Welcome to the forum Abisel!

There are many more knowledgable people on the forum that can help you, but I am working on similar issues.

I tried super glue on a motor gear. Held for a about 3 minutes of running and then slipped again.
I have heard mention of Locktite on other posts, but have no knowledge of it myself.
My motor gear was replacable and in this case I bought the 5 pole motor kit for it.
So, yes, many older motors can be converted.

Do you have local Marklin dealer to help you with spare parts? Concerning smokestack, that is likewise an interesting question for me.
The smokestack on mine is intact, but worn and chipped. Would love to know if its replaceable.

Re: "Use the set-point and strike the inside of the wheel to close up the axle hole? Please advise."
Personally, I would not do this. A dealer might have the correct equipment to reset this.

Hopefully others will offer some more advice and hope you enjoy the forum, advice, photos, and all.

We like photos here, and sometimes kid each other in good fun.

Peace,
Mark

Hello

Good idea, old Märklin locos are the best.

And you have a couple of treasures there: a 3025 is really a sought after collector item.

Having run a Märklin Service Station for a few years, I have seen dozens of these cases of "slipping drivers"

The only durable way I know to fix this is to *lightly* knurl the axle, then re-press the drivers on the axle.
Knurling requires a lathe (+ knurling tool) and re-assembling requires a wheel press (+ appropriate pick-up inserts) , along with a quartering device to ensure the drivers cranks are exactly 90 deg. apart.

If you have these tools in your arsenal...I can give you the procedure...(although I'd suspect that if you do own these tools, and know how to use them you probably won't need any further instruction )

As I no longer live in the US, it would be hard for me to help you here, however I do still have a colleague in the US that I am sure would be ready to help you.

As for the "fiber" smoke stack , I have no idea of what you are referring to: this loco had a full metal body, and it looks as if the stack was filed off.

Contact me with a PM if you are interested.

Cheers

Thanks to everyone for their replies.

*lightly* knurling the axle is probably the best solution. I do have accsss to the tools and will look into that solution.

The smoke generator on this loco slides into the stack and makes electrical connection with two contacts behind the light bulb. The outside body of the smoke generator is insulated from the body of the loco by the fiber composite smoke stack. Yes the stack was filed flush to the body some 10 years ago and forgotten about. Now it needs attention.

After some serious cleaning, closer examination of the gear train shows some wear. I could use a complete set of gears. This loco was run hard back in the day and all the teeth of each gear are worn and do not mesh very well. Backlash is excessive.

Then there are the brass/bronze bushings for the axles of the wheels. These axles have a lot of lateral play. Has anybody found a solution to replace these bushings? Maybe the miniature brass tubing from the model shops would work. Or the miniature bushings found in precision instruments. ID needs to be 2.5mm, OD no less than 3.5mm and a length of 11.5mm.

Standby as I pursue options.

Thanks again for replies. Jacques, I will look into repair parts per your PM.

A couple more tear-down pictures:

Hi Abisel and welcome to the forum,

these locos have taken a lot and I've bought one and must have been through the mill.
unless the gears make the loco stop at any given point I wouldn't worry too much about the gears been worn but there is a limit and to what extend,
another fact I noticed again on your first photo, the middle axle wheel isn't worn at all and this is another example, whereas Märklin had raised the middle axle slightly and this is also apparent on Co-Co locos. good luck with your repair.

regards.,

John

Edited by user 11 December 2012 05:29:58(UTC)  | Reason: Not specified

Simple!
99% of the gears used in Märklin locos are "mod 0.4" (the metric equivalent to the diametral pitch standard)

All it takes is to invest in a set of 8 gear cutter wheels for the given module ( a US $ 500 ~ investment ) , used on a milling machine in conjunction with a divider/rotating table.
More than long explanation, here's a pic of the cutting of a angled pinion to mesh with the worm gear on a 3125 Red Arrow.
The second picture shows teh gear mounted on the axle, and you can see le light knurling I imprinted on it to ensure a lasting "grip".
(Same idea for re-assembling the wheels/drivers.. )
Straight gears are manufactured the same way, the axles are just then made perpendicular on the machine.
Not a fast process..but who's in a hurry?
The tricky part is to assemble "compound" gears with two different sizes permanently pressed together, like those found on many locos.
Special care has to be taken to ensure minimal excentricity...so careful centering and and flawless indexing on the lathe and milling machine are critical. (excentricity <0.02 mm is required for small gears)

Hi Guus!

