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Possible Solution For Cracked Axle Gears...Thoughts???

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Posted by jjdamnit on Friday, May 28, 2021 12:08 PM

Hello All,

Going Off Topic here...

Einsteins' theory of relativity (E=MC2) was the biggest can of worms he ever opened.

So much so that it took until 1919, almost a decade later, to put all the worms back in this can.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by PM Railfan on Wednesday, May 26, 2021 7:30 PM

"As Albert Einstein was quoted as saying, 'When you open a can of worms the only way to get all the worms back in the can is to use a bigger can.' "

Thats because the vegematic wasnt invented yet. But what i cant figure is, as smart as he was, why would he open a can of warms in the first place?

 

Mischief

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Posted by jjdamnit on Wednesday, May 26, 2021 12:41 PM

Hello All,

Lastspikemike
A length of suitably sized silicone hose could perform the universal joint function. Not sure why these plastic Hooke's joints are ubiquitous but they are.

Thank you for your input.

On the HO scale Box Cab locomotives I have restored they indeed use a piece of silicone tubing as the linkage from the motor to the drive mechanism.

The I.D. of this tubing seems to be an uncommon size.

When I went to the service department of the original Caboose Hobbies in Denver, the spry old gentleman- -with a slight German accent- -produced a spool of the sought-after item.

Written on the side of the spool was, "DO NOT SELL!".

He mumbled to himself, "Vell, OK."

He asked me how much I needed. Then snipped off about a 6-inch segment from the spool.

When I asked him, "How much do I owe?" With a wink he replied, "It saz "DO NOT SELL!" zo I give it to you."

In these Box Cabs there is only about 1/16 of an inch distance between the motor and the drive mechanism.

They also run at an extremely slow speed so the torque applied to the tube linkage is minimal compared to the Bachmann GPs I'm dealing with.

Another aspect of replacing the O.E.M. linkage with a piece of tubing is the driveshaft (dogbone) has horned ball ends.

Between the horned ball and the main section of the shaft there is a 1/8-inch reduced section.

This section would need to be removed, thus adding to the length of tubing needed and increasing the twisting of the tube under load.

If I only remove the horns on the ball and push the tubing over it I'm afraid there wouldn't be enough contact area of the ball for a secure connection.

As Albert Einstein was quoted as saying, "When you open a can of worms the only way to get all the worms back in the can is to use a bigger can."

Because this problem has occurred on all eight of the Bachmann GPs in my fleet I would rather find a solution to replace the cracked worm gear coupling over finding a "bigger" can.

Again, thank you for your insight and suggestion.

I will update you with the progress of this "solution".

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by jjdamnit on Tuesday, May 25, 2021 7:31 PM

Hello All,

I contacted James at James train parts for a consultation on 3D printing for the parts I need.

Unfortunately, he is located in the U.K.

Noting wrong with overseas sources but the cost of tooling, printing, and shipping is currently cost-prohibitive.

I took another look at the solutions A-Line offers. I've ordered three components that might work:

  • #12033 - Worm Couplings
  • #40005 - Replacement axle gears
  • #12053 - Brass Sleeve 2mm diameter X 3/32 OD (4 ea) Used to convert 3/32 " ID flywheels to fit 2mm shafts.

I have several A-Line Universal Coupling Kits. The problem is the couplers are designed for a 3/32-inch shaft while the Bachmann shafts are 2-mm.

With the addition of the Brass Sleeves hopefully, I can finally find a solution to the failing Bachmann components.

So far, every Bachmann GP series worm gear coupler in my roster has failed and needed replacement. I've gotten proficient at quickly replacing this defective part, but only when replacements are available.

Currently, Bachmann only offers a complete powered truck. The Gear Tower is listed as "Out Of Stock".

I will keep all of you informed of my progress and will hopefully provide others with a viable and permanent solution to Bachmann's shortcomings.

Hope this helps.

 

 

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by jjdamnit on Thursday, January 7, 2021 10:51 AM

Hello All,

Excellent resource!

Thank you for the link.

I just reached out to him in regards to both parts.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by Overmod on Thursday, January 7, 2021 8:59 AM

ndbprr
Contact James at James train parts.

He has a 'shop' on shapeways.com, or a site with resources here.

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Posted by ndbprr on Thursday, January 7, 2021 7:34 AM

Contact James at James train parts. He has made several replacement gears for primarily n gauge but can whip it out in no time if he wants to produce it.

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Posted by mbinsewi on Wednesday, January 6, 2021 9:08 PM

jjdamnit
I am a member of the Bachmann Forums.

