into centre of winding with power on coil, and withdraw slowly, taking about 5 seconds to move it a couple of feet from the coil, and then turn power off.

>>> What wire are you cutting? I was under the impression >>> that copper >>> wasn't ferromagnetic >> Copper isn't, but many component leadouts are >> nickel-plated and >> a few have steel wire under that > ahh got ya, forgot about that lol. Most small leaded components can be picked up with a magnet. It's never obvious what isn't going to be. AFAIR diodes like 1N400x and 1N581x are less likely than most to be 'magnetic'. Russell

> 3) Finally, are there any kits/plans available to build your own ... or > does someone have one they built which works? And perhaps related - > let's assume I build one, does anyone have an idea of the inductance > and/or DC resistance I would need to not pop the breaker and/or cause > glowing wire? Let's assume US 120V 60Hz. Just a thought and I've never tried it, but what about heating the tool, or impact? I know that sufficient heating, or a good stiff blow (say a 10 foot fall to a concrete floor) can ruin a perfectly good permanent magnet. Could the same thing apply here? I seem to recall the junior high science demonstration involving an iron magnet placed on a stove burner or similar. Not glowing hot, but pretty darn warm. Mike H.

IIRC the "Curie Point" of a material is the temp at which ferromagnetic properties go away... Jack On 4/3/08, Mike Hord <mike.hordKILLspamgmail.com> wrote: {Quote hidden}> > 3) Finally, are there any kits/plans available to build your own ... or > > does someone have one they built which works? And perhaps related - > > let's assume I build one, does anyone have an idea of the inductance > > and/or DC resistance I would need to not pop the breaker and/or cause > > glowing wire? Let's assume US 120V 60Hz. > > Just a thought and I've never tried it, but what about heating the tool, or > impact? > > I know that sufficient heating, or a good stiff blow (say a 10 foot fall to > a > concrete floor) can ruin a perfectly good permanent magnet. Could the > same thing apply here? > > I seem to recall the junior high science demonstration involving an iron > magnet placed on a stove burner or similar. Not glowing hot, but pretty > darn warm. > > Mike H. > -

Quoting Jake Anderson <.....jakeKILLspam.....vapourforge.com>: > Jinx wrote: >>> What wire are you cutting? I was under the impression that copper >>> wasn't ferromagnetic >>> >> >> Copper isn't, but many component leadouts are nickel-plated and >> a few have steel wire under that >> >> > ahh got ya, forgot about that lol. > > -- I saw a home-made one wot consisted of the stator of a dismantled 1/4HP(?) motor in series with a fairly hefty (maybe 500-750W) strip heater. Seemed to work okay, and could be build for almost nothing with scrap parts. A few 100W incandescent light bulbs in parallel would work in place of the heater (this is not a good place to substitute CF bulbs). ;-) Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" EraseMEs...spam_OUTTakeThisOuTinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

that's a very smart analog close-loop temperature control. Do you happen to know which company make these tools? Funny N. Au Group Electronics, New Bedford, MA, http://www.AuElectronics.selfip.com ----- Original Message ---- From: Alan B. Pearce <A.B.Pearcespam_OUTrl.ac.uk> To: Microcontroller discussion list - Public. <@spam@piclistKILLspammit.edu> Sent: Thursday, April 3, 2008 9:55:33 AM Subject: Re: [EE] Tool Demagetizer >IIRC the "Curie Point" of a material is the temp at which ferromagnetic >properties go away... But the magnetism comes back when the temperature drops below the Curie point. A number of soldering irons control their tip temperature this way.

On Thu, Apr 3, 2008 at 10:31 AM, Funny NYPD <RemoveMEfunnynypdTakeThisOuTyahoo.com> wrote: > that's a very smart analog close-loop temperature control. > Do you happen to know which company make these tools? Weller and others. I use a Metcal, which pumps RF energy to the handpiece, and when the tip comes up to temperature, it stops absorbing RF. More of a linear mechanism. I can work on SMD devices, and shield cans with the same tip.