Not hard to do, it is rather a matter of having the "tricks" to get the right results!

With bushings, it is really a matter of having the proper tools and make the right decision wether to "replace" or "refill".
In the case of a 3027 and other similar Märklin loks of these vintages , where *all* axles are driven through gears, the precision of the axles' spacing is a little less critical since there is a little bit of longitudinal "play" in the coupling rods.

But what is paramount is perfect parallelism (and after re-assembly, perfect quartering of the drivers...) !

So rework or replace is the good choice in this case IMHO.

In a 3027 case, I'd press the worn bushing out, and first try to knurl the outside surface of the older part.
This procedure will tend to press the material together, reducing slightly the inner diameter and when re-inserted (with a parallel press!!) you will probably have compendated for the wear-out "play".

That failing, it is rather simple to use the lathe to make a new bushing.

Turn the outside diameter to be approx 0.05 mm (1/20 th mm) larger than the hole in the chassis, but create a 0.5 mm chamfer on the edge to facilitate insertion in the chassis.

While still on the lathe, use a center drill to start the center hole, then drill it to 2.4 mm (or better to 2.45 mm if you have such drill)
Use lots of small strokes, clean off the chips on the drill after each stroke and use a lot of cutting oil to avoid overheating/breaking which always leads to an unusable part...
"
Since the hole you drill is always a little larger than the nominal diameter of the drill itself (due to a inherent but light "off-center" of the tip...), you'll have a good chance that the final hole diam is going to be "right on"....(i.e 2.53 to 2.55 mm)
Insert in the chassis (need a parallel press here..) and verify that the axle enters and turns without excessive play...

If not, use a hand reamer to progressively increase the inside dimension.
Work progressively and equally on both ends, so you will minimize induced alignment errors.

Most important tool: patience!

Usually, working fast means failure.

Voilà..you're done!

Hi,
Combined machines like the one you show are in fact less flexible than separate ones
I discovered Sherline 12 years ago....( http://www.sherline.com/ ) and I have never looked back!
They have everything: the machines, the cutting tools, instructions books with all kinds of tips and tricks, accessories with detailed instructions and suggestions, and last but not least an impeccable customer service attitude.

Their website is an infinite resource to help solve problems and answer questions: take the time to browse and you'll go crazy!!

Some clever accessories are very specific to Sherline, which make it an extremely versatile line of products.

When I left California for France I was a bit worried that it would make the relationship a little more difficult, but I was wrong!

They were especially helpful in the exercise of converting the equipment from the US system 60Hz/ 130 V to European 50Hz/ 240 V.

To me, they are the best I know for our kind of work.

Cheers

Thank you very much Jacques for your extensive information on how to replace and remanufacture a worn bushing.

Although I'm not unfamiliar with machining, I think at this stage I'll try and get a replacement bushing at one of the restoration firms.

The website you recommended is a tremendously good source of information. I bookmarked it right away.

Glad to see this thread getting so much attention.

I have sourced a precision bearings/bushing manuafacture that can make new bronze alloy bushings in 2.5mm ID, 3.5mm OD and 12mm OAL at a cost of $7.50 each. I specified these dimensions because of the measured dimensions of the axle (2.48mm), the OD of the existing bearing (3.48mm) and the OAL of the existing bearing (11.05mm). So how many should I order and pass on to fellow MRR's? I am also asking for a quote for oil impregnated bronze alloy bushing of the same size. Are there any other sizes to consider?

Edited by user 12 December 2012 23:52:28(UTC)  | Reason: Not specified

Well, your avatar doesn't tell us where you live/ to ship to.
But check the "Dealers" tab on the Sherline Home page, you'll be surprized how well they are represented, especially if you are in Australia (did I guess it right?)
Cheers

Yes you guessed right. I will check it out more thorougly later but having someone importing them here doesn't always mean a good deal. I have also found some strange things about the links on dealers. I'll let you know what I do once I am ready to get into this in few months hopefully.