OK, so do the Shapeway, or what ever printing thing you have found. or want to do.

Simple.  Just do it.  

So far, nobody has jumped up, that does 3D printing, and said " Hey JJ I can do that!"

So search it out.  all of us that have responed to your post have given you the resources that have been "go to" places to find what you want.

jjdamnit
The reason I began this thread was to explore the possibility of having these unavailable replacement parts replicated by 3D printing.

So, go for it, and explore.  Smile, Wink & Grin

Mike.

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Posted by Overmod on Wednesday, January 6, 2021 8:22 PM

jjdamnit
The reason I began this thread was to explore the possibility of having these unavailable replacement parts replicated by 3D printing.

I'd be at least mulling over the idea of lost-wax (or maybe even lost-foam) casting.

Make it in metal, cross-drill and insert pins of correct dimensions for the pivots.  It will not shear, it will not break, it will not twist or distort.

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Posted by jjdamnit on Wednesday, January 6, 2021 3:59 PM

Hello All,

mbinsewi
Maybe try the Bachmann Forums.

I am a member of the Bachmann Forums.

The problem is...

Erie Lackawanna in Georgia
Seems to me the problems with these gears cracking over time is due to the selection of the original plastics used.

Bachmann has admitted that the plastic couplers between the metal worm gear shafts and the dog bone drive shafts are only available as a part of a major sub-assembly.

Which are currently "Unavailable".

The reason I began this thread was to explore the possibility of having these unavailable replacement parts replicated by 3D printing.

Thank you for all your suggestions and comments, keep them coming, and...

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by mbinsewi on Wednesday, January 6, 2021 2:14 PM

Maybe try the Bachmann Forums.

Mike.

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Posted by jjdamnit on Wednesday, January 6, 2021 12:40 PM

Hello All,

rrinker
...(T)he ones you need should still be available.

I've searched the Athearn/Horizon Hobby (Athearn's parts supplier) to no avail.

Not to be facetious but...where?

If you have a known source I'm all ears!

rrinker
The whole truck can be replaced (SIC) if you have the older ones - the plastic side frames are much nicer than the old metal ones anyway.

The tabs on the truck assemblies I am dealing with extend farther into the frame than the assemblies currently available.

I don't believe that the newer truck assemblies will fit the frame I have without major modification to the frame.

Athearn does offer HO Drive Axle Gear [ATH60024]. These might work for the cracked gears.

However, I still have the cracked Bachmann worm gear couplers to contend with.

Again, thank you for your suggestions. 

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by rrinker on Wednesday, January 6, 2021 8:46 AM

40023 is the complete wheelset, 2 stub axle wheels and the gear. You don't need all that if just the gear is cracked. And those are definitely the older outside bearing truck type. If your loco has the bronze bushings between the wheel and the truck sideframe, those aren't the right gears, the ones you need should still be available. The whole truck can be repalced if you have the older ones - the plastic sideframes are much nicer than the old metal ones anyway. Far as I know, th only old Athearn BB loco that never got changed over was the Trainmaster, probably because of the uinique offset 3 axle trucks. 

                               --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by jjdamnit on Tuesday, January 5, 2021 8:15 PM

Hello All,

Erie Lackawanna in Georgia
Seems to me the problems with these gears cracking over time is due to the selection of the original plastics used.

This seems to be the crux of the problem.

Lee 1234
Versatile Plastic material at Shapeways is plenty tough.

Thank you for the recommendation on printing material.

Lee 1234
Athearn 40023 is the part number of the old outside frame drive wheel assembly.

According to the original Athearn Assembly Instructions included in the box of the unit I am attempting to rebuild 41023/24 are the Truck Units for the Powered Locomotives. It also notes that the 41022 units are for the dummy locomotives.

The 40023 wheels sets are used on the F-7, GP-9, GP-30, GP-35, SDP-40, SD-45, and the SW-1500 Cow & Calf according to the original documentation.

Thank you for your suggestions.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by Lee 1234 on Tuesday, January 5, 2021 7:03 PM
Versatile Plastic material at Shapeways is plenty tough. All you need is a 3D CAD design of the part. Athearn 40023 is the part number of the old outside frame drive wheel assembly. You can get wheels sets from Northwest Short Line that fit the newer gear.

Lee

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Posted by Erie Lackawanna in Georgia on Tuesday, January 5, 2021 6:50 PM

Seems to me the problems with these gears cracking over time is due to the selection of the original plastics used.  POM or the more commonly used acetal are used in gears due to cost, dimensional stability and lubricity.