> Just a thought and I've never tried it, but what about > heating the tool, or > impact? Heating is very liable to affect metal "temper". Non magnetised non-cutters may result. Repeated percussion below damage range should work BUT the various electromagnetic methods that have been mentioned should be fine. Generate a strongish AC field, present the tool to it and then move it slowly away. The field needs to be strong enough to adequately overcome the coercivity (natural cussedness, magnetic stay-puttedness) of the material and will vary with tool material. Soft irons are easily changed. Some stainless steels and similar may be 'rather difficult' but these are also less liable to have been magnetised initially. An opened transformer core fed from a low voltage transformer should be adequate for most objects. Variac on primary of driving transformer is useful. No variac ? - light bulbs in series with secondary and opened core will do. Experiment to ghet desired brightness as an indication of current flow. Very dark bulb is much lower R than when even moderately orange so a degree of variable current limiting is provided. R on = Vrated^2/Watts_rated. Cold R is 10+ times lower. If you have a variac you can keep the tool still and wind down the voltage. TVs and monitors have a degaussing feature built in. May not have enough 'grunt' but the thump you get when some monitors debauss suggests some serious amp turns. AFAIK many of these use only a PTC and a coil and mains so mayhaps gutting out this part from a dead monitor may suffice. The degauss coil could be wound into a smaller coil of coils to get more amp turns. YMMV.Dont try this at home. All care and no responsibility. Do not spindle fold punch mutilate staple or bend. You have the right to remain si ... . Russell

Live & learn - That's pretty neat. Jack On 4/3/08, David VanHorn <TakeThisOuTmicrobrixEraseMEspam_OUTgmail.com> wrote: > On Thu, Apr 3, 2008 at 10:31 AM, Funny NYPD <RemoveMEfunnynypdTakeThisOuTyahoo.com> wrote: > > that's a very smart analog close-loop temperature control. > > Do you happen to know which company make these tools? > > Weller and others. > > I use a Metcal, which pumps RF energy to the handpiece, and when the > tip comes up to temperature, it stops absorbing RF. > More of a linear mechanism. I can work on SMD devices, and shield > cans with the same tip. > -

On Thu, 03 Apr 2008 00:56:06 -0600, "Forrest Christian" <forrestcEraseME.....imach.com> said: > 3) Finally, are there any kits/plans available to build your own ... or > does someone have one they built which works? And perhaps related - > let's assume I build one, does anyone have an idea of the inductance > and/or DC resistance I would need to not pop the breaker and/or cause > glowing wire? Let's assume US 120V 60Hz. Get an old shaded pole motor and pull the moving parts off, it will work fine. Those are the types of motors used in bathroom exhaust fans. The trick is to stroke the tool on the demagnetizer, and the final pull off needs to be smooth. Re-reading that last sentence makes me think I might have a future writing porn :) Cheerful regards, Bob -- http://www.fastmail.fm - Send your email first class

A magnetic tape bulk eraser works very well for this. These can be had for not much money these days - most broadcasters are dumping anything to do with magnetic tape. eBay is a good place to look, as are any local radio and TV broadcast facilities. FWIW - the local broadcast engineers are great people to get to know. I have at least 2 units - one from Nortronics and another from Hammond. The Hammond table-top units (foot-switch controlled) are just fabulous - that's what we used to use when erasing carts prior to recording new material onto them. Proper technique is really important: turn the demanetiser on, bring the tool close in and touching, then slowly start moving the tool in a circular motion. Slowly make the circles wider as you are moving the tool further away from the demagnetiser. You can turn the demagnetiser off when the tool is about a full arms-length away from it. Total demagnetising time takes 10 - 15 seconds if you do it properly. dwayne At 12:56 AM 4/3/2008, Forrest Christian wrote: >2) How about some of the commerical "active" demagetizers. Seems like >there are a few that are around $100 or so, but I don't want to buy 2-3 >to find one which works. -- Dwayne Reid <EraseMEdwaynerplanet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax http://www.trinity-electronics.com Custom Electronics Design and Manufacturing

