Back to the Penn Line Atlantic

Well, I got the whole thing assembled, and decorated, and it looked beautiful... but wouldn't run. It *had* been.... So I've been fighting shorts, and bad power packs, but now I've got a major problem: one of the drivers on the axle with the gear is loose. I've tried Crazy Gluing it without taking it apart, and that seems to have just given up the ghost.

Tonight, I took it mostly apart, and tried to force-fit it over the axle... and it's still loose. I'm thinking that the hole in the wheel is worn at this point.

So far, I've had two ideas: first, to Crazy Glue it again, this time from both sides, or second, to tin the axle with some solder and then force-fit it on.

Or I could spend still more money, and buy a new wheelset from Bowser.

Suggestions? Recommendations?

mark "and it looked gorgeous...."

Reply to
mark
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Best bet is a new driver set.

Trying to re-install the present driver on the same axle is fr5ought with problems. Quartering Present 'loose' condition possibly points to 'Lead Pest', 'Zamac Dry Rot', or any of he many other possible names. Of you proposed methods, the 'tinning the axle end' to increase it's size is the best possible method, but you need to make sure that you don't end up with the wheel being 'off center', as well as maintaining the 'quartering'. Missing by just a whiff of a Thousandth will show up as a quite noticible 'lurch' as the loco moves down the track.

Chuck D.

Reply to
Charles Davis
[ Snip ] loose wheel

You might try one of the Loctite products instead of crazy glue. Some of the products require torch and sledge hammer to separate parts once attached. Make sure you get the quartering exact or you'll have to go on to your next option.

Reply to
<wkaiser

I gather this was an ancient 2nd hand loco, and not a kit bought recently from Bowser. I suggest you buy all new wheel sets. That way you'll be sure that all wheel sets are solid, and the quartering will be the same for all. Besides, you've invested a lot of time and effort in this loco, so what's a few dollars more to get it to run right?

Charles Davis alluded to 'Lead Pest', 'Zamac Dry Rot', etc. If you want to know the gory details, try Wikipedia. It's bad.

Good luck.

Reply to
Wolf K.

I've already spent more than I would have if I'd bought it new from dealers....

Sorry, neither google nor wikipedia knows anything about either phrase. Care to explain?

mark

Reply to
mark

Try *zinc pest*. HTH

Jerry

Reply to
trainjer

It's more commonly called "zinkpest". It comes from tiny percentages of lead getting into the casting material. The effect over time is that the lead oxidises and expands, often causing a white bloom which expands the casting fractionally and causing it to crumble. It was generally normal in prewar models, which is why few remain intact, and was gradually recognised and eliminated in the 1950s. Maerklin has recently produced/had produced a batch of models which suffer from the problem, so it's not eliminated yet.

Regards, Greg.P.

Reply to
Greg Procter

Something similar can happen with pewter.

Reply to
video guy - www.locoworks.com

That citation surprised me, but I hadn't looked there (still haven't)

The terms are refering to what happens to Zamac over time. sometimes a few years, sometimes 30 or more years.)

The Alloy Zamac does not normally contain other than trace amounts of Pb (lead, to the rest of us)

The 'casting process' involves heating the alloy to the liquid state, so that it can be forced into the molds, where it cools, and retains the shape of the mold. This period of 'HOT state' starts the Pb, and the other components also, oxidizing. The other parts of the alloy are pretty much 'self limiting' in how much oxidization occurs, Pb isn't (self limiting) the lead oxide is porous, and provides a path for atmospheric oxygen (in the air your breathing) to continue the process with the next molecule of Pb. Depending on the Alloy 'MIX' this may rang from fairly fast, to very slow. Now this 'oxidation' process wouldn't be much of a problem, except that the Pb oxide molecule, is physically larger than the Pb molecule {like water/ ice), this pushes the fabric of the casting apart and results in microscopic cracks, that grow more noticible over time. These cracks, also destroy the physical strength of the metal. Sometimes to the point of being left with a 'pile of metal dust'.

With a CLEAN Zamac mix, the castings are pretty stable. Re-melting defective castings to re-use, and using 'scrap' zamac instead of 'new' [metal shortages after WW II, during Korean Conflict, and sometimes COST] have a bearing on the 'life' of the casting.

I know this seems Looong, but it IS the short version.

Chuck D.

Reply to
Charles Davis

Try "zinc pest".

