14xx Frustration..

There’s a bit of an Irish answer kicking round with this one, in that if you want to finish up with a good chassis, I wouldn’t be starting from here. When buying a model for use, my primary concern is that it runs well, cosmetic and detail variations I can attend to relatively easily, but the core function is the model has to move, and move smoothly throughout it’s realistic speed ranges.

DJM Hattons 14xx H1410

Having test run the Hattons/DJM 58xx above, I wasn’t over enthused with it. In original spec the coupling rods were way to large and moved around the crankpin, with an elliptical motion that was clearly visible.

DJM Hattons 14xx H1410
Original Rods vs Alan Gibson 4M75 fitted replacement

One thing I felt worth tackling was the coupling rods, and bought a set of Alan Gibson rods (4M75) to try out. Part of the running trials indicated that running on downhill grades the mechanism had a tendency to bind or lock. This occurs when there is either a load pushing or pulling the locomotive. I took a small bit of video of mine in action on a Woodland Scenics 3% gradient.  DJMhattonsincline.14xx All main testing has been done with a Gaugemaster ‘W’ controller in DC. The binding and cogging still occurs in DCC mode having briefly tried it.

I’ve been working on the ‘big’ plan again and one ruse to extend running time between locations I’m considering is an external track behind the scenery. To maximise this and minimise the visual appearance I’m hoping to drop the track level and hide the extra mileage at the back of scenic sections. To do this, models have to be able to climb and descend gradients reliably, hence getting the Woodland Scenics ramps to try them out. Well as you can see in the filum the chassis binds when any load is applied when descending. As the J94 does the same, ( DJMJ94 chassisprob ), I’ve tried six of them, there must be an issue within the gear train assembly or design, or both. This effect happens with a load ‘pushing’ downhill, as well as in front of the engine, ‘pulling’ it downhill.

DJM Hattons 14xx H1410
Square axle stub

 

Intriguingly the chassis doesn’t bind when decoupled from the body and is freewheeling with either original rods on or off. DJMhattonsrodless14 The first job was to contact Colin at Alan Gibson alangibson to get a set of 4M75 coupling rods suitable for a 14xx, and solder them together. They arrived promptly and I assembled both pairs and reamed out the crankpin holes to fit. Well, sort of. I did one and took too big a bite clearing the second hole and bent the rod. The second job was to contact Colin at Alan Gibson alangibson to get a set of 4M75 coupling rods suitable for a 14xx, and solder them together. They arrived promptly and I assembled both pairs and reamed out the crankpin holes to fit. Lesson learnt! The chassis as delivered has a significant amount of play in the coupling rods, this leads to one axle moving independently of the other if the crankpin holes are not aligned to give a perfect ‘drive’. This is noticeable and sometimes when stationary means the rods aren’t parallel which looks, and is, wrong. With the chassis free running my hope was that fitting the Gibson rods would remove the slack in the rods and drive train. It did, but resulted in the gear train binding. There are clearly points where the gear train will interfere with each other without significant lateral movement on the crank pin. This is poor quality engineering if the gear train jams when fitted with correct, properly fitted coupling rods. The quartering is fixed on these, there is a ‘Romford’ type stub axle fitting which means that unless you are deliberately trying to force the wheels into an incorrect position, they will quarter correctly and accurately. The gear train is clearly part of the drive problem so the logical move is to remove part of the gear train and let the rods drive the unpowered axle in a conventional style. This was the next step which meant quite a bit of disassembly, this model isn’t designed to be maintained in a cost effective manner.

Wot I dun to fit the Gibson rods.
Undo the vac pipes which clip into the buffer beam at each end.
Break the glue fixing of the injector pipes at bottom of cab steps.
Twist and remove front sanding pipes.
Undo three screws, one either end of chassis behind drawbar and one in centre underneath the cab.
You can now pull the body away from the chassis, caution, it is still connected by the motor wires. (Hint) Easier to unsolder them now. Leave the body upside down so you don’t break the rear sandbox pipes.