Quoting Apptech <RemoveMEapptechEraseMEEraseMEparadise.net.nz>: >>>> What wire are you cutting? I was under the impression >>>> that copper >>>> wasn't ferromagnetic > >>> Copper isn't, but many component leadouts are >>> nickel-plated and >>> a few have steel wire under that > >> ahh got ya, forgot about that lol. > > Most small leaded components can be picked up with a magnet. > It's never obvious what isn't going to be. AFAIR diodes like > 1N400x and 1N581x are less likely than most to be > 'magnetic'. > > Russell I'd expect power components such as rectifiers to be more likely to have copper than steel leads since the thermal conductivity of Cu is so much higher than that of steel (almost an order of magnitude). Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" RemoveMEs...spam_OUTKILLspaminterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

Get an old fashioned transformer based soldering gun. Bend the wire tip into a loop. Stick the tool in the loop, turn on the gun, while keeping the tool centered in the loop slowly withdraw it at least 12" before turning off the gun. Done. The soldering tip/loop is the 1 or 2 turn secondary of a transformer. The very heavy current in the loop creates a strong alternating magnetic field. Genuine Weller at big box store for $27: http://www.lowes.com/lowes/lkn?action=productDetail&productId=97541-000000273-8200PK Cheap import for $10: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=4328 Don

> The trick is to stroke the tool on the demagnetizer, and the final > pull off needs to be smooth That's how I used to demagnetise my reel-to-reel heads. You'd keep the coil energised and pull away slowly to a couple of feet > Re-reading that last sentence makes me think I might have a > future writing porn :) I got a flyer from RS this morning advertising "Half-Price Strippers !!" Yowza !!! Imagine my disappointment to find it was just a fire-sale clearance of lap dancers and quasi-working girls. Think I'd rather lease ......

On 03/04/2008, Jinx <RemoveMEjoecolquittTakeThisOuTspamclear.net.nz> wrote: > I got a flyer from RS this morning advertising "Half-Price Strippers !!" > > Yowza !!! > > Imagine my disappointment to find it was just a fire-sale clearance > of lap dancers and quasi-working girls. Think I'd rather lease ...... Well, as Matt said in the logic analyser thread, "buy the very best you can afford right now that meets all your current needs" :-) Dan

Now that's an elegant solution... I've got a couple of those floating around which I can use... -forrest Don Lewis wrote: {Quote hidden}> Get an old fashioned transformer based soldering gun. Bend the wire > tip into a loop. Stick the tool in the loop, turn on the gun, while keeping > the tool centered in the loop slowly withdraw it at least 12" before turning > off the gun. Done. > > The soldering tip/loop is the 1 or 2 turn secondary of a transformer. The very > heavy current in the loop creates a strong alternating magnetic field. > > Genuine Weller at big box store for $27: > > http://www.lowes.com/lowes/lkn?action=productDetail&productId=97541-000000273-8200PK > > Cheap import for $10: > > http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=4328 > > Don > > > > > > > > > >

> Get an old fashioned transformer based soldering gun. > Bend the wire > tip into a loop. Stick the tool in the loop, turn on the > gun, while keeping > the tool centered in the loop slowly withdraw it at least > 12" before turning > off the gun. Done. > > The soldering tip/loop is the 1 or 2 turn secondary of a > transformer. The very > heavy current in the loop creates a strong alternating > magnetic field. A "poker work" transformer might do equally well. These a transformer used to heat a resistive element to create charred "etching" on wood etc for decorative purposes. There are or were some 'quick heat' soldering irons that use(d) a very low resistance element and no temperature control - you 'blip' the switch (sometimes a ring on the barrel) for as long as experience tells you is needed and then solder using the tip's thermal mass. Worked remarkably well for heavy jobs that could stand not having temperature control. You knew that you had overdone it when the tip distorted under overheating and fell out. I suspect that their transformers would also be up to this task. The brand name Scope is suggested by my hindbrain. Russell

