Knowing that flexible magnet material won't work, we move on to the hard sintered, nickel sealed supermagnets.

There are two types of supermagnet that are useable for the oil filter installation.  The first is the oldest, most expensive and least likely to get demagnetized by oil/temperature conditions, the samarium-cobalt hard sintered & nickle plated magnet.


www.duramag.com/magnet-materials/samarium-cobalt/default.asp

Now I wish I could find somebody that has a useable ring style magnet out of smararium-cobalt big enough for our intended use.  The properties of this material would be ideal for this particular use.  

I haven't found one yet the right size made of smararium-cobalt and I also think my wallet wouldn't care for the costs for such a magnet if I did find it  -- judging for what the small ones bring one big enough to go on the filter would be a real  "ouch" price-wise.

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Next, the "lesser" supermagnet material that IS more affordable and IS available in a ring form that we could use on our oil filter -- the neodymium hard sintered and nickel plated magnet.

http://www.duramag.com/magnet-materials/neodymium/default.asp

Now when you read about the temperature characteristics you willl see that these magnets can lose their strength due to elevated temperatures whereas the smaraium-cobalts do not.  

The key here is the word "elevated".  

After research at several magnet makers sites it turns out the neodymium hard sintered magnet can actually start out with a stronger  field strength than smaraium-cobalt and they will only begin to lose that extra strength at about the same temperature range that normal dino oil really begins to break down and blacken.  They will die completely at the same upper temperature range as synthetic motor oils -- cook your synthetic oil and totally cook your neodymium magnet at about the same time.

If you keep your oil at a more reasonable temperature range (less than 266 degrees F) then you get to keep both your dyno oil and your neodymium magnet with only mild weakening over time.  Our Savages live down in these more normal oil temperature ranges (150 - 200 degrees F).

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Physically fitting the magnet
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You need a center hole that is one inch (25mm) in diameter so the spring can go through it.  My spring measures 0.850" in outside diameter and some clearance is needed for alignment and motion.

(Did you know your oil filter can move a bit when your bike hits a bump?  It is designed that way ....)

Your outside diameter of the oil filter can is 2.365" so you could go slightly larger than that if you thought the cantilevered installation of the oil filter on the "O" ring spud (retained against road bumps and jars by the little spring's couple of pounds of clamping pressure and similar but flexible alignment force -- yeah, it would want to move around on you like Elvis's hips if you put a really big magnet on it)

Magnet thickness could be 0.250" or less.  My electronic caliper estimates the clearance space in front of the installed oil filter at 0.275" or thereabouts.

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www.supermagnetman.net/index.php?cPath=41&page=2
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Now, go here and see what is available for $10 or less.   This guy buys from China and he has the best prices on 40n and 50n hard sintered and nickel sealed neodymium magnets that I have seen on the web so far.

There are quite a few useable solutions shown here, you pick your experimental solution to suit your own ideas about "the best solution".   I picked the 50n (strongest field strength) and the lightest weight magnet thinking I didn't want the oil filter rock and rolling back & forth on the "O" ring every time I hit a bump or road seam.  

There are other choices -- I was tempted by the larger diameter rings and the thicker 1/4" rings, but I resisted temptation until I got some real world use on the smaller lighter magnet part number R1106

(I bought 2 of them so if it does lose its strength I'll have a spare for backup and i'll have a comparison match to find out if it really did get weaker in use).  

After all, the little R1106 ring magnet is still a whole lot bigger than the little spud sticking out of the magnetic oil plug and that little spud works like gangbusters even being as small as it is.  R1106 will do me until I know a lot more about it than I do right now, anyway.

You might want to wait until I find out what sort of screw ups come along with this new idea before ordering anything .....  I hate to say it but there might be some that crop up.

Good riding,

Oldfeller

Yeah, they do have that "Caution -- flesh mashing magnet" notation on the really big ones -- when they go to clamp up to solid steel you don't want a fold of skin in the way (or a finger bone either for that matter).

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Got another way to beat the "wobbling oil filter" problem due to excessive magnet weight -- fill up the empty space between the 1/4" thick magnet and the inside flat surface of the cover casting with something relatively soft like cork.

Go get a really large diameter magnet that is a quarter inch thick.  That thickness leaves you enough room for a post compression .035" to .045" thick cork gasket seated inside the circular flat section of the cover recess.  If you started with some stock cork gasket material  (.060" thick) it would settle the magnet fairly nicely in a motionless fashion when you tightened the cover down.  Stress would be between oil filter "O" ring and cork gasket/magnet.

Using this idea, you could step up to the R1250 2.5" diameter 1" ID hole 1/4" thick neodymium super magnet and match it with a rim of soft gasket material that is about .060" thick (standard soft unimpregnated cork gasket material would be dandy for this use, or you could spring for the stiffer rubber impregnated Permatex cork gasket material if you just had to have the good stuff).  

You might not want to fill up the entire surface, just a rim skimming lip around the outside of the casting recess, big enough to find the magnet, yet thin enough that not so much magnet/gasket junction is there to totally crush your filter or your "O" ring on the opposite side of the filter when you tighten it up.