On the manufacturing point. Are you aware of the technology called 3D printing? Some of these printers are no good for quality but there are some that are and there are very interesting options for producing quality plastic parts. You can make things like a tender case, even mechanical parts. What I am yet to see is the durability of the material if put under stress like gears.

It's looking like a great rebuild! So, the bushings aren't holding tight on their own?

Knurling is great...but it should be straight if you want to facilitate insertion of teh wheel or bushing.
No?
Cheers

Extremely nice and informative topic!

Thank you very much to all, specially to Jacques.

Regarding the chimney inserts:

https://www.marklin-user...imney-manufacturing.aspx

Good job!
Looks very professional.
Having one of them going "sideways" is not rare (I have had it many times... ) but I guess it is just part of the job.
But knowing how to recover creates confidence that you can succeed in 100% of the cases.
You are clearly on the right track (pun intended!)

Next challenge is quartering, so I suggest you do not assemble the motor etc. before you are sure the drivers, side rods and driving rods are all turning smoothly and not bending.

Another "trick from the bag": when you test it, drive the mechanism with your finger using the wheel on the geared side of the last axle (the one closest to the motor), both in forward and reverse motion.

This way you minimize the risk of slipping the wheel but also maximizes the "slack" in both direction, which will convince you that teh whole thing is now going to perform "silky smooth".

You do have a little leeway since all the driving axles are geared and the side rods have wider holer than the crankpins.

Looking forward to the next "épisode".

Cheers

An update:

Like I said before, if I didn't like the paint finish I would strip it off. Well, that is exactly what happened.

The RustOleum rattle-can paint just isn't durable. So what would be a durable scratch resistant finish for Marklin locomotives?

Then I got to thinking about DuraCoat firearm finishes and will be looking into that product. They have a ton of colors (that can be mixed) and the paint is a 2-part product. Pigment and hardner which is designed for air brush application. Even though DuraCoat is designed for firearm re-finishing, it can be used on anything.

This link has pictures of the so called assault weapon so be advised.
http://www.houtsenterprises.net/dur_starter.html

I have asked for color samples and will see what they have in matte or semi-gloss black, and the same for the fire red used on wheels, chassis, etc.

Excellent work, Keep posted!

I can only say - very educational topic, thanks to everyone participating and giving valuable advice!

Absolutely!
A good etch/primer is prim-ordial!
Good job.
Looking forward to th "mechanical" results!

@"Iamnot..."
You are right about detail and excess paint.
However, detail is not really a preoccupation on the underbody/chassis.

That said, not doubt an airbrush lays paint down much more thinly.
(I am still thinking of investing in an airbrush set when time and time gets there.)

@Rick, would love to hear more about how you apply primer on your parts.
Another post/thread perhaps.

@abisel
I am still curious how you plan to fix/recreate the chimney
- Mark

We certainly learn a lot in this topic!!!

I dont know how hot will the plastic get. I will suspect that the plastic might melt if it rises to high. It is a matter of a careful experiment. A metal tubing sleeve within the plastic insert might work. As you can see from the picture, the bottom of the plastic piece is closed, it needs to be cut. I did not cut it since I am not using a smoke generator. You may try to experiment first outside the engine by rigging some device to hold the plastic piece, the smoke generator and the wiring together to activate the smoke. Good luck!

I missed this thread first time round but I am interested in the discussion about replacing the wheel-axle bushings.

I had some worn ones in a 3001 chassis many years ago and ordered replacements via the agent - supplied as Marklin part number 20025.

I was surprised to find they are supplied solid. I asked the person who was then acting as service agent how he drilled them out but that was considered a trade-secret. He'd do it for me but not tell me how to do it. Okaaaaay, so much for give a man a fish.... (I didn't have the tools to do it anyway but still wanted to know the theory behind it)

Another engineering friend did it for me quick as a flash but I always wondered why Marklin supply them solid rather than drilled. Is it preferred to fit and then drill them? How do they do it in the factory? - (maybe I should email and ask) but I'm interested of course in the comments here - so why are they supplied solid ex-factory?

Good topic

Steve

Top image is of new bushing end-on, lower image after drilling (click to see them clearer (smaller)