> You been wandering along K-Road again Jinx .... claiming to go to > that Dick Smith store along there ??? Haha, Trannie HQ Oh yeah, right. Dick Smith. What are you like eh ? Yesterday I was pricing USB external drives. I rang DSE in New Lynn as they'd had HDD specials recently "I'm afraid we've got only two in stock, both WD 320GB" "OK, how much ?" "Well, they aren't for sale" "Oh" "One is a shelf model, and it's got bits missing. The other one is a customer return. And it's got bits missing" "You know, I spoke to your manager once about taking stuff back that was incomplete. Like the pile of cheap VCRs and DVDs with no remotes or power cords. Looks like you're stuck with a couple of hard drives too now" "Yeah, guess so. Oh well" "OK, thanks anyway, bye" And I went to see my little Chinese man who beat DSE by a mile anyway

> >I got a flyer from RS this morning advertising > >"Half-Price Strippers !!" >>Yowza !!! >>Imagine my disappointment to find it was just a fire-sale >>clearance >>of lap dancers and quasi-working girls. Think I'd rather >>lease ...... > You been wandering along K-Road again Jinx .... claiming > to go to that Dick > Smith store along there ??? Each area has it's specialists and the streets of K Road are no exception. In the last phase of my corporate incarnation, now almost only a dim memory ago, I used to work in a large building adjacent to the above mentioned and inferred places. I would often leave late at night and drive through the streets behind Dick Smiths' as a short cut to the motorway. Quite an education. At second glance it was evident enough that a majority of the people standing under the street lights on the corners were not quite what one may have expected at first glance. One could make an educated guess re the minority. Probably not quite what the writer of the above passage was thinking of when he wrote it. Russell

>> You been wandering along K-Road again Jinx .... claiming >> to go to that Dick >> Smith store along there ??? > >Each area has it's specialists and the streets of K Road are >no exception. >In the last phase of my corporate incarnation, now almost >only a dim memory ago, I used to work in a large building >adjacent to the above mentioned and inferred places. I would >often leave late at night and drive through the streets >behind Dick Smiths' as a short cut to the motorway. Quite an >education. At second glance it was evident enough that a >majority of the people standing under the street lights on >the corners were not quite what one may have expected at >first glance. One could make an educated guess re the >minority. Probably not quite what the writer of the above >passage was thinking of when he wrote it. You seemed to have followed my tracks ... when on night time callout I sometimes went that exact same track if I had to go to the office first (in upper Queen St) to pick up some spares or equipment. Sometimes at the intersection behind DSE one could almost have the car mobbed by girls. The other trick was to have dinner in the revolving restaurant on the top of the Telecom building, you could see the girls setting themselves out on the street corners as the evening went on. If anyone has the book on K-Road (cannot remember its title at the present) that was written by a rubbish man that did the bin clearing in that area, there is a photo of my company car in front of the building that had an enormous (for the size of the building) sign of a naked lady. I had parked there to go to the bank about 3 doors down, at lunch time - yeah, that is my story, and I'm sticking to it ... ;)

--- Jinx <EraseMEjoecolquittspamspamBeGoneclear.net.nz> wrote: > > Well, as Matt said in the logic analyser thread, "buy the very best > > you can afford right now that meets all your current needs" :-) Hah, well I just use a stator out of a busted old AC electric drill, with the rotor removed, obviously. Dip the tool - screwdriver, tweezers or whatever - into the empty stator cavity with the power turned on and voila, demagnetised. Best I can afford right now. :| Debbie Get the name you always wanted with the new y7mail email address. http://www.yahoo7.com.au/y7mail