Climax problem

[dmolavi]

Both my father in law and myself have this same problem w/ our Climax locos, purchased from different dealers. I purchased mine about a year ago, his was purchased just a month or so ago. 

What's happening is that after running around the track for only a couple of minutes, the driveshaft connecting the motor to the bogies is coming loose and starts spinning freely.  this is happening on both the front and rear bogies. 

we are local to philadelphia...is this something we can bring/send in for repair?

[the Bach-man]

Dear D,
Give service a call before bringing it over.
Have fun!
the Bach-man

[Whitty]

I have what seems to be a similar problem with my Climax. I've been testing it on a short length of track for radii and grades but today on getting it out there's no drive to the trucks. The pistons and cranks go around but the loco stands still. I think the problem is where the drive shafts fit the gearbox but being in the UK I cannot pop mine into Bachmann US for repair.  Any suggestions anybody?

George

[rayport]

Check the drive coupling going onto the rear truck. This will often split and thus be unable to power the truck. Both trucks are driven but with so much weight on the rear truck this is the main source of power to the engine. A very small amount of epoxy (in the US I use JB Weld) cured the problem for me. Just be very, extremely, careful to ensure that you apply just enough and do not get it anywhere that it could cause the whole drive shalt to freeze solid. This also works well for the split Shay gears. Provided that you use just enough epoxy to do the job, too much and you will need to buy a replacement engine.

[Whitty]

Thanks rayport. That is exactly the problem. I have discovered on close inspection under a magnifying glass that in fact both drive shaft collars are split where they join the gearbox. Obviously they are not up to the task and Bachmann should be ensuring that a stronger material is used for these parts. I am considering trying to find some fine brass tube to match the collar size (about 2mm. I think) and fitting that over the collar.   Otherwise I'll try your suggestion.
I wonder if Bachmann would supply replacements as the parts are clearly "not fit for purpose".

[rayport]

Don't know why they let the problem persist since it is frequently encountered - but I would note that the solution I suggested does hold up well and the problem has not recurred on my engines after the fix.

[Linzthom]

Hi Whitty,

That is exactly what I did when the plastic collar split on my Climax drive shaft. Plus I had to fiddle around with the smaller beavelled gears that were malformed to get them to work. All in all, a devil of a job.

BUT to their credit Bachman did send me a pair of new trucks when I asked about the problem. And I live in New Zealand.

Lindsay

[Jim Banner]

I am not convinced that the material is not up to the job.  Injection molded gears, collars, spacers etc. that are press fit on metal axles or shafts are the problem.  The holes in them have to be just the right size - too big and they slip.  Too small and they split.

When you injection mold a part, it is normally tapered slightly to make it easier to get it out of or off of the mold.  But for the press fit part to work properly, the taper has to be extremely small or even not at all.  So now there is a problem getting the part off the rod that makes the central hole.  If the plastic is too hot or the mold gets too hot or it you eject the part too early, the plastic shrinks a bit too much and the hole is too small.  If the plastic is not hot enough or the mold is too cold or you wait too long, the plastic shrinks onto the rod, making it hard to remove and also taking a few microns of the rod with it.  Actually there is some loss to the rod even if everything is going perfect.  Sooner or later, depending on how things are going, the rod is no longer big enough to make a hole that is big enough.  So the rest of the batch of gears/collars/whatever are over tight, and some or all of them split.  Even some otherwise good ones may split when subject to extreme low temperature during shipping.  As the temperature drops, the plastic shrinks faster than the metal inside it, about ten times faster.  And to make matter worse, the plastic becomes more brittle at lower temperatures.  Then there is the problem of some plastics becoming brittle with age, so that a piece that can stand the rigors of being press fit on a shaft when new can still split when it gets old.  Sometimes switching to a different, softer material will cure the splitting problem, but the loss of strength may well cause other problems.  In an ideal world, all the parts that might split would be machined from solid material rather than being molded, and in that ideal world, we would all have trunks full of money to pay for them.

So what is the solution?  At a manufacturing level, I don't know.  Maybe incorporating a thin metal sleeve around the collars and spiral reinforcing wires or mesh in the gears.  Maybe drilling/reaming the holes to size after the injection molded parts have cooled completely and aged a bit.  Maybe an exotic material.  They all sound like more money, but maybe that is what we would rather live with.

The solutions that have worked for me have been to add thin sleeves around collars and gear hubs after removing the axles or shafts.  These keep the cracks closed up and usually will even keep the split in a split gear closed up enough for the gear to run smoothly.  Next is to drill or ream out the holes in the hubs or collars so that the axles or shafts will fit with less pressure.  Then after cleaning the holes and shafts to remove all the oil and grease, I like to reassemble things with a drop of ACC or a tiny amount of epoxy.  Sometimes I remove the shine from the shafts so that the will never come out again, but more often I leave the shine so that I can press them back out if I ever need to.  With gears that have no hubs, I have sometimes cut a circular groove in each side (not of equal diameters!) and pressed in some small metal rings.  But I prefer to get new gears, if possible, and drill/ream them to size.  This is a long process that requires making a collet to hold the gear and often a special reamer because there are no drills the right size.  But at least I can then make the hole the size I want, not the size the molding process wants.  What I try for is a light press fit where I can insert the shaft with my fingers but with no wobble.  Then it is time to clean and glue.  I realize this is not the solution for everybody, but it is something for everybody that has a lathe or has a friend who has a lathe, to think about.

Jim

[Whitty]

Hi Lindsay,

Good to know that the idea of using brass sleeve has already been put into practice and works. Now I need to obtain some and try it for myself.  Good to hear too that Bachmann recognise these problems and seem keen to assist.  So far as I can tell only my drive shafts have been affected and not the gears on the trucks, but I'll keep my fingers crossed.  I'll try contacting Bachmann to see if I can get replacements.
NZ is not the ends of the Earth - just one of the nicer parts farthest away, in my opinion, having spent three weeks there last year touring round North & South Islands.  It was seeing the rail-lines alongside many of the roads and across the single carriageway bridges(!) on North Island that rekindled by interest in modelling!

Thanks Jim Banner (your name seems to crop up in lots of places) for the detailed explanation concerning the manufacture and design of the problem parts.  I'm just disappointed that such fine models are let down by weaknesses in their construction, judging from the number of instances I have found on various forums, and not just currently. It seems to be an ongoing problem for modellers across the world.
I wonder if we modellers are expecting too much from the Climax and Shay models having read of the exploits of their prototypes, but I for one do't want them to end up as showcase models!

George