Semi-permanent ways to attach flywheels to motor drive shaft (N Dapol Class 22)

[n9]

I'm after a semi-permanent solution because I fear super glue might make it impossible to remove parts in future without causing damage.

 

Is the answer a tiny amount of superglue? Enough to attach but not enough to break parts should I need to remove the flywheels later?

 

Or something else?

 

 

 

Detail:

 

I'm fitting the flywheels onto a new coreless motor I bought from Tramfabriek on my N gauge Dapol Class 22.

 

This is what the assembly looks like with the old motor:

 

So at each end of the shaft there is a flywheel with a plastic collar that serves as a socket for the worm mountings to plug into.

 

Here's the same assembly with the worms "unplugged":

 

 

And here is the new motor with the flywheels and collars ready to go back on:

 

 

The drive shaft on the old motor is 1.5mm diameter. On the new motor it's 1mm. So brass adaptors (small brass cylinders or bushes) are provided in the conversion kit and you can see those already fitted to the flywheels in the last pic.

 

The problem is that it should (ideally?) be a pretty tight fit for the adapted flywheels onto the shaft, but it isn't. Sven (of Tramfabriek) sent me a picture showing how they should be delicately hammered on. But while mine are snug fit, I can easily slide them along the shaft with my fingers and the worms would definitely slip.

 

Overall this has made me realise I don't have a clue about how much torque a shaft needs to overcome at N scale.

 

Thank you!

 

 

 

I'll end with some other inconclusive ideas that have flashed through:

. Painting the shaft ends.

. Kapton tape on shaft ends.

. A few strands of copper wire twisted along shaft.

. Copydex.

. Paint as glue.

. Get adaptors with slightly smaller holes if they exist.

. Solder. But spaces are way too small for a tip. So wrap a bit of solid core around the soldering iron tip and use the solid core as a tiny soldering tip?

 

I've ruled out knurling and anything requiring a lathe or dismantling of the new motor.

 

 

[Red Devil]

I use a lot of Tramfabriek motors and adaptors, I normally use a loctite thread bond to secure any adapter etc, if you need to remove anything in the future heat will normally break the bond, obviously that's not much use if plastic bits are involved but metal bits it's no problem. To break the bond I either use a soldering iron or a small naked flame. Off the top of my head it's Loctite 638, but I may be wrong as I'm nowhere near the bottle, if using that or similar go sparingly and make sure you don't lock the motor or any other parts up with it.

[Izzy]

You can either use superglue or one of the Loctite thread locking compounds. I use whatever comes to hand. Just be careful to fit the flywheels first and put whetever you use on the tip of the shaft and then slide the flywheels back and forth along the shaft to spread it and lock everything in place. Do it this way to prevent any compoung getting into the motor bearings and locking that up solid, which of course wouldn't be too good.......!  If you ever need to move/remove the flywheels then apply a bit of heat to them, say via a soldering iron, just enough to start the breakdown of the glue joint. Heat will do this to any of them, cyanoacrylate or Loctite (anaerobic) glues.

 

Bob

[n9]

Thanks chaps! So far it sounds like super glue or thread bond might be the way to go, albeit don't think I could heat that up later to break the bond because the plastic collar does go right through the flywheels so the adaptors are sitting right inside that plastic - you can see that in the last pic. So I'm still open to other suggestions if there are any.

[Barclay]

Hi I use Loctite 603 retaining compound for tasks like this. Expands slightly in the presence of metal and locks it in place, but, as described above, can be released with the application of heat.

[n9]

 

Thank you! 603 seems to be 25 smackers where I live but I will get some if all else fails.

 

Currently I'm on my second supergluing attempt, the first one having just not glued. Is it me, or are super glues getting ever more expensive and distinctly less super? This was Gorilla. I'm giving it the full 24 hours this time, having applied a little more than before with a needle.

 

Might be too late this time around, but I'd dearly love to learn of an option that doesn't require heat to remove.

[Barclay]

It is possible to add a kind of knurling to a steel shaft by rolling it back and forth under a fine rat tail file, and this can be enough to turn a slightly loose fit into an interference fit. Motor shafts can be very hard though so I'm not sure how effective it would be in this case.