Author Topic: How to fit wheels  (Read 283 times)

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Offline cabbage

How to fit wheels
« on: August 18, 2018, 11:36:39 am »
Help! This is the first time that I have attempted to fix a cast iron wheel to a steel axle as I usually make steel wheels. My standard technique of using green loctite does noy seem to want to work. The joint is "rubbery" and not rigid. My next attempt will be to use epoxy...

What are people doing to fix their wheels?

Regards

Ralph

Offline Spitfire2865

Re: How to fit wheels
« Reply #1 on: August 18, 2018, 12:33:05 pm »
What kind of fit do you have between them? Is it a tight pressfit or slightly loose?
If loose, possibly turn up a plastic bushing to make the sacrificial mating element?
-Trevor Young

Offline Peaky 556

Re: How to fit wheels
« Reply #2 on: August 18, 2018, 01:29:43 pm »
Ralph,
I have not had to quarter wheels but my standard method is that promoted by the late Dave Lowe, ie machine both parts to a very close sliding or light interference fit, using a shoulder on the shaft to define correct B2B, centre pop the journal lightly at three roughly equally spaced points, then press on the wheel. 
It’s simple and effective, and even if you need to remove a wheel, just lightly centre-pop again to give a tiny distortion to the shaft surface.
With enough effort you will be able to twist one wheel relative to the other for fine adjustment, and hopefully it would stay in that position.  I think this would all be ok with an electric model, maybe not with a live steamer and the impulsive forces.
Good luck,
Tim

Offline cabbage

Re: How to fit wheels
« Reply #3 on: August 18, 2018, 02:07:51 pm »
The fit is a "slide in". The wheel sits "normal" to the axle but it has no shoulder on the axle  to rest against. What happens with a steel wheel to steel axle is there is just enough gap to get the compound around the hole then it sets solid in about ten seconds. Here the wheel does not grip the axle and I can push it longitudinally along the axle.  The compound expiry date is 2020.

I have a epoxy glue that will stick stainless steel together, when it works perfectly -it is lovely. However getting the set joint apart to correct a mistake requires a MAPP torch!

regards

ralph

Offline IanT

Re: How to fit wheels
« Reply #4 on: August 18, 2018, 05:33:59 pm »
Loctite 603 will certainly bond cast iron to steel but the joint won't be quite as strong as a steel to steel bond (same goes for brass). However, it should still be good enough for your purposes Ralph. Your "slide in " fit may be the problem - and of course both parts need to be extremely clean (e.g. no grease, oil, cutting fluid etc).

The "cure time" is a function of substrate (what you are bonding), the bond gap, ambient temperature and whether activator has been used. If the Loctite is "rubbery" it suggests to me too much gap or possibly some form of contaminant as Loctite 603 needs the exclusion of air to set properly. Loctite Activator (7471) can be used to set 603 quickly (and apparently can also help set 'over-sized' bond gaps but I've not tried it myself [yet]).

Not knowing the 'context' of your model's axle/wheels it's difficult to suggest a fix - if it's a simple wagon/bogie type axle for instance - I'd suggest making new axles from slightly larger material (easier than enlarging the wheel bore accurately) but I suspect you are doing something a bit more complex.

Regards,

IanT
Nothing's ever Easy - At least the first time around.

Offline cabbage

Re: How to fit wheels
« Reply #5 on: August 19, 2018, 10:44:39 am »
I nabbed some accelerant from a friend. It has set like rock!!!

Regards

Ralph

Offline IanT

Re: How to fit wheels
« Reply #6 on: August 19, 2018, 10:51:25 am »
Well done Ralph - a good result!    :D

Regards,

IanT
Nothing's ever Easy - At least the first time around.