There are two types of acetal (as well as most polymers) homopolymer and copolymer.  Duponts Delrin is a homopolymer and they were first to market.  The homopolymers are inherently less expensive than copolymers, are stiffer and are subject to cracking and crack propagation over time.

Copolymers do cost $0.10 or so per pound more, have a lower modulus, are therefore more forgiving to cracking over time.

Manufacturers could do everyone a favor and specify any of the many unfilled copolymers available instead of the historically used homopolymer.

Just a thought....

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Posted by PM Railfan on Tuesday, January 5, 2021 5:14 PM

Hello Railfans!

Heres my experience with this very subject and 3d printing....

 

Can it be done? Yes. I have made for myself a replacement set of 3d printed axles for the Bachmann 2-8-0.

Did they work? Yes, to a degree. While the new parts served their function, the inherent bad design of this type is still a problem. Slippage will eventually reoccur even if it doesnt crack the new parts. Even replacement axles of commercial grade with eventually experience the original problem. Its plainly a bad design.

Are 3d axle replacements durable enough? Yes. They can take the load just as the originals do. But again, up to a point. the flaws of the design still overcome the advantages of replacement. Do know you can select the hardness of plastic you print.

Pro vs Con: Unless you are set up yourself to 3d print, it is more practical to search out and aquire commercial versions. If not found or not available, then someone like Shapeways ( i hear) or other company may be able to help. These are such small parts they might not be cheap for a company to make just one set. Its time intensive to design, populate, print, then test a part.

Only if you are able to print these up yourself would this be an economical process. Once you have the original you can reproduce as needed because but again, the flaw will always exist in this type of design. Youll likely print a few during the lifetime of the loco.

Lastly, consider a straight axle to an axle with a gear (or teeth rather), its a bit more complex part to produce at such a small scale, even for 3d printing. Though it can be done. To produce a commercial quality gear, you would have to print below 'normal' print sizes.

 

Best of luck!

PMR

 

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Posted by NVSRR on Tuesday, January 5, 2021 4:58 PM
Yes they can be made strong enough. At a price. Right now, to get a 3D part. You have to hope somebody did the engineering cad work already or you have to do. Then send that over to shapeways or others to print it. Then you have to check refine and reprint for corrections. Gets pricey if you don’t plan to set up a sales run with one of these print houses Could you upgrade the whole drive line, not just the universals? No luck on sites like auction of hoswap? Shane

A pessimist sees a dark tunnel

An optimist sees the light at the end of the tunnel

A realist sees a frieght train

An engineer sees three idiots standing on the tracks stairing blankly in space

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Posted by jjdamnit on Tuesday, January 5, 2021 3:26 PM

Hello All,

woodone
With all of the dog bone types of connectors that NWSL has you can build your own dog bone- the sets are not that expensive. Just measure you(r) S.I.C, shaft size and go from there.

Yes, you'd think that would be true.

As I've previously posted, the current NWSL webpage only has written descriptions...

jjdamnit
snjroy You might also want to consider NWSL. Given the volume, it justifies a phone call (I assume they still answer the phone - the previous owner did).

But...

jjdamnit
I looked at their (NWSL) website and was further frustrated by the lack of visual information. I know what these parts look like but the written descriptions were not helpful.

Shapeways seems to be the folks to reach out to and see if this is possible.

MisterBeasley
Being a printing process rather than a forming process, would 3D printed gears and axels actually be strong enough?

Great point!

That's why I'm reaching out to see if a material in 3D printing will be sufficient.

Thank you for all your input and keep the suggestions rolling in.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by MisterBeasley on Tuesday, January 5, 2021 3:24 PM

Being a printing process rather than a forming process, would 3D printed gears and axels actually be strong enough?

It takes an iron man to play with a toy iron horse. 

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Posted by rrinker on Tuesday, January 5, 2021 3:17 PM

 Swap the wheels out with the smaller 40" wheels, since it's a switcher and shouldn't have 42" wheels anyway? Can use Athearn parts, I did an Athearn switcher years ago with NWSL's replacement wheels, which I'm not sure they make any more. Though these were sized to press fit the stock Athearn axle gears.

                                          --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by woodone on Tuesday, January 5, 2021 3:00 PM

With all of the dog bone types of connectors that NWSL has you can build your own dog bone- the sets are not that expensive. Just measure you shaft size and go from there.

I think that I keep 5 or 6 sizes in my parts bin for re-motoring jobs.

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Posted by jjdamnit on Tuesday, January 5, 2021 3:00 PM

Hello All,

I just want to begin by thanking all of you for your great suggestions and invoking all of your knowledge.

