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Discussion Starter · #1 ·
My old a well used Aster Baldwin 0-4-2 has suffered the usual driving wheels slipping on the axle and I have "loctited" them once but due to heat they slip out of quarter again over time so I am considering "pinning" the wheels to the driving axle. So has anybody done this and can you give me some advice. I thought of drilling into the back of the wheel on a shallow angle say 20 degrees off vertical ( use a machinists angle vice to hold it maybe?) and only part way into the axle or drill from the front, parallel to the axle, but that looks a bit ugly.
Any ideas welcome and someone must have done it as some early Asters had this problem with 'alloy' wheels coming loose on the driving axles namely the Baldwin 0-4-2 and the 0-6-0 tank engine with the oscillator motor.
What material do I use for the "pin"? Should I use a grub screw instead? Any tips on drilling the much harder axle with wheel in place? Or should I just give up and get some new wheels cast from Walsall on their square ended axles for easy quartering?
The pic below is the main driving axle with the slipping wheel removed all ready to re-assemble in a quartering tool (use loctite again to hold in quartered position then I hopefully pin wheels to the axle).
Russell
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Hi Russell,
Can you file or mill a flat on the axle, or one each end at 90 degrees to each other? If you use a grub screw that will help.
Maybe you can drill horizontally through that small hub and insert a rod that will align with the flat? Or put in the grub screw you mentioned?
 

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Russell,
It's many many years ago that I did this for someone.
IF I remember correctly, the ends of the axle have a recess, so I drilled through that at an angle into the wheel, and then used a suitable diameter steel pin cut off and punched into place.
I could be wrong about the recess, and may just have drilled anyway!
Cheers,
David Leech, Canada
 

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I know of at least two Chapelons which have had this desease, with as an added bonus the insulated tire also coming loose. It is apparently because the driver centers on many Asters are made of Zamac instead of cast iron as they should be. David's solution should lead to a good repair for the former at least. I used green loctite on my repairs to both problems on mine with success so far. It happened when I was running on indoor layouts in Switzerland. perhaps with outdoor weather, it should keep those wheel centers sufficiently cool. Cross your fingers...
 

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Discussion Starter · #5 ·
Thanks everyone, I thought you three would be the first to chime in on this one. Simon I am saddened to hear the Chapelon Pacific also suffers wheel slip/tyre slip problems so I'll keep an eye on mine and maybe put some more insulation around the firebox and frames, so far so good on my favourite locomotive.
Back to offending 0-4-2 , when I get enough courage I think I will drill on a shallow angle from behind and press in a pin. I am not game to thread the hole for a grub screw but that is probably the best idea Pete and as you say at least on a machined flat or indent on the axle as it can easily be disassembled if need be in the future.
David the axle ends do have a little recess that I use to centre the axle in the quartering tool so that's an idea if drilling from the front.
Hmmm, I'll let everyone know what I do but don't hold your breath guys as I might think this one out for very long time.
Any other advise, warnings or ideas from anyone else most welcome.
Russell
 

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Discussion Starter · #6 ·
New idea now, I just had advice to maybe bore out the wheel boss to enable a bush to be made to press into the wheel that can then be pressed back onto the axle, with use of Loctite again but the press fits should be now firmer than the push fit of the current wheel.
The cast 'alloy' Aster wheels I have been advised may get a bit brittle as they age and may crack or not drill clean if drilled for a tiny tight fit pin. Hopefully boring the boss out is easier.
So any engineering types out there like to comment and give advice to a non engineering person who will probably do the boring on my little rarely used lathe and make the bush myself, but what wall thickness of a bush and at what 'push fit' tolerances? Would this work and hold the wheel or better to attempt to pin the wheel?
Thanks in anticipation of suggestions and comments
Russell
 

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I think a stronger press fit is much more stress on your cast drivers than drilling a hole.

One is removing metal, the other stretching it. To me it seems clear which will stress the cast driver the most.

