Split Chassis with Romford Wheels

[60526]

I've recently bought the wrong wheelset for a Bachmann split chassis model and a friend has given me a set of Romfords to use, of course the axle diameters are different, so I'm asking if anyone has been down this route before, do you know who sells "adaptor" bearings? So this problem is for one of my locos, but one of the things I do is to give models a MOT for our Newhaven club members or for ones we sell at our show and whilst I can rob one model to get another going properly I'm starting to build up a backlog of Mainline and Bachmann models that have wheels problems, I’ve also been asked to convert 2 models to EM but not with Gibson wheels. Am I right that some Bmann split chassis models over time have had different axle diameters, this does not include the latest Bmann chassis?

[Hatfield Shed]

Brief advice based on several folks experience including my own: give up the idea of using the Mainline or Bachmann split chassis in anything but the form in which it was designed. Wear it out in use employing whatever s/h spares can be got, with 'rescue techniques' such as glueing the wheelsets solid, and dispose of it once worn out by running. Practically everything in the mechanism design and materials choices is short life, and the plastics will often deteriorate on many of the models even when standing unused.

Not seen any adaptor bearings offered, and don't think it a good plan! The castings are not that precise, and the alignment of the chassis halves quite rough and ready, these things 'slop along'. Adding bearings will only make the lack of precision more apparent.

The split chassis axle diameters do vary from model to model, and are typically much larger diameter than on their later steel axled mechanisms, or the 1/8" or 3mm steel axle diameter normal on kit wheels such as Markits.

Options for a repower of a body that may have been significantly worked on: build a replacement etched kit mechanism; use the current RTR mechanism. I usually go for the second, and even though fixing points are sometimes altered have had no significant difficulty so far. The new mechanisms are not sold separately as spares, so to obtain them usually requires purchase of complete models. (The general lack of spares from the Chinese factory produced RTR works in our favour for this approach. People needing spare bodies are in the same boat, so if you are prepared to act as a 'breaker's yard' they will find buyers in time.)

[Atlantic 3279]

Conversion to Romfords can be done, if you are prepared to try an adventure. Steve Kearns for instance (one time of Gamston Bank's team) made a success of it using "nested" sizes of aluminium and/or brass tubing to bush the axleways to take the Romford axles. I believe he ignored the split chassis block's intended electrical function, allowing the tubes to bridge two sides. One motor connection obviously then had to be insulated and a set of wiping pick-ups fitted to an insulated carrier under the main chassis. The main final drive gear obviously has to be cut from the original moulded axle, centre-drilled and secured to the new Romford axle unless you are changing gears (and motor?) too, and if you are going that far then it probably would be a lot easier build a replacement chassis to give more flexible layout of components and more satisfactory results.

[mick b]

Whats wrong with the chassis? If its the plastic wheel muffs Bachmann sell them quite cheaply. Anything else in the Bin !!

[60526]

I'm sure with quite a few clubs that membership is not exactly expanding these days and down at Newhaven we are managing to keep on par at the moment, we've lost our clubrooms recently and now moved into something more expensive but smaller we can ill afford to lose any really, so I'm talking about guys who are coming back into the hobby, looking to get some of their existing models going but have found problems with the plastic centres for the split chassis or in a couple of cases the pin on the end of the axle has just broken off. There are very few of these yet where the wheels are not slipping on the plastic centres, if they are in good condition then loctite normally solves this, but not all of the centre plastic replacements are available. You’re never going to get a mainline loco that doesn't sound like a sewing machine, but I'm finding that for what the guys want the motor/chassis are not that bad, but replacing wheels is a bit hit and miss. The Bmann wheels with the square pin was certainly an improvement but probably due to oil getting in these just fall apart, but I think if you persevere with Bmann chassis you can get some running reasonably well, wobbling models is a pain but with a J39 I found that by not tightening up the chassis screws so tight it straightened it out, had success with a V1 as well. The worst models seem to be the Collett 2-6-0 and Std 4MT, part of the problem with the former might be the piston and slidebars, but Bmann must have known of a problem with the 4MT because there are 2 if not 3 designs of slidebar support?
Anyhow, thanks for the replies, the guys do not really have the option of going to brass chassis, so I'm feeling a bit adventurous and will look into the use of tubing with the Romfords which is probably the answer to the EM gauge conversions, I can't visualise using Bmann wheels for EM, but if they are RP25 profile then they should work with 1mm clearances.