Remove coupling rods, fixed with hexagonal head screws.
Lever off the baseplate using small screwdriver, its held on by six clips, two either end of the chassis, and two behind the centre drivers.
Remove wheel from leading axle. Using a flat cross section ‘tool’ gently lever the front wheel off from the axle. This gives you access to the screw at the front of the chassis which is otherwise inaccessible due to the wheel….
Undo the three side screws and gently lever the chassis apart. There will just be enough room to remove the second from front free running gear wheel. (If there isn’t remove or loosen the centre drive axle wheel). Removing this gear will leave the front axle independent of the drive train. Caution, check all the remaining gear train has re-seated in their axle drive holes as you push the chassis back to reassemble it. Make sure you quarter the front drive wheel to the centre axle on reassembly.

Hattons 14xx 48 xx 58xx

Fit coupling rods and check chassis is free running with no binding If there is, just open the crankpin holes with a reamer to get a little extra clearance. Once the chassis is running sweetly, fit the rod retaining nuts. Note there is still a large amount on clearance on the crankpin due to their length, I may try and get some washers turned to minimise this, I’ve not yet checked viability of shortening the existing pins.
Re-solder chassis to motor wires and fit chassis to body including three screws to hold motor and body so gears/worm will engage.

Caution ( ask me how I know…), its easy to get a motor wire entangled with the worm leading you to think a wire is adrift or motor has failed, gearbox jammed, all of which you can’t see. If the chassis runs refit the vac pipes and sanding pipes.

Million dollar question, ‘Does it run any better without the cogging?’ In short, no. It does have a very slight improvement in the running and certainly in the appearance, but it doesn’t solve the bind or cogging descending a gradient under load. This means that if you have gradients unless you opt for a full replacement chassis this binding will continue. For me, this points to an incompatibility in the worm gear to tower gear drive components. What that means for the longevity of the chassis components and motors is anyone’s guess, but its not likely to be positive. The next model for release with this type of geartrain is Kernows 13xx family, and inspection of an EP at Stevenage this year showed a slotted crankpin hole in the coupling rods. I hope they don’t have the same problems if using the same style drivetrain.

It’s interesting that online comments and videos indicate no problem with the chassis on gradients under load, but apart from mine above, there are no comments or tests of this model (to date) under load, coming downhill. I find that odd, and to get a sweet running chassis in all modes of operation, I’m convinced this design isn’t where I’d be starting from…

woodlandscenicsSET/page/1

 

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17 Responses to 14xx Frustration..

  1. maxfees says:

    Well if nothing else the improvement in appearance was worth the effort. I think I might be investing in the High Level chassis.

    • bawdsey says:

      James, that’s a lot of money for a body in effect. I’m unable to remove the motor from mine, I can’t work out how to, otherwise there’d possibly be an option of reselling the DJM/Hattons chassis to someone who would want it.

  2. Phil says:

    Thanks as this is saving me around £90 on a 14XX i had pre ordered but do not need immediately. I think I shall leave my order and come back to a 14XX when the time comes that I could do with one. I suspect thetre will be a fe floating abouty in a couple of year’s time.

    • bawdsey says:

      Worth looking at closely before making the jump. I doubt I’ll buy any more, partly because they weren’t common in FoD and also because I want and need better running overall.

  3. Simon Stevens says:

    A few things to check:
    1. Are the axles parallel?
    2. Are the coupling rods matched to the coupled wheelbase? (when building a chassis, you typically make the rods first and use them as a jig to set the wheelbase)
    3. Is the crankpin throw the same on all wheels?
    4. Is the quartering correct, even with the square acles?

    With all these factors correct, there will be no need to make it sloppy.

    Hope this helps.

    • bawdsey says:

      Hi Simon
      Your comments are all good and the sort of things its easy to check when building an etched one. Unfortunately with the construction/design of this ready to run chassis its extremely difficult and time consuming to get it apart to be able to check things like are axle holes parallel. The chassis as far as I can tell is ‘square’. It sits flat on a pane of glass, crankpin throw looks the same using a very basic check of the wheels top centre and laying a steel rule horizontally from pin to pin, and a camera spirit level on top. Not exactly scientific, but shows the basics of the wheel crankpin correlation geometry. The original rods aren’t matched to the wheelbase, apart from they hang on the crankpins, they don’t provide any meaningful drive, see the pic with the oval holes. The quartering would be really difficult to get wrong due to the axle ends, they are a positive location. You could twist them out of quarter once fitted, that would take real noticeable physical effort.

  4. otcm says:

    That has to be the longest winded process ever encountered to take a chassis to bits, surely! Worth doing though, the factory rods look utter tripe…

  5. kaneclements says:

    Hi Paul

    Do you know if there is any evidence that this is a common problem with the DJ 14xx? Or did you just get a duff one? The J94 sounds like a bit of a problem as well.

