The engine for the 1909 is progressing satisfactory and the time has come to re-charge the magnets for the magneto. It is generally accepted that each magnet should be able to hold an original Model T piston which weighs a little over two pounds. None of the 09 magnets passed the test.
In the past I have used some equipment that I lashed together, based on information in the MTFCA manuals. However this time, I choose to go a different route.
Locally in San Diego, we have a member who has spent many hours working on Model T magnets and developed some quite sophisticated equipment to re-charge T magnets. His previous results on later magnets are quite extraordinary and each magnet can be made to hold close to twenty pounds.
His equipment is a Ford magnet wound with two substantial coils and energized by a battery charger in the Engine Start mode. Each magnet is then energized three times for about three seconds. After charging all 16 magnets, each is checked for holding power, with weights added until the weight bucket breaks free of the magnet. The weight is then measured on a digital scale and recorded.
So I took my flywheel to his workshop and we charged all sixteen magnets and now each is able to hold between twelve to sixteen pounds. I should be good to go.
A comment on the on the methodology and results. The magnetizing coils were very carefully wound in layers with great care that each layer is absolutely uniform. The method of measuring the break-away weight is optimized with the weight suspended from a oiled, round bar to ensure excellent magnetic contact with each magnet and then the weights added with great care so as not to touch the weight bucket.
If anyone is interested in further details of the magnetizing process, Max can be contacted at treecemax AT yahoo.com , just change the AT to @.
Good heavens Tony! Average holding power using a ROUND shaft at 15.5 pounds? Wow! :-)
So will that make more amp / V's?
While I am for sure not an electrical person, I did read somewhere, maybe here, that you can have an initial charge that will hold X amount of weight but after a short while it will settle down to more normal amount, like 2 or 3 LBS weight holding.
Give it some time and recheck, maybe it will stay the same and maybe it will not. That was with the later style magnets, these early ones might be different.
Ether case, I like the idea and info.
Please, please tap each magnet after charging with the wooden handle end of a mallet. Surprisingly there may be several that break. How do I know? Been there, done that, of 16, 3 needed replacing due to becoming 2 piece magnets! The key words are "tap" and "wooden handle"
Yes, its been my experience with these early style magnets is that many are cracked.
We were concerned about magnet 13 which was weaker than the rest. We suspected a crack. We used a little colored iron dust placed over the magnet to see if there were any discontinuities, we found none.
These magnets are unlike the later style, which started life as a straight bar and bent. These appear to be cast.
Yesterday I wired the inner bolts with my usual twisted wire but the outer screws raised a problem. My wire appears to be slightly magnetic so I didn’t want to “bleed” magnetism from one magnet to the next, so I used copper wire for the outside screws.
Incidentally, when I received the flywheel, all 32 bolts were held by copper wire. I was not happy with this. There is no magnetism at the inner bolt so steel wire is better. JMHO
Instead of a gentle tap, I give each magnet a few good whacks against a vise or an anvil before charging. I don't like the idea of hitting a charged magnet with anything—wood, brass, whatever. I think it's the impact that demagnetizes, not the material used. That's why I put shims under the low magnets instead of hammering down the high ones.
The engineer who magnetized my magnet has provided a little more detail on possible failure modes.
Magnets that have been charged a year or so ago will be re-tested to refute the idea that they have lost charge.
Mishandling the heavy flywheel during and after removal from the engine is probably a cause of cracked magnets. A small bag of yellow Magnaflux crack detection powder has only been tried on the 1909 flywheel. However, the intent is to apply the powder and charge the magnet. Cracked Magnets Statistics Table, Ring Test Failures will be tested with the powder applied with a small artists brush.
If the bolt has been tightened to the flywheel and the restorer hit one leg at the end to squash the magneto support spool for increased space to the magneto coil, the resulting torque will stress the bend on the side, which is narrow. A crack could be started on the side of the bend. Consider that there are two 4 1/2 inch levers being twisted at the bolt. This magnifies the hammer-hit stress. Again, this is where the cracks starting up the sides at the inside of the bend.
DO NOT HAMMER OR APPLY FORCE TO LEVEL THE MAGNET. Due to mounting leverage involved, this is likely a cause of cracked magnets.
Leave the magnets on the flywheel.
I hadn't thought of magnets being cracked by pounding them down. That makes me prefer shims even more.