Making a magneto crank smoothly again

[Craterranch]

Hello. I removed the magneto from a junked Federal set and I'm going to make a little demo setup with it mounted to a board and hooked up to the ringer, maybe a light or something. Anyway, the crank doesn't turn smoothly. It turns maybe almost a full turn before it binds up, and you have to give it a little extra umph to move it another turn. Not sure if the gears aren't meshing right, or maybe it just needs to be taken apart and cleaned up. The gears look clean enough. I was going to take it apart and clean, lube everything but thought I'd solicit some advise here first. Also wondering if what kind of lube is best, and whether or not to keep it out of the inside (I imagine it should be kept out). I appreciate any advice. The picture isn't mine, but looks almost exactly like it.

[unbeldi]

Have you measured the output voltage of the generator?
Make sure the coil or the contacts aren't shorted somehow, because when this is the case, a magneto becomes very hard to turn very quickly.

[Craterranch]

Have you measured the output voltage of the generator?
Make sure the coil or the contacts aren't shorted somehow, because when this is the case, a magneto becomes very hard to turn very quickly.

I have not, but it still rings the bell so does that mean it's not shorted? What do you figure the voltage should read?

[andre_janew]

The bearings could be a bit rusty.  My dad would tell me to use WD-40 on it to get it to turn easier.  However, using WD-40 is often frowned upon by many on this forum!

[unbeldi]

The bearings could be a bit rusty.  My dad would tell me to use WD-40 on it to get it to turn easier.  However, using WD-40 is often frowned upon by many on this forum!

On heavy gears like this, WD-40 is just fine to dissolve and flush rust and dirt and provide some lubrication. I just wouldn't get it into the coil on the rotor.

It is dials where is usually isn't recommended, at least not for final lubrication, as it may leave residues.

[unbeldi]

Have you measured the output voltage of the generator?
Make sure the coil or the contacts aren't shorted somehow, because when this is the case, a magneto becomes very hard to turn very quickly.

I have not, but it still rings the bell so does that mean it's not shorted? What do you figure the voltage should read?

Well, if it does ring the bell, it's probably ok.
What kind of ringer are you using?  High or low impedance?
I would expect to get 70 V to 90 V fairly easily.

[Craterranch]

Well, if it does ring the bell, it's probably ok.
What kind of ringer are you using?  High or low impedance?
I would expect to get 70 V to 90 V fairly easily.

It's the ringer from the same phone. Not sure of the impedance. It feels like the bearings are the problem so I'll try working on them before I take the whole thing apart.

[Ktownphoneco]

The primary purpose of WD 40 is to displace moisture, and to some degree, free up seized parts, although penetrating oil is best for that purpose.     It has very few long lasting lubricating properties, and it's a dust magnet.      I've been repairing and restoring magnetos for quite a while, and the best oil for the purpose of lubrication is probably the most obvious, but least thought of, and that's oil designed specifically to lubricate small electric motors, such as 3 in 1 electric motor oil.    The 3 in 1 product has an S.A.E. viscosity rating of 20, which is perfect for a magneto.
After all, a magneto has all of the components and similar bearings as a basic electric motor.

Small cans ( around 3 ounces ) are available at a lot of stores.    Lowe's carry it, and I'm sure a few other stores do as well.

Jeff Lamb

[unbeldi]

The primary purpose of WD 40 is to displace moisture, and to some degree, free up seized parts, although penetrating oil is best for that purpose.     It has very few long lasting lubricating properties, and it's a dust magnet.

I think that is a very commonly cited myth.
Excess lubricants after cleaning should in any case be removed, many liquids on surfaces attract dust.

The manufacturers themselves dispel the myth about the product that it is primarily for water displacement, despite the name.

     I've been repairing and restoring magnetos for quite a while, and the best oil for the purpose of lubrication is probably the most obvious, but least thought of, and that's oil designed specifically to lubricate small electric motors, such as 3 in 1 electric motor oil.    The 3 in 1 product has an S.A.E. viscosity rating of 20, which is perfect for a magneto.
After all, a magneto has all of the components and similar bearings as a basic electric motor.

Small cans ( around 3 ounces ) are available at a lot of stores.    Lowe's carry it, and I'm sure a few other stores do as well.

Jeff Lamb

Many products exist today for all kinds of specialized tasks and applications.  None works best for everything.   WD-40 is certainly not a specialized product. It is a general purpose product that works well in many situations, perhaps just not best in any. I am not advocating it for any particular purpose, but you can hardly go wrong with it on course gears like a magneto if you protect the electrical windings, not only from WD-40, but from any potentially insulation-dissolving agent.  Personally, for many tasks I use a type of oil by Marvel, but not for washing debris and rust from parts.

[Craterranch]

I restore antique radios so I have Deoxit on hand (it's basically WD40). A little squirt into the bearings and they freed right up. I applied a little light machine oil to keep them lubed. Poor things probably hadn't cranked in decades and who knows how the phone was stored. Glad I checked here before I tried taking it apart. Just goes to show, always check the forum. Thanks everyone for your input.

[DavePEI]

I have to agree with Jeff... If you use WD-40, simply use it to flush off parts, then remove it. A toothbrush can be used to remove build-up on he gears. Lube with 3 in One oil as Jeff says. Use the blue version designed for lubing electric motors. A drop or two on each bearing,  and gears. Make sure the shaft moves freely. Now, it the coil of the magneto has a short, this won't help, but I have freed up dozens of sticky magnetos this way, and it works great. You should not have to dis-assemble the magneto, unless it is extremely gummed up. If you disassemble a three, four, or five bar magneto, mark the magnets so they all go back in order and in the same polarity. Ideally, while dis-assembled, you should put an iron bar or "keeper" on the end of each until replaced on the unit. That is why I suggest you try not to dis-assemble it if it can be avoided.

Dave

[Ktownphoneco]

To properly service a magneto, it's like any mechanical device, completely dis-assemble it, clean each part in some sort of cleaning agent that doesn't leave some sort of residue, including the machine screws that hold it together, so that the entire magneto is perfectly clean of dirt and old lubricant.      Re-assemble, and lubricate throughout the entire process, but don't go crazy with any lubricant.      Replace the oil wicks in the 2 holes that serve as lubrication ports at each end of the magneto.     I use small ( about an 1/8" inch in diameter ) felt plugs than insert into the oil galleries, then oil the felt until saturated.
That will give the magneto a whole new lease on life and keep it running for another 50 years.
I can tell you from experience, WD 40 is at the lower end of the lubrication scale.   Yes, anything that's a liquid will attract dirt or dust, but some are more prone to it than others.    What better lubricant to use an a magneto, than one manufactured specifically for electric motors.      I'm sure there are other lubricants in the market place that will do a good job as well, but past experience has indicated to me, that WD 40 isn't one of them.

Jeff
 

[dsk]

My experience of such inductors are limited, but sometimes you may get magnetic dirt inside, and that may jam the movement.
The gear looks nice, and the bearings probably are too.  Be careful with the magnet when you take it apart. As on ringers, the  magnet may be weaker.  You may try to blow it clean with air, or even mineral turpentine. The last will wash away older oil residues. For the gears and bearings synthetic oils will be perfect, but at least silicon oils are harmful for the contact set, even the damp from silicone oil.
Using thin mineral oil may last for 50 years before next cleaning, so it should not be to big of a worry.  (the same oil you would use on a bike, sewing machine gun or...)

dsk