Reply to
Wolf K.

That's *weird* - "zinc pest" gets nothing, but *zinc pest* gets all the hits I need.

Anyway, no, this is probably very late fifties/early sixties, and made in the US (Penn Line, and *everything* that came with it was in bags with Bowser on the card.

The motor, on the other hand, seems to be *incredibly* touchy. No contact, contact, *loosen* the screw at the back that holds it together, it moves more, and on, and on....

mark

Reply to
mark

Ah, yes, Pittman motor design and the march of time.

The motor shaft bearings are 'more or less spherical sintered bronze, with a shaft sized hole through them. They are held in place with a brass collar forcing them against a tapered hole in the end plates. That 'force fit'[and drying of grease & oil] doesn't do anything to align the hole in the bearing accurately with the armature shaft. any 'mis-alignment' causes 'drag' for the rotation of the armature. The FIX, is to free up that semi-solid mount of the bearings, so that they can align themselves with the armature shaft.

Chuck D.

Reply to
Charles Davis

Chuck is right IMO. Oil/grease oxidises and turns into a varnish-like substance. Use a light oil or contact cleaner/lube to loosen it. Wiggle the shaft and spin it by hand. Clip leads to the motor and run it a minute or so in each direction, wiggle shaft and spin it by hand, reapply the light oil. Then dunk the whole thing into a bowl of methyl alcohol, and turn on the juice. There will no danger of fire because there's no air in the meths. Run it a a minute or so in each direction. Turn off the power before lifting the motor out of the bowl. Let the motor dry, and apply light oil to the bearings. This method will also clean the commutator, leaving it very dry, so a minute drop of contact lube should be applied.

You may also find that shim between the frame and the motor will help align the mesh between worm and gear. The worm must not bottom out on the gear.

HTH

Reply to
Wolf K.

snip

More on 'Motor Tuning'

The 'brushes' [applying power to the commutator] are very sensitive to having the correct pressure. To 'find the sweet spot' ; With the motor 'out in mid air', apply power to make it run about 'mid speed' [i.e. NOT wide open]. using something soft & flexible, Gently apply some pressure to one of the motor brushes. IF the motor speeds up, that brush needs to have a slight bit more tension with the spring. IF it slows down, you should try 'loosening' the tension for that brush. Repeat for the other brush.

The motor will also benefit from efforts to reduce/ eliminate 'Longitudinal' play. [The shaft pulling into or sliding out of the motor.] To add washers on the motor shaft within the motor, loosen the assembly bolt, this will allow the front bearing assembly to be rotated, releasing it from it's attachment to the pole pieces, slide the bearing plate forward some. [You do NOT need to remove the worm. We are NOT trying to reduce the motor to a 'box of pieces'.] This will allow you to slide the armature SLIGHTLY forward, enough that you can 'add/ subtract' washers as needed to resolve any 'slop' problems.

DO NOT REMOVE THE ARMATURE from between the pole pieces. Doing so will break the magnetic path (magnet/ pole piece/ armature/ pole piece/ and back to the other side of the magnet.)

After adding/ removing armature washers, Re-mount the front bearing assembly, Re-tighten the motor assembly bolt, and IF available Re-Magnetize. If you have been careful, and minimized any 'breaks' in the magnetic path, things will be better. Any 'breaks' in the magnetic path during the 'work' WILL have an effect on he motors operation. [The bigger the break, the worse the motor will be.]

The loss of 'magnetic flux', while NOT instantanenous, is a bit faster that I can work. (Dis/ Re -assemble.)

Re magnetizing cures this possible gremlin.

Chuck D.

Reply to
Charles Davis

On 4/11/2008 10:19 AM Charles Davis spake thus:

I don't know where you get this from; you seem to be repeating an old myth about permanent-magnet motors. Disassembling such a motor doesn't change the magnet at all. Think about it: why do they call them "permanent magnets" in the first place?

Other than that, your advice was good.

Reply to
David Nebenzahl

Older magnets loose a degree of their magnetisim when removed from the motor frame. It's fact. Only modern (last decade or so) magnets can cope with such treatment without losing strength. Why do you think all seperate magnets have come with metal "keepers"?

Regards, Greg.P.

Reply to
Greg Procter

Since Model Railroaders are quite often working with 'Old Technology', it (the myth) is pertinent.

