The worm gear is leaving a gap between it and the cog wheel linked to the wheels. Do you have any ideas as to how to close the gap?
If I remember correctly the motor is held in place by a small screw. This may have come loose which may allow the motor to lift, or alternatively slipping a thin bit of plasticard under the rear of the motor will prevent the front of the motor from lifting.
There is another thing to consider though. Some of the Bachmann 0-4-0 chassis have a plastic framed motor which can fail allowing the motor shaft and the worm to lift despite the motor being firmly fixed to the chassis. If this is the case then it may be possible to repair the motor frame with the careful application of superglue, but the other alternative would be to re-motor the chassis. Nigel Lawton did a kit but I think this has been out of stock for some time, and I can't think of anything else off the top of my head, though one of the motors that Tramfabrik sell might do the job, though you would need to fabricate a suitable cradle. Also, don't forget to remove the Bachmann worm for re-use on the new motor.
Many thanks for your ideas
The motor is plastic.
You may well find that the adessive that glues the upper and lower sides to the front plate has failed out of sight in the chassis cradle.
Also, the rear bearing for the motor shaft is plastic and can get melted with heat allowing the shaft to move up and down.
The way the chassis are fixed to the body is critical as the plastic chassis can and will distort when left under tension for some time.
Cutting away the rear part of the chassis that forms the motor cradle will give problems.
Sadly, this is what is required in the (ex-Meridian) Narrow Planet O&K plantation loco kit!
I have only seen a couple of these locos that run really well as a result and one of them belongs to Pete Wilson!
You can see why these Bachmann locos were so cheap when they were in production!
Brian Meldon
Brian - it looks as if it the long term it is best to replace the chassis
Quote from: Michael Hammond on September 05, 2019, 20:52
Brian - it looks as if it the long term it is best to replace the chassis
The problem is that there is no direct replacement.
The motor in the N drive chassis sits higher and is longer than the motor in the Bachmann chassis.
The result is that it does not fit at all in some kits, in others they require a lot of work and in most it makes the body sit obvioulsy way too high above the rails.
It can be done using the N drive chassis, but sadly it is far from ideal in any of the 009 kits designed for the Bachmann chassis.
Brian Meldon
Whilst Brian is right to say that kits designed for the Bachmann 0-4-0 will need to be modified to take the N-Drive 'replacement', and that there may be the odd one or 2 where such modifications are not possible, my feeling is that such modifications are not beyond the skills one would need to be able to build the kit in the first place.
I've got three of the Chivers / Five 79 Woolwich Avonside locos in my eclectic collection. One was built and fitted with a Bachmann chassis, one built onto an N-drive chassis and the third built to go on a Bachmann and ran on it for a time before being modified to fit an N-drive. I must admit that I find it hard to remember which is which without turning them over to look underneath, but recall that it was easier to modify the unbuilt compared to the finished loco body.
Generally the N-drive will be a much longer-lasting chassis and may well run better as well when compared to the Bachmann 0-4-0 as it avoids the issues (plastic motors breaking, split axle tubes) found in Bachmann chassis (and not just the 0-4-0 but similar vintage 6 and 8 coupled chassis too!), and whilst it may need a bit of extra work to a body / kit to get it to fit it will probably be worth the effort.
What body (built or kit) do you have the Bachmann chassis under Michael?
it is under a Chivers body, I believe it is aRC34 but it was purchased ready made from the 009 sales table. I have had to replace one chassis ready.
Quote from: Michael Hammond on September 08, 2019, 22:26
it is under a Chivers body, I believe it is aRC34 but it was purchased ready made from the 009 sales table. I have had to replace one chassis ready.
The RC34 'Edward Thomas' kit is one of those that needs a lot of work to sit low enough to the rails when using the N Drive chassis. I am not sure if it can be done with a ready assembled kit?
Others may know more.
However, if you are happy with the loco sitting way to high then it will not be too difficult to fit the N Drive chassis.
What was wrong with the chassis you previously replaced in this loco? Did you keep the remains as a source of spares?
Brian Meldon
If it is the motor rather than the chassis itself it might be worth considering the Nigel Lawton remotoring - that is if it is still available. I didn't spot it takinga quick look but ask Nigel.
http://www.nigellawton009.com/BachmannCradle.html (http://www.nigellawton009.com/BachmannCradle.html)
If you are replacing the chassis, don't chuck 'em away as there is sure to be someone who can work their magic to get them working or use them for spares
If I recall correctly that's the Talyllyn Edward Thomas (ex Corris No. 4).
If it is anything like the Meridian kit for Corris No.4 then this may be one of those times that the slightly taller motor of the N-drive chassis is a problem, as by the time you have removed enough metal from the underside of the firebox casting there will not be much casting left - maybe not enough to support the weight of the ends of the loco - and may need to be replaced by a suitable bit of brass tube. However it isn't a conversion that I have done, so just because I can't recall seeing one (& haven't done one myself) doesn't mean that it isn't possible!
The issue with these Bachmann chassis is that they were designed with a low unit cost in mind rather than for longevity. One problem is that the hollow axles split because of incorrect tolerances between it and the stub axles that fit within the tube. This results in drive not being transmitted to the wheels, throwing the quartering out, or the slightly wider gap between the teeth on the gears caused by the split throwing the meshing out and locking everything up. This can fairly easily be sorted out using a pair of replacement axle muffs from N-drive Productions (iirc they cost
Quote from: GraemeD on September 09, 2019, 08:56
If it is the motor rather than the chassis itself it might be worth considering the Nigel Lawton remotoring - that is if it is still available. I didn't spot it takinga quick look but ask Nigel.
http://www.nigellawton009.com/BachmannCradle.html (http://www.nigellawton009.com/BachmannCradle.html)
If you are replacing the chassis, don't chuck 'em away as there is sure to be someone who can work their magic to get them working or use them for spares
The Nigel lawton replacement motor kit is no longer available and has not been available for almost 10 years now. This is because he could not get the special shaft adapter and extender required without ordering several tens of thousands as they are not a standard size and require turning.
If you contact him he may have some of the etches and motors, but without the shaft adapter, or access to the equipment needed to make one, these will be of little use.
Brian Meldon
That's a pity. They were nice kits.
To Brian, Julien, Graeme
Many thanks for all your useful comments, the best way forward would seem to be to create a chassis that works from all the parts available.
Quote from: Michael Hammond on September 09, 2019, 17:23
To Brian, Julien, Graeme
Many thanks for all your useful comments, the best way forward would seem to be to create a chassis that works from all the parts available.
Yes that may well be your best way forward.
N drive sell the axle mufs/gears. But to fit them the chassis has to be taken completly apart.
Brian Meldon