Pin it, no offense, get your hardened metal drill rod (for the pin) and drill.

Greg
 

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Discussion Starter · #8 ·
Ok after much thinking I thought I would give "Loctite" another go to fix the wheel and if that did not work then definitely do a pin job, but if this holds well all is good. The 'gap' as best I could measure between axle and wheel was approximately .05 to.1mm. So here is what I have done.
I contacted Loctite and after discussion of what I was doing and the hot environment it is in, they said I used the wrong Loctite to start with (I used 641 on a wiped clean surface not properly cleaned ) and to properly clean, inspect and clean again the surfaces then coat both with a primer.
The best Loctite for the application they say is Loctite 620 that is meant to be gap filling, has a high temperature rating of 200 degrees Celsius, it is more thixotropic and will fill gaps up to .25mm with a much higher strength than the 641 I originally used and to use the Loctite Primer SF7471 before application of the 620.

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So now I have cleaned the surfaces many times with solvent and inspected under magnification so now much cleaner than a wipe with a dodgy old rag like I did before. I sprayed on the Loctite SF7471 primer and let dry for 5 minutes as instructed then applied the thick 620 to both surfaces (I had around 3 minutes to get the wheel on and quartered) and wiped off any excess. They suggested I place the assembly in an oven at 50 degrees Celsius for 40 minutes to aid the cure but cure will also happen at warm room temperature over 24 hrs anyway but maximum strength is after 72 hours.
I am told that anything I can do to limit the heat (especially naked flame) would be good so I have made up some better heat shielding for the small burner wicks out of brass to better protect the axle from heat. That was quite an origami job folding up one piece of brass sheet for two burner shields as I did not want to solder extra bits on. This one piece longer shielding for two wicks was held in place by the existing plate that bolts to the frames.
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I will now assemble the loco with some more ceramic heat material around the heat shields and frame then run the engine for a time, over and over again for a few hours running to see if it holds. Last time it let go on the third steaming but it was hauling a "slow-mo" wagon and train so that put a lot of strain when going slow around the sharp four foot radius curves.
Anyway I will let everyone know if it works and I learnt why there are so many versions of Loctite and it pays to consult the experts.
Russell
 

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Well done Russell.
But what about the front axle?
I seem to recall having to do all four wheels on the one I fixed.
A friend in 'the business', was always quoting me different Loctite numbers for jobs he was working on, and until I looked, I never realised that there are so many different types and uses.
Thank you Loctite.
I feel sure that you will have no issues in the future.
All the best,
David Leech, Canada
 

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Discussion Starter · #10 ·
David, I thought about the front axle but since that has never given trouble I thought I would "let sleeping dogs lie" as I think that with the slop in the coupling rods they sort of go around for the ride rather than transmit much traction. Also the front axle removal is quick and easy access if anything happens with no valve gear to disassemble.
So after I get my old brain right to re-time the valve gear again it's fingers crossed when I run it.
Russell
 

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Good advice from loctite
When I use the Fiberfrax insulation, i usually place a thin sheet of stainless between the insulation and heat source which reflects much of the heat and keeps the insulation from getting burnt
 

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Discussion Starter · #12 ·
Good idea Bill, I'll find some stainless sheet and see if I can fold some up. The wicks are tiny and when running the flames are small, good steamer though, but as you suggest less heat through the frames is best.
Russell
 

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Discussion Starter · #13 ·
Hey all, thanks for your advice , I have now finished Loctiting and quartering the wheel on the Aster Baldwin and I ran it for over an hour today and no problems. I took a leaf out of 1:1 driver practice and kept feeling the heat on the axle to see if it was getting overly hot and it remained only warm to touch. So with using the right high-temp Loctite and better heat shielding I think my problem is solved.
I have just posted a short video on MLS of the Baldwin running today along with my Aster Krauss so have a look. The Baldwin even after all the years and use it has had still runs well and has the noisiest exhaust blast of all my locomotives.
Russell
 
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