Right! But with the older Alnico magnets (which aren't up to present day standards) the "Motor" will be affected. The reason being: The motor magnetic field was established AFTER ASSEMBLY. The Alnico 'slug', the soft iron pole pieces, and the armature providing a complete/ stable path for the flux density remaining after the 'magnetizing operation'. This is the 'normal' operating conditions for that particular motor.

The Alnico 'slug' is able to retain the 'flux field' at that level because of the pole pieces, and armature that complete a magnetic circuit. This is a 'higher level of 'magnetic flux' than the Alnico slug will support 'Without' the pole pieces & armature in place. Remove there 'accessories' for a bit, and then replace them, and you are stuck with ONLY the amount of flux that the Alnico slug can support by itself, the additional flux is no longer available. [Unless you Re-magnetize the motor assembly.]

This is 'old tech.', but that's what those old 'open frame permanent magnet motors' were using.

'Permanent Magnet' is a 'relative' term. The 'newer' "Rare Earth" magnets have been mentioned. When those were first appearing in the market, they were often referred to as "Super Magnets".

When working with PMs, be aware that they can 'lose' their magnetism, the field can be partially destroyed, it can even be reversed. Just remember, that 'Permanent' is only 'permanent' under some conditions.

Thanks, I try to be accurate, but "English" is not a very precise language for explaining things sometimes.

Chuck D.

Reply to
Charles Davis

Ah, being the guy who started all this.... Yeah, I saw the forward-backward play in the motor as soon as I got it to run, then put it on the frame. I've taken it apart, and put two washers in. No, no magnet looses its magnetism in this case - that's silly. Don't believe me? Ever had a Wham-o Wheelo, the wire frame with a wheel with a magnet as an axle? They're been around since the sixties, and if you leave the wheel off, it doesn't "loose" its magnetism.

For that matter, ever heard of this thing that they invented for ships called a "compass"? That's basically a bar magnet.

Anyway, I'm working to eliminate shorts - *geez* the tolerances on this thing! I've already had to line the body around the motor with electrical tape, and cut some plastic that comes with a new shirt, under the collar, to put between the insulated wheels and the frame, and the motor, and the trailing truck insulated wheel and the frame, and on the tender, *more* electrical tape between the insulated wheels and the screws.....

Right now, the wheels move if I push it, though every so often, it starts to go on its own. Oh, and the headlight won't go in, with the wires attached to the springs that hold the brushes tensioned, even when I drank the power all the way up (and yes, touching the wires to the track, it lights up, so there's no short there), and I've found that the damn thing wants more current than a 9v battery provides (different bulb, in my hands).

Ghu, if I'd known all this, I wouldn't have bought the damn thing off eBay, but looked for discount retailers and bought a new kit.

mark, with hopes that pushing it back and forth will break it in more

Reply to
mark

What you need to aim for, is a 'minute' bit of play. Almost to the point of there NOT being any play. But, there needs to be enough play, that there isn't any 'binding'. Figuring 'typing paper' as .002" thick, and 'tissue paper' being somewhat thinner, you want about 1/2 of the 'tissue paper' thickness.

No, no magnet looses its

Right!!! Permanent means permanent, or they wouldn't say it! I hear there is this 'suspension bridge' available for sale in Brooklyn. You might be able to make a good deal, set up Tolls, and make a killing.

[Yeah, Right!!!]

Don't believe me? Ever had a Wham-o

No, because it was never designed as a 'closed circuit magnetic field'. therefor you DON't see any degradation over time.

You are finding problems that shouldn't ever show up. They were designed to be workable WITHOUT all the extra insulation you are mentioning. [Unless the thing has spent sometime wallowing in dirt (kids sandbox maybe)]

Quite possible!!! Those motors, when running well, want close to 1/2 amp of current. your usual 9v battery, while capable for a SHORT time, doesn't like that sort of load, and the 9v will drop off (you may be doing good to have 4.5v).

But look at all you have learned!!!! The next one will be a 'piece of cake'. [and it could easily be something that isn't available for any price in the 'retail arena'.

Chuck D.

Reply to
Charles Davis

Next time you get one of those motors in your hands, remove it from the loco and apply 12 volts. Then measure the current. Next remove the magnet, leave it for 24 hours, reassemble, apply 12 volts and measure the current draw. If there's no magnetic loss the current draw should be exactly the same

- it won't be or I'll owe you a beer.

Regards, Greg.P.

Reply to
Greg Procter

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