The soft cork would take the circular indentation from the installed magnet and keep it from moving laterally as well as back & forth.  Your magnet and oil filter would be motionless and retained nice and square (no oil leakage at the "O" ring, which is a good thing).


www.supermagnetman.net/product_info.php?products_id=414

Simple, cheap and now you can spend $14 and get a really big powerful heavy super magnet that still won't be giving you any filter movement issues going over the bumps.

Oldfeller

Hey Oldfeller, any chance of pictures of this little adventure into supermagnets?

Would love to see a visual referance of what the mag looks like and what you are doing with it.

It isn't all that hard, take a replacement EMCO oil filter to fit your bike and put it in your hand.  Turn it so the hole side is down and the blank side is looking up at you.

See the recess where the clamping spring goes?  Put this magnet around that recess, it fits around the spring locating recess like it was intended to go there.  It gets in the way of nothing and does not weigh enough to cause the standard mounting system any problems.


www.supermagnetman.net/product_info.php?products_id=404

This is the $6.50 small magnet, it does a good enough job magnetically and it does not require doing anything different, just attach it and put your oil filter in as normal.



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Now this is the really large strong $14.00 magnet would require some reinforcement to the oil filter holding system because it is so durn big and heavy.  I also now think it would be somewhat of an overkill magnetically, but I do have one coming my way to play with.

 www.supermagnetman.net/product_info.php?products_id=414

Good points Oldfeller!  I didn't think about it attaching to the filter anyway.  And shielding most of the debris from the magnet by putting it inside the filter does have a great advantage  

The largest amount of fine metal mud that my oil drain plug magnet picked up between changes would fit on a thumbnail easily.

Spread that out over all the steel in the oil filter and I don't think you'd even really notice the coating thickness.

Crowd it all together and it could potentially stop up one (1) center flow cylinder perforation.  However, there are lots of these holes so if you split the mud up among them the build up wouldn't ever be flow limiting by any reasonable estimation.

You also have to remember that the metal stuff that the center perforations would see would be stuff that is fine enough to go through the oil filter paper.  Very very small particles, like on the order of 5-10 microns in size.  If particles this small  accumulated that thickly it would be like a very fine mobile "sludge" that would be moved aside by the oil flow pressure to move down into and reside on the inside of the perforated cylinder next to the hole.

I don't plan to let a filter stay in more than 2-3 oil changes, I'd be more afraid of the filter paper getting plugged up with clutch friction materials and blow by combustion trash than I would with the perforations getting clogged with metal particles.

I got the big magnet in Saturday afternoon but wasn't able to even open the shoe box sized square box until today.  

Lots of layered packaging was used with the magnet suspended in the exact center of the square box, but apparently they went for simple distance to control the field rather than using buffer plates of sheet metal (shipping the sheet metal would have cost too much?).  

It's strong compared to the previous magnet.  Using the opposite side of the oil filter (the hole side) I can put the oil filter an inch and a bit in the air up over the paper clip and yank the clip straight up in the air.  

20 times more powerful would be a way of guesstimating the extra field strength.

The R1250 magnet is a quarter of an inch thick and is slightly larger in diameter than the oil filter itself.  I cut four each 1/4" by 1/2" strips of cork material and put four mounting tabs on the bottom of the filter recess oriented in an up-down cross pattern.  The strips run across the bottom fillet radius of the casting recess so they locate the magnet radially and take also up the in-out excess clearance (by compression) all at the same time.  My filter material is .065" thick Permatex rubber-impregnated cork material and the resulting four tab "nest" lightly grips the magnet when it is installed in the cover.

I assembled everything to the engine and there did not seem to be any real complications to getting everything to seat.  I just moved the housing around a bit until all the parts aligned and I could finger seat it to within a "almost settled" condition with just finger force.   I was able to seat the 3 socket head screws using just finger pressure on the small end of the allen wrench, so I don't think anything is getting crushed.  The oil cover isn't leaking and all appears to be normal.

If I see signs of movement when I take it down at the next oil change I'll beef up the cork mounting tabs by adding four more tabs.  

Other than a propensity for the oil filter cover grabbing the allen wrench you can't tell there is anything different about the bike.   Shame that magnet trick with the stop light sensor buried under the pavement doesn't really work -- I'd be all set up.

Oldfeller

The small box shipping trick seemed to be based on having a small point source energize a broader flat piece of sheet metal from a short distance, diffusing the field by spreading it out over a larger area expressed by the flat sheet metal plate.  The second plate (buffered yet further out more with bubble wrap) catches the diffused broad field and diffuses it yet further.

The big box shipping trick works by pure distance, let the inverse square law take care of the field strength by not letting anything get within a half foot of it.   You can feel the magnet trying to get the allen wrench from 1 1/2 inches away right through the aluminum case, so six inches or so might be enough to protect electronics in shipment.  Or not -- depending on how sensitive the electronics might be.

They say magnets have healing properties.  If so my right foot will likely be right healthy from now on.  Hmmmmm,  I wonder if I'll feel it when I ride to work wearing my work shoes (steel toe)?

Oldfeller