Magneto file

[clivelParticipant @clivel]

Years back I remember cleaning the contacts of a large relay with a "magneto file". A flat file about 6" long including the handle which was integral with the blade – both being formed from a single piece of metal.
Recently while examining some burnt relay contacts I was reminded of the file and wondered if such a thing actually existed or if it was just my memory playing tricks.

A google such was surprisingly unhelpful. Only two hits on an actual tool, one from RS components (now listed as discontinued) and another from an Australian company called Boker. There were however dozens of hits on a comic-book character named Magneto
I find it somewhat depressing that a piece of engineering equipment, probably around from the dawn of flight, can be so quickly displaced by an element of common culture that I hadn't even heard of.

I was wondering if these tools perhaps had another name, or if they were just not widely known?

Clive

[clivelParticipant @clivel]

[John ReeseParticipant @johnreese12848]

It is the same or similar to a distributor point file. Try searching under that name.

[Tim StevensParticipant @timstevens64731]

Yes, there were such things as magneto files. They date from the early days of motoring, when the contact-breaker (and not just for magnetos) was faced with platinum. As erosion damaged the surfaces, they could be 'dressed' back to shape using a light hammer and skill, or filed away with the appropriately named tool. As soon as tungsten came into use, the files ceased to be useful for this job, as the tungsten was too hard. But makers carried on using them, and selling them to innocent motorists. Just as they do, still, with small brass brushes 'to clean sparking plugs'. No-one tells the punter that this is not a good idea as modern (post WWII) plugs have hard alumina-ceramic insulators, which can become coated with brass particles – which then short out the HT …

If you can find one that has not been used on tungsten, a magneto file is a handy tool in the workshop. But not on a magneto, please.

Regards, Tim

[SillyOldDufferModerator @sillyoldduffer]

Posted by clivel on 03/04/2017 21:15:40:

…

I find it somewhat depressing that a piece of engineering equipment, probably around from the dawn of flight, can be so quickly displaced by an element of common culture that I hadn't even heard of.

…

Clive

Depends where you start from Clive, the root lies in Classical Greek culture, not engineering.

Magneto, comes from Magnet, which in turn is named from Magnesia (a district in Greece where the Magnetes lived). The Magnetes were named for Magnes who was the son of Zeus and Thyia.

Dave

[Adrian GilesParticipant @adriangiles39248]

They were about, certainly, I had some when I was much younger and mucking about with cars and bikes that needed them. But with modern vehicles that you can't do much with, use of them has died out. Last time i needed to clean contacts, I used emery cloth. Could always use needle files as an alternative.

[V8EngParticipant @v8eng]

No doubt Magneto Files went the same way as Magneto Spanner sets = a set of of about 5 (I think) small single ended O/E spanners all hinged together at one end with a single feeler gauge blade on one side of the spanner set and a small flat blade (screwdriver?) on the other side.

Think I have got a set tucked away somewhere (maybe).

Edited By V8Eng on 03/04/2017 21:49:10

[Neil WyattModerator @neilwyatt]

Magnetos are alive and well on most lawnmowers/chainsaws/strimmers…

Neil

[davebParticipant @daveb17630]

Posted by V8Eng on 03/04/2017 21:42:03:

No doubt Magneto Files went the same way as Magneto Spanner sets = a set of of about 5 (I think) small single ended O/E spanners all hinged together at one end with a single feeler gauge blade on one side of the spanner set and a small flat blade (screwdriver?) on the other side.

I have a Terry's set. Consists of a few spanners, a feeler gauge and a file/screwdriver all riveted together at one end. It was a very useful part of the bike toolkit as was the thingy to hold the chain together while I laid in a puddle trying to fit a split link in the dark. Dave

[EmgeeParticipant @emgee]

A double sided diamond file would be a modern equivalent.

Emgee

[V8EngParticipant @v8eng]

Posted by daveb on 03/04/2017 22:03:28:

Posted by V8Eng on 03/04/2017 21:42:03:

No doubt Magneto Files went the same way as Magneto Spanner sets = a set of of about 5 (I think) small single ended O/E spanners all hinged together at one end with a single feeler gauge blade on one side of the spanner set and a small flat blade (screwdriver?) on the other side.

I have a Terry's set. Consists of a few spanners, a feeler gauge and a file/screwdriver all riveted together at one end. It was a very useful part of the bike toolkit as was the thingy to hold the chain together while I laid in a puddle trying to fit a split link in the dark. Dave

 

Yes and that tool to hold the chain links from the back while a threaded rod pushed the chain rivet through from the front. Used for adding or removing links, loaned mine to a friend, never got it back.

Edited By V8Eng on 03/04/2017 22:25:03

Edited By V8Eng on 03/04/2017 22:26:03

[Bob StevensonParticipant @bobstevenson13909]

I still use my magneto files…….because they are flat they are excellent for filing both sides of a butt joint at the same time to make a perfect joint for silver soldering, particularly when making clock spring barrels…….once the barrel is formed hold the joint with the magneto file in situ and file while squeezing both sides agains tthe file……test the edges frequently against a light source and once the joint shows no gaps it's ready to solder.

……I also use a small locksmiths warding file (for making the wards of a lock) which is also a flat file but coarser than a magneto file………warding files are getting difficult to find as well now.

