Hornby N2 Chassis

[jazzer]

I have been inspired by RM Webbers to start trying some serious work on some poor runners to try to get them as smooth as I can. 
First up is a Hornby N2 which I’ve had for years, never was a steady runner but got worse after damaging the ridiculously flimsy pick ups trying to clean them.

A new Chassis from Peters Spares seemed a good idea and I could check the quartering ( which I was sure must be the route of the problem) while it was in pieces. 
Then the law of unforeseen consequences kicked in.With the motor disconnected the chassis runs along sweetly with a gentle touch of the finger, so as far as I can see the problem presumably rests with the gears. So my questions are:

1. Is it worth while taking the gears out of the old chassis into the new , and if so is it all a push fit ? It seems a bit of a flimsy arrangement and I don’t want to damage the plastic gears.

2.If as I suspect ( guess) the uneven running is due to the gears in some way changing the gear wheels over is only going to replicate the problem ( unless anyone has any other suggestions). I have to say though that on a purely visual examination there doesn’t seem to be anything wrong with either the gears or the worm.

3  Would I be better off keeping the old chassis and rigging up some new pick ups, perhaps by gluing some copper underneath and having some wipers on the backs of the wheels ? Has anybody tried this sort of arrangement ? Or should I cut my losses and see if Mr Wizard has any Comet N2 chassis in stock and while am at it get a new motor ?  The thing with that though is that for the cost of a new. Chassis and motor I could probably buy two more N2’s on eBay, although I  don’t particularly mind the cost if I get a smooth running loco at the end of it .

Ant advice gratefully received.

.,

[DCB]

Is this the plastic N2 chassis which started off as Airfix with a great big motor over the trailing bogie and a huge block of metal as a ballast weight?   If so its truly awful and not worth wasting time on.  I have one here in my scrap box, in theory its becoming an 0-4-4T but in practice it needs brass axle bearings to stop the chassis wearing, which means losing the quartering, and scratch building a brass chassis seemed a better idea.  Comet chassis?

Alternatively measure up a Bachmann V1/V3 chassis. The full size was as far as I know the same wheelbase and wheel size obviously you would have to shorten it and lose the outside cylinders and pony truck.

I would suggest selling the old chassis on eBay but I tried that and no one wanted mine.  

Best of Luck

 

[jazzer]

It’s a plastic chassis. Not sure if it’s the old Airfix design but I don’t think is . It does however have  huge block of metal  in front of the motor and it drives the rear axle. Now you mention it , I doubt whether it would win any prizes for great chassis design.

I’ll see if anyone else has any ideas but thanks for your input , and I am being persuaded to go for a Comet chassis. I am in a better position now to do some chassis building than I have been in the past so that is a skill I am keen to develop.

[34theletterbetweenB&D]

I have several - what with modelling KX inner sub area it is the most numerous class on the layout - and have fettled them as required to obtain smooth running.

 

Trouble spots:

Worm engagement with/and gear train. It's all plastic mouldings and these aren't always true or flash free. You fiddle around with the assembly until the worm lies on the pinion with 'fag paper' clearance and the gears turn freely such that running is quiet. Generally a little shaving away of flash and ensuring the gears are not pinched between the walls of the gear tower does it.

 

The 'melted over plastic pegs' attachment of the pick up  wipers. If they fail, use small self tappers to secure, solder on tags to the wiper strip if necessary to put the self tappers through.

 

The flaky sprung contact between pick up strips and motor on the pre-DCC socket models. Replace with soldered on wire connections.

 

Sprung centre axle, which is feeble. Make and install new spring on the same pattern with thicker bronze.

 

If traction is insufficient, cylinder of lead in the boiler fixes that.

 

Some have needed a soft spring added to the truck to keep it on rails when leading.

 

 

Never had a quartering problem on my half dozen; grease lubrication on the axles, no significant wear yet in the twenty plus years intensive use of the oldest specimens. You can unclip the cab for cabriolet operation in summer, ho ho ho...

 

Would I like a 'current standard' RTR model? Yes please, but a J6, K2, J17, B16, D34, Bugatti front P2, P1and J69 - none of which have enjoyed a RTR OO model - figure well ahead in my personal 'would like' queue.

[hallmodelspares]

It is adapted from the chassis that airfix, which passed through Dapol to Hornby in a deal over toolings. Hornby modified the design and put in the newer type motor similar to the type on a4 etc super detail loco drive model. Repair would be good route to go as they do require work like many older design models do. The gear is worth checking which is located into the frame. Examine it to make there is cracks in the gear which is usually a fault. check also the set on the wheel for condition. If you can hold the wheel still and the gear moves it will need a new wheelset or sets. If you can repair them pickups that should also sort the running

[gordon s]

I’m sure I may have one of the new Hornby N2’s chassis around somewhere. I had two converted to use Comet chassis and I know I sold one. Let me know if you are interested and I’ll have a dig around my wardrobe store cupboard.

[jazzer]

Thanks to everyone that’s contributed comments. I really appreciate it.

 

I have decided to take both routes, as I need to build up some experience in getting chassis to run sweetly and in building them so I am going to attempt a repair and if it doesn’t work satisfactorily.

 

Gordon, thanks for your offer but I have a new chassis from Peters spares that I can fall back on, but if I use the new chassis which is the easiest course, how do I knock the gears out of the present chassis ? Are they just a press fit or are they fixed in some way ? If they are just a press fit I can just swap them over, but if there is a risk if damaging them I will leave them where they are and just fit some new pick ups to the old chassis.

 

Thanks again for all your comments.

[jazzer]

Just to complete the story on this one, having taken on board everybody’s comments, the gear wheels and axle on the new chassis won’t come out so I stripped the old one down completely and rebuilt it carefully, as one would have hoped they would have done at the factory. In particular I took my time in getting the worm and motor properly positioned. I then connected up to crocodile clips and lo and behold ran near perfectly. So, a valuable lesson to me in checking worm/gear settings..

The only thing is the flimsy Hornby pick ups are damaged so I’ll either transfer the others from the spare chassis or rig something up of my own.

Thats given me confidence to try something more ambitious, so thanks again to all those who have commented.

[34theletterbetweenB&D]

On ‎10‎/‎05‎/‎2020 at 13:23, jazzer said:

...The only thing is the flimsy Hornby pick ups are damaged so I’ll either transfer the others from the spare chassis or rig something up of my own...

Very simple technique for plastic chassis, screw in two small self tappers per side on the underside of the chassis, and with the screw spacing established, make a bench jig to form the mounting loops in the wire for the pick ups, and screw onto the chassis. It needs some delicacy to avoid splitting the chassis, off setting the mounting points either side helps.

[manna]

G'Day Folks

 

Another small but vital thing to check is the large weight in the chassis, it connects the pick ups to the motor, and if it's a bit out, the loco will stop.

 

manna