I'm in the process of rebuilding my flywheel (clean and replace triple gear pins) and was wondering what is the preferred method of marking the magnets.
I do have some number stamps, just not sure if it is good to pound on the magnets. Or should I use a scribe and mark.
Thanks in advance
Use a "paint pen" available at Hobby Lobby or auto parts store.
I use the 'paint pen' made for metal marking, withstands a bit of everything.
And a bit anal in removing the replacing the magnets in the same relation as original, including marking where the flywheel dowels are located, so the matching pairs (N/N and S/S) of magnets go back on the flywheel as originally removed.
A wood container to handle them and keep them in place is easy to make.
As long as they repel each other as you replace them it makes no difference. KGB
I think it's a good idea to mark their polarity before removing them from the flywheel, and be sure to charge them in the same direction as they were. In other words, don't reverse their previous polarity when charging them. I don't think they'll hold a charge as well if you do.
I believe there may be enough difference in the weight between them that you should keep them in the same order and relationship to the flywheel to maintain the flywheel balance.
I first wash the fly wheel with solvent, gas or whatever then mark them for removal. Be sure to keep the poles in the right order. When you mark them, first use S1 S2 N3 N4 and so on. Doing it this way keeps things exactly right in case you drop them from or get them mixed up some way.
Everything will be exactly as it was.
"Everything will be exactly as it was"
Only YOU ARE THERE!
(Old TV show that re-enacted historic events, like sinking of the Titanic, etc.)
I couldn't resist!
BTW, good thread, think I'll make one of those magnet holder boxes for myself! Don't forget to check for cracked magnets! Oh, and striking a charged magnet is a no-no!! Striking during charging is supposed to help lock in the atomic alignment though (well, that's what I've heard).
Dan -- In your pic above, I see your charging setup has muchos turns of wire around each pole. I recently borrowed a similar setup from an old-timer here, and he made it with one layer of wire around some pvc pipe -- 19 turns per leg. It charged a set of magnets, but not as much as I'd like. Does having more turns of wire result in a heftier charge?
Mike -- Yes, add many turns to the simple wire wrap method of recharge, that improves the result.
Here is an old write up from the period,
Wow! That says at least 75 turns on each leg! I guess I'd better go to the parts store and buy some more wire.
Go the the home supply store rather then the (auto) parts store to get wire. You want solid conductor wire so it will hold its shape.
I have rebuilt many Model T flywheels and here is what I know to be the truth and what I have learned.
It is not absolutely necessary to keep track of the polarity of the magnets when you remove and clean them. The magnets are forgings and marking them with stamps is a waste of time. After they are cleaned they can easily be placed on a bench and the original NN SS NN orientation re-established. Each magnet must be checked for cracks, there is a 50% chance at least one or more will be cracked and need replaced. .
Recharging the magnets requires at least 5000 Ampere turns. Some of the information given here is factually incorrect (75 turns using 10amps) and some practically impossible to recreate (using 110 volt ac for recharging magnets).
An original Model T magnet recharger is a very large device.
but you can replicate the necessary 5000 AT windings pretty easily with the right combination of wire length, direct current applied and measuring the amount of amperes flowing. You should reuse the aluminum magnet spools (they ares soft and can simply crumble when setting the magnet height), but you can reuse the brass spools. Always reuse the original Ford magnets clamps, the reproductions are soft and will easily bend. Always replace the magnet clamp screws because the heads are usually crystallized and can easily break off when reused.
Always be sure to get magnet clamp screws with the correct threads to match your flywheel or ring gear.
There are several methods for properly setting magnet heights. Regardless of which procedure you use they all should be within a few thousandths the same heights when measured from the transmission stub shaft mounting flange and you will be OK. When done distort the edges of the tips of the screws to prevent them from coming lose.
Finally you should always have the completely rebuilt flywheel rebalanced
The learning curve is a bit steep the first time you recharge magnets, but after you do it correctly once it is easy from them on. If you need any help give me a call.
Ron the Coilman
Oops; You should NOT reuse the aluminum magnet spools.
I agree with Ron in most respects. There is no need to keep the magnets in anything like the original order, as the assembly when completed should always be re-balanced. I believe the flywheels were balanced before the magnets were fitted in the factory. Those large drillings are under the magnets when installed. Then they added all that hardware!!!
Once one magnet has to be replaced due to cracking and or breaking, the original "balance" is disturbed anyway.
Hope this helps.
Allan from down under.
My first plan was to get a new set of spools, so the magnets would all be the same height and then i would not have to mess with the K R Wilson tool.
Nothing could be farther from the truth.
The magnet heights varied by as much as .022 from thin to thick.
Recharging magnets does not have to be complicated. As to setting heights, I have found its just as easy without the tool as with one. A good mike, dial caliper, and set of feeler gages are all that's required. A transmission sling, like that found in the MTFCA transmission manual will come in quite handy.
I see no reason to mark the magnets. I suppose one could mark magnets, spools and spool positions, but its never been worth the bother for me.
Reading James' posting noting the variation in magnet thickness; would it be worthwhile to place them in a milling machine and make them all the exact same height?
I think machining them to the same thickness is a waste of time. I think that's why you have to set the magnet heights in the first place since the magnets are the least precision made part of the assembly.
I'm no machinist but if someone tries it, they'll probably need to keep air blasting on the cutter head to keep the magnet chips from sticking to everything in the vicinity of the cut. Then consider where they go from there and getting them out of everything else they land on.
Hmm, good point Warren, I hadn't thought about the chips being magnetic!
Ted can you explain your setup in more detail (wire size, turns etc)
Here is an opportunity for some creative person. Just as Gary Tillstrom did for the HCCT, why don't one of you come up with a complete set of instructions for building and operating a proper Model T individual magnet recharger? That should include a complete parts list including the electrical components (with all the proper electrical calculations satisfied, wire size, number of turns, pole size and pole core materiel and method for crack checking the magnets) that can utilize one or two 12 Volt batteries for power and will produce the necessary 5000 Ampere/Turns magnetic power to provide a full saturation charge to a Model T magneto magnet.
Ron the Coilman
Try this one on for size: http://www.oldengine.org/members/rotigel/magnet/