RR_Mel
If the older axles are larger in diameter than the 60024 gear you might tr(y) S.I.C. drilling it out and using CA.

I considered this but the amount of material on the newer axels won't allow me to bore out the needed clearance for the older axel shafts without failure of the thinner walls after "machining".

This is why I'm considering, despite the initial price of tooling, 3D printing options.

Thank you for all your input and...

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by RR_Mel on Tuesday, January 5, 2021 2:52 PM

 

If the older axles are larger in diameter than the 60024 gear you might tri drilling it out and using CA.

CA is amazing, I glued a axle gear on my Bachmann 2-6-0 G gauge locomotive back in 2005 and it still works like new.  The locomotive was under warranty and Bachmann sent me a replacement wheel set with the gear but since it’s still working OK it is still in the package.

 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

 

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Posted by jjdamnit on Tuesday, January 5, 2021 2:44 PM

Hello All,

RR_Mel
...to drill out the Shapeways gears and use super glue (CA) on the shaft, haven’t tried that myself.

Thank you for your suggestion.

I'm thinking, even with 3D printed parts, there will be some hand tooling to get them to fit. 

Again, keep the great comments/suggestions coming.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by RR_Mel on Tuesday, January 5, 2021 2:40 PM

I found some Model Power axle gears on Shapeways (about 5 yrs ago) and one cracked as I attempted to install it the other only ran a few hours (over a weeks time) and cracked.  I finally got some that worked (still OK) I think from NWSL.

I read on another forum to drill out the Shapeways gears and use super glue (CA) on the shaft, haven’t tried that myself.

 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

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Posted by jjdamnit on Tuesday, January 5, 2021 2:19 PM

Hello All,

Thank you for all your great responses.

RR_Mel
The Athearn site says preorder, Due late May, 2021. ATH60024

As I posted...

jjdamnit
The wheels press into the plastic axles but the diameter of the O.E.M. axles are larger than anything currently available from Athearn. I ordered what I thought would be a substitute from them but they don't fit.

Unfortunately, the current replacement parts from Athearn are not a viable option.

gmpullman
Have you looked at the A-Line drive shaft parts?

Yes, I have three sets of them and nothing is compatible.

I apologize if I didn't make it clear that I have two separate problems from two manufacturers:

The first is with Bachmann.

It's the plastic coupler from the worm gear shaft(s) to the dog bone drive shaft(s) that has cracked.

This coupler is not available as a separate O.E.M. part.

Bachmann only sells this part in a larger sub-assembly, which is currently out of stock. 

I only need this specific press-fit coupler, not the entire sub-assembly that I have harvested this specific part from, and have a surplus of un-needed gear towers.

The second is with Athearn.

Which is the plastic axel.

The older 42-inch wheels have a larger diameter spindle, that presses into the geared axel, than any currently available replacement parts, is cracked.

I have purchased several replacement wheelsets from Athearn and none of them fit- -adding to the useless parts bin, and lost monies.

This is why I am exploring the options of 3D printing these specific parts.

mbinsewi
...on Shapeway's web site.

Thank you for this suggestion and I will look into this option.

snjroy
You might also want to consider NWSL. Given the volume, it justifies a phone call (I assume they still answer the phone - the previous owner did). 

I looked at their website and was further frustrated by the lack of visual information. I know what these parts look like but the written descriptions are not helpful.

I apologize if my responses are terse and show my frustrations.

snjroy
In all cases, it will not be cheap.

Yes, I realize this. The first run is always the most costly.

But, if other modelers are encountering the same problems, producing in bulk might be a viable cost solution.

I do not want to be a "distributor" of aftermarket components, I just want to run reliable motive power. 

Again, thank you for all your great responses, keep them coming and...

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by snjroy on Tuesday, January 5, 2021 1:54 PM

You might also want to consider NWSL. Given the volume, it justifies a phone call (I assume they still answer the phone - the previous owner did).

In all cases, it will not be cheap.

Simon

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Posted by gmpullman on Tuesday, January 5, 2021 1:40 PM

jjdamnit
It's the plastic coupler, press fit on the metal worm gear shafts to the dogbone, that fails.

Have you looked at the A-Line drive shaft parts?

https://ppw-aline.com/collections/miscellaneous-re-powering-parts

Scroll down.

Athearn SW universals:

https://www.shapeways.com/product/UN6A8NTEG/assembly-drive-athearn-sw7-replacement-driveshaft?optionId=65766288&li=marketplace

 

Good Luck, Ed

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