[duncan webster 1Participant @duncanwebster1]

Posted by Tim Stevens on 03/04/2017 21:28:00:

Yes, there were such things as magneto files. They date from the early days of motoring, when the contact-breaker (and not just for magnetos) was faced with platinum. As erosion damaged the surfaces, they could be 'dressed' back to shape using a light hammer and skill, or filed away with the appropriately named tool. As soon as tungsten came into use, the files ceased to be useful for this job, as the tungsten was too hard. But makers carried on using them, and selling them to innocent motorists. Just as they do, still, with small brass brushes 'to clean sparking plugs'. No-one tells the punter that this is not a good idea as modern (post WWII) plugs have hard alumina-ceramic insulators, which can become coated with brass particles – which then short out the HT …

If you can find one that has not been used on tungsten, a magneto file is a handy tool in the workshop. But not on a magneto, please.

Regards, Tim

My 1968 Vauxhall Viva used to transfer material from one contact to the other. After 3000 miles, one would have pointy bit, the other would have a depression. If you left it alone it would develop a misfire. Take them out, grind off the pointy bit on the bench grinder, put them back. After 6000, the depression was a hole, so replace the whole assembly. I tried changing the capacitor, no difference. Parts shops had racks of points, I never understood why manufacturers couldn't agree a standard design. And then we look back with rose tinted glasses. Yes you can't just wade in with modern cars, but they very rareley go wrong in my experience, and I run them to 160,000 miles before even thinking of changing.

Edited By duncan webster on 03/04/2017 23:16:36

[Anonymous]

Posted by Neil Wyatt on 03/04/2017 21:53:43:

Magnetos are alive and well on most lawnmowers/chainsaws/strimmers…

And on most piston engine aircraft.

Andrew

[Michael GilliganParticipant @michaelgilligan61133]

Posted by clivel on 03/04/2017 21:15:40:

A google such was surprisingly unhelpful.

.

Clive,

Beware Google's nasty habit of replacing what you typed with what it "knows" you meant.

.

You sometimes need to tell it who's Boss !!

MichaelG.

.

P.S. [just for completeness] A Magnetophile is someone who loves Magnetos 

Edited By Michael Gilligan on 04/04/2017 00:26:12

[warwick wilton 1Participant @warwickwilton1]

may be a diamond file will do and you can do your nails after?

Ww

[Dinosaur EngineerParticipant @dinosaurengineer]

The best type of contact breaker had a hole in the middle of the contacts. This prevented a "pip" and hollow from forming in the middle of the contact. Smaller "pips" and hollows formed around the periphery of the contacts and thus the contacts lasted much longer as the pips/hollows followed around the circular path instead of just forming in the middle You couldn't just keep filing the pips down because by this time the "heel" of the cam follower also became severely worn and the dwell angle became compromised..

[JasonBModerator @jasonb]

Put "contact points file" into your favorite search engine and you will find plnty, looks like Nicholson still do them.

[Ian S CParticipant @iansc]

The first mag file that I knew of was one that my Grandpa had, it was about 6" long, and had a pointed end, same as a nail file has, he said it was given to him by an aeroplane mechanic when he was visiting an aerodrome in England during WW1.

Mag/point files are not for magnetos, or relay points. For relays the best thing to start with is a thin strip of plain paper pulled through the closed contacts. For Tungsten points, the scrap bin.

My mag file has a blade about 4" long by 5/16" wide, and 3/64" thick with safe edges, and a handle 1 1/2" long. They seem to be a bit harder than a normal engineers file, They do break if you get too enthusiatic.

Ian S C

[John FlackParticipant @johnflack59079]

At the risk of answering the original question I was informed that the file mentioned was a BAR file, a term that now has a more bewildering use. The length of a magneto file odd as you can only use the first mms. in situ or dismantle part of the timing set up. Friends used to borrow mine to redo slot in screws SLOTCUTTING file?

[MikeParticipant @mike89748]

Whenever I've got a job like that to do I use one of my wife's very slim diamond nail files. I don't think she reads this forum, but if I suddenly disappear off the scene you will know why………….

[Howard LewisParticipant @howardlewis46836]

Contacts on Magnetos and distributors (and presumably Relays) can be cleaned by folding some WetnDry paper, to make a narrow double sided tape.

Running this to and fro through the closed contacts will clean them, followed by clean paper to remove any debris.

Ford's own points used on their later distributors used a tubular contact for one side, which tended to reduce the "pip" effect.

Howard

[Martin KyteParticipant @martinkyte99762]

Similar story with com files (com as in commutator) google it and you get DEC executable batch file.

You can however still buy the things.

regards Martin

[V8EngParticipant @v8eng]

Posted by Mike on 04/04/2017 15:22:20:

Whenever I've got a job like that to do I use one of my wife's very slim diamond nail files. I don't think she reads this forum, but if I suddenly disappear off the scene you will know why………….

Yes be careful if she finds out because, if they are anything like my Wife's Nail files they have a sharp pointy end!

Edited By V8Eng on 04/04/2017 16:29:57

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Flack on 04/04/2017 13:57:17:

At the risk of answering the original question I was informed that the file mentioned was a BAR file, a term that now has a more bewildering use.

.

I've not heard of a BAR file, John … but I wonder if the name has the same origin a a barrette file [which is one with a 'safe' back]. … Maybe the barrette was seen as 'half' of a bar

MichaelG.

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