Recharging magnets out of the engine

[Dave Young]

I’ve got the flywheel off of the engine that I’m currently redoing. The mag worked fine in this car before pulling the engine out, but I want to give the magnets a boost while it’s all apart. I don’t want to remove the magnets from the flywheel and have seen, in the “TRANSMISSION” book, a photo of an assembled flywheel sitting on a metal grease drum, magnets up, field coil ring sitting on the magnets, and a battery charger. No details are given as to the procedure of “zapping”. I’ve done it before, in the car, and been successful. Never did it this way before.

Does the coil ring just sit directly on the magnet clamps and then get rotated a bit until they stick together ?

Positive lead hooked to the mag post contact?

Battery Charger or some 8D 12 volt batteries? I’ve got all kinds of chargers and batteries at my disposal.

Voltage?

Thanks and Happy New Year to all.

[Art M]

I recommend removing the magnets from the flywheel, examine everything, and at least install new brass holddown screws. These screws have a tendency to break.

Art Mirtes

[BobShirleyAtlantaTx]

When you reassemble, a few thimbles made from brass makes balancing the assembly easy.

[jab35]

David: Most people 'zap' the mag ring with a DC welder. And it will require a prybar to separate the flywheel and mag ring afterward. A lot has been posted on this subject including many photos. Good luck with your project, jb

[John kuehn]

Have the magnets ever been off the flywheel since you’ve had it? Maybe the magnets have been gone through before but if they haven’t been taken off now would be the time to do it and the spools checked and magnet screws replaced. Just my opinion of course and you know the condition better than I do. Good luck.

[Steve Jelf]

I agree with Art. As long as you have the flywheel out, go all the way and install new screws, and charge the magnets individually while you're at it. Charging magnets on the flywheel I got them to hold the traditional test weight of 2 pounds. Charging them individually off the flywheel I got all of them to hold 4 to 4½ pounds. Others using stronger chargers have reported achieving greater test weights but I think four pounds is more than good enough.
http://dauntlessgeezer.com/DG88.html

[speedytinc]

Give each magnet a ring test. Looking for that cracked magnet that will come off down the road. Belt sand the outer bent end for a visual of a crack. Not as common as a cracked drum, but common enough to check em all.

[Ron Patterson]

I am no fan of sanding the magnets. They may not be fully cracked through the metal.

Hold each magnet at the vee end between your thumb and forefinger.
Rap the end of the magnet on the anvil of your vise and don't be bashful about it.
If it is not cracked it will ring like a tuning fork.
If it is cracked the magnet will break into two pieces and don't be surprised if it does not break at the vee which would be the logical spot. I have seen them break in the middle of one leg.
.

[Dave Young]

Thanks guys. Steve, your article and photos of the process is a fantastic bit of information.

[Art M]

I recharged my magnets when they were off the flywheel. I wrapped #12 house wiring around the magnet and flashed it with a 12 volt battery. 22 windings on each leg. Each magnet would lift a 4 pound hammer. I tried 18 volts but the wire ends burned and the magnets weren't any stronger..

This procedure is slower than other ways. The faster way is to use the magneto coil.

Art Mirtes

[OilyBill]

Also, note that the retaining screws are NOT BRASS. THEY ARE BRONZE, which is twice as strong as brass. If you need replacements, go to a marine supply or boat store. They will have BRONZE screws. for you to use in magnet mounting.

[jab35]

If sourcing bronze machine screws from boatbuilders, be absolutely certain of the correct ones for your engine. Originally Ford used 14-24 screws, modern replacement ring gears are 1/4-24. jb

[Scott_Conger]

William

what is your source of information regarding the screws being bronze?

I have never torn down an engine that had bronze screws. And according to factory drawings, that is because they never built one with them.

Here is Ford's drawing, which specs 35,000 Elastic limit and 50,000lbs Tensile strength (the red annotation is not from me, it was from someone else pointing out the correct thread call out).

Brass has elastic limit of 70 ksi and tensile strength of 52,200 psi
Bronze has elastic limit of 65 ksi and tensile strength of 34,800 psi

in a previous post you suggested that folks should use bronze as it was twice as strong as brass, and now you are stating that Ford actually used bronze. Neither is correct


Dave

once you ascertain which threads are in your ring gear, you can purchase the correct screws from one of the suppliers and have full confidence that what you purchase will serve you very well.

[CraneJon]

A few thoughts that I have experienced.
1. Remove the magnets from the flywheel
2. Give them the "ring test" by slapping lightly on your bench vice. You will be surprised when one of them breaks in two! Better there than in the engine.
3. I gave the magnets to a hit or miss guy who recharged them. Hung them from a string above the charger to get them correctly oriented before charging.
3. Use Brass screws to fasten the new magnets. Be absolutely certain to peen over the ends that come through the flywheel so they do not loosen.

just a few ideas on the job.

[Mark Nunn]

Brass has elastic limit of 70 ksi and tensile strength of 52,200 psi
Bronze has elastic limit of 65 ksi and tensile strength of 34,800 psi

Scott's elastic and tensile numbers are reversed but his point is valid. It should read as follows.

"Brass has elastic limit of 52,200 psi and tensile strength of 70 ksi
Bronze has elastic limit of 34,800 psi and tensile strength of 65 ksi"

[Ron Patterson]

Notice that the print for Ford Factory Number T-625 indicates the magnet clamp screw was manufactured from "S Brass"

[Jim_Basile]

This is how I recharged mine. 100ft 10ga wire wrapped around a 1" chunk of steel rod, two charged up 12v car batteries, and a starter relay.
https://youtu.be/iaLXR0Wueuk

[J1MGOLDEN]

An earlier version of the MTFCA book on The Model T Ford Electrical Systems had a diagram and details on how to build a Magnet Charger and that one worked.

I had one, but lost, sold or gave it away.

I found the same details in an old Model T Club magazine, but I do not remember the club magazine or date.

There are two types, one charges the magnets removed from the flywheel and the other one charges the magnets on the flywheel.

I would like to build another one that works!

Any help would be greatly appreciated!

I do have a tool to measure the Gauss or magnets strength.

They are out of production, but may be produced again, if there is sufficient demand.