    I am reticent about buying locomotives mail order as I have been caught out a couple of times and it is a pain to do a return. And at what point is it no longer OK to do that. If after ‘running in’ the thing is still pants does that then mean a repair rather than an exchange or refund.

    Having been caught out with a Kernow / DJ Beattie Well Tank which I returned, when it came to my purchase of an O2 I took the trouble to visit them personally. That entailed a day off and a train journey, but it was worth it to make sure I got a good one.

    Going back to the post, you make very valid points about the design. I want to return to a point I made in response to your original review. Is there an issue with quality control, as well as design?

    Since I returned to the hobby the only manufacturer who seems able to consistently produce really good runners straight out of the box is Bachmann / Farish. (I have only bought one Heljan product, so that isn’t a fair sample and in any case ran brilliantly from the get go). I have had variable experiences with Hornby, though to be fair largely positive.

    And if there is a high return rate to Hatton’s then surely that must be a potential warning sign to other potential clients of DJ about who they commission to produce locos.

    Lastly I’m grateful for your review and update because as a warts and all account of the models shortcomings you have saved me a hundred quid and quite possibly a load of pain and frustration.

    • bawdsey says:

      I don’t think I got a duff one. I’ve already started modifying mine so it won’t be going back. As far as returning one goes the customer deals direct with the shop, and talks to them. I don’t think it’s QC as such, if they are only ever tested on flat track they’ll likely pass the assembly/running test. The binding should be found in the R&D phase much earlier on in the development.

  6. renegourley says:

    Could it be a longitudinal thrust on the worm being born by the motor rather than the ends of the gearbox?

    • bawdsey says:

      Hi Rene, good to hear from you! I think you’re on the right lines there.
      A/ The chassis runs as provided, but binds under load down hill (all gearing/rods as supplied) / DC power
      B/ The chassis runs as provided, but binds under load down hill without the original rods fitted / DC power
      C/ The chassis runs, but binds under load down hill with original rods and one gear drive wheel removed / DC power
      D/ The chassis runs, but binds under load down hill with replacement rods and one gear drive wheel removed / DC power
      E/ The chassis runs, uncoupled from the motor worm with/without original rods / unpowered
      F/ The chassis runs, but binds under load down hill uncoupled from the motor worm with replacement rods / unpowered
      G/ The chassis runs, uncoupled from the motor worm with replacement rods and gear wheel removed / unpowered

      So the interference appears at two points, if you have correct length rods fitted and full gear train the wheels bind as though there’s a quartering problem. Remove one gear train wheel so the gear train is conventional, it runs very well indeed, whichever rods are fitted. If you then put that chassis into the body with motor the bind re-occurs regardless which rods you have fitted or unfitted. I may try to see how much longitudinal float there is on the drive shaft, I don’t recall any. The chassis works ok on the flat and uphill, its only the downhill phase that it trips up on.

      • renegourley says:

        Oh, I hate when there are actually multiple problems! It makes it so difficult to troubleshoot. Don’t forget to look for bent or misaligned crank pins too.

      • bawdsey says:

        The crank pins are quite sturdy items, once the chassis is uncoupled from the motor and leading drive gear removed, it runs properly with the replacement rods. So I doubt the crank pins and quartering are at fault.

  7. Ivan says:

    The elliptical rod holes are commonly encountered on HO European steam models too. Never a good idea. I can sort of see why DJM decided that the driven axles should be linked by gears (it’s done on diesel bogies), but I don’t think the method works well if you have rod-coupled wheels.

    Is it possible to remove the intermediate / idler gears linking the axles, and then see what happens when drive is taken up by the coupling rods only?

    • bawdsey says:

      Hi Ivan
      I have removed part of the gear train, as outlined in the above post. The improvement is marginal in terms of running but the Gibson coupling rods look better, so I’ve left it driving from the replacement rods. It runs ok on flat track and climbing gradients. Haulage power on the flat is again satisfactory for the prototype, I’ve jigged up extra weight over the cab with no real benefit, a slight uphill improvement, and no improvement on downhill running (it still binds), weight distribution sort of follows the prototype, with the leading drivers carrying the least weight. Not a model I’d readily buy again.

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