Airfix 14xx chassis improvement

[97xx]

Thought I'd share this regarding getting the truly dreadful 14xx to work without a complete chassis replacement.

 

I don't need to recount how bad these models are. The wheelset was pretty clearly eccentric on mine also.

 

However, the body is quite reasonable and I was reluctant to bin it, but equally was unsure that it warranted the expense of a High Level or Comet chassis.

 

The good news seemed to be that the axles are 1/8" so the motor gear is transferable.

 

What I have done in essence is to 'reverse' the Airfix design which has:

• Massive play up/down in forward driven axle
• A fixed middle axle with tyres
• A trailing axle with considerable up/down play

 

The consequence, to state the obvious, is that the only wheelset in permanent contact with the track is the (almost electrically-insulated) tyred wheelset, so the whole thing bobs up and down and stutters.

 

My 'design' revisions are:

• Rigid front axle
• Rigid trailing axle
• Front and rear dead square
• Floating middle axle
• Gibson rods

 

My modifications have been:

1. Replace drivers with Markits (so not wasted if I DO go HL/Comet)
2. Broach out front axle slot in chassis to accept 1/8" brass axle bushes - so this will become a 'fixed' axle
3. Install front wheelset with gear pushed onto axle, adding (in my case 2 x 0.5mm ) washers to limit sideplay to minimum practical level
4. Remove trailing axle PB spring
5. Ream out trailing axle slot to accept 1/8" brass axle bushes
6. I then sweated in 1/8" - 2mm conversion bushes - as I bought Markits traling wheels. The originals are 1/8" so you could forgo this if minimising the spend.
7. So trailing axle now also 'fixed'
8. Mount rear trailing axle with wheels into bearings
9. Using either a chassis jig or glass plate, fettle the axle slots in the chassis to get parallel axles.
10. Loctite bushes at this point
11. Broach out rear driver axle slot to allow about the wheelset to have 0.5mm upwards travel from rail contact
12. Once you're sure step 11 has an axle which is now 0.5mm 'up' and level...
13. Drill 1.6mm diameter hole, 2.5mm deep, in the chassis sides at the top of that axle slot to accept an Alan Gibson plunger pickup spring
14. Drop the rear driver wheelset in place, using (in my case 1mm) washers to limit sideplay - enough to negotiate your smallest radius
15. Make sure the ****dy plungers are free and positioned correctly
16. Remove plastic from the Airfix keeper plate across the front driver and rear trailing axle positions to ensure that the plate doesn't apply pressure to the bushes (as even through they're loctited they seem to budge)
17. Refit keeper plate.
18. Solder a wire from the motor -ve to the motor brass magnet bolt - the contact between the PB spring and chassis block was average at best.

 

It seems to work fine now. 

 

Video: https://www.dropbox.com/s/26u7dq3qrwossl9/Airfix 14xx crawl.m4v?dl=0

 

The video is lowish bitrate so if it appears jerky, it's the video not the loco... ...hard to believe I know!

 

Edited February 6, 2021 by 97xx
Added video

[Sophia NSE]

I did this with mine 

 

Got rid of the useless plunger pickups!

 

[97xx]

17 hours ago, Sophia NSE said:

I did this with mine 

 

Got rid of the useless plunger pickups!

 

Yes they certainly are. I've never had much joy with plungers - this being the first example from 40 years' ago, and the second being trying to use them on a brass chassis of my own, where I reverted to springs.

 

People do seem to be good with them and my assumption is that they are most likely to be successful where the sideplay is very limited.

 

My 14xx was markedly improved in pickup when I initially added nylon washers to limit the sideplay - they must have designed it to endure 6" curves with that sideplay on such a short wheelbase...

[Butler Henderson]

The problem with the plungers was that the spring could not handle the  current that the motor could draw; a good way of killing them would be to do a stall current test to work out what decoder is needed for dcc use.

[97xx]

3 minutes ago, Butler Henderson said:

The problem with the plungers was that the spring could not handle the  current that the motor could draw; a good way of killing them would be to do a stall current test to work out what decoder is needed for dcc use.

You beat me to it - looked at one of them and the spring was shot as it had been heat treated - I could tell by the way the coils had compressed fully and set that way.

 

Even after a remag, the motor will draw 300mA and given it was highly likely that only one wheel was ever in contact with the rails that would do it!

 

I am definitely going to replace them - useless design, poorly implemented.

[Butler Henderson]

if you are only going to run it with autocoach you could add appropariate pick up wheels to that.  By inverting the motor the metal spindle fits into the dome making wiring up pick ups on an autocoach or alternative pick ups on the loco easier.

[97xx]

I've removed the 'positive' side plungers and replaced with 0.3mm PB wire.

 

Aside some of the plungers just not working, with Romfords/Markits they occasionally bridged the insulator between tyre and centre on certain corners. The original Airfix wheels, aside having plastic centres had deep tyre backs and so the centre of the plunger is not ideal.

 

Anyway good enough now to actually use it.

[Halvarras]

I bought one of these when they first came out, loved the looks but the running was 'not good' so when scrap chassis started appearing in the 1980s I bought one, cut the gear wheel off the driven axle (it was stripped, reason for scrap status) and used it to replace the tyred wheelset. Like most people I guess I only wanted it to haul an autocoach anyway. It was certainly an improvement but in the end I didn't use it enough to prove that the plunger pick-up were as bad as everyone was saying. No doubt they would have been.......

[Steamport Southport]

On 06/02/2021 at 16:34, 97xx said:

Thought I'd share this regarding getting the truly dreadful 14xx to work without a complete chassis replacement.

 

I don't need to recount how bad these models are. The wheelset was pretty clearly eccentric on mine also.

 

 

I definitely disagree. Fantastic model when it came out and still stands up well today. I've still got two that work perfectly. The only real problem is the traction tyres which aren't needed.

 

 

 

Jason

[97xx]

1 minute ago, Steamport Southport said:

 

I definitely disagree. Fantastic model when it came out and still stands up well today. I've still got two that work perfectly. The only real problem is the traction tyres which aren't needed.

 

 

 

Jason

I would concede it ran OK when I got it and I have fond memories of it being my first purchase of the 'super detail' era - it did indeed look and feel 'fantastic' then. The plungers were quite quickly a bit iffy.

 

I think you've been lucky to have two that work 'perfectly'!

 

Here it is in what must have been late 1970s... It looks as though I may have erroneously applied a running number to the bufferbeam back then!

[melmerby]

Interesting.

I'm with Jason, there is IMHO nothing basically wrong with these locos and I wonder whether mistreatment and lack of maintenace is where problems have come from.

 

I too have two original Airfix 14XX and the only mod is to replace the tyred drivers and fit DCC (and get rid of all that glue like lubricant which IMHO messes up the pickup's operation.)

One now has Gibson Drivers and the other has two plain Airfix wheelsets.

They still have the original plungers which work fine and they trundle around the layout with an autocoach or two quite happily.

Incidentally both were bought second hand at different times a long long while ago.

Nice smooth runners:

 

Loco1 (Airfix wheels) climbing 1:60

 

 

Loco 2 (Gibson wheels) climbing 1:60

 

 

Yes the rods are upside down and missing handrails and this one has spacers to restrict side to side movement

[97xx]

56 minutes ago, melmerby said:

Interesting.

I'm with Jason, there is IMHO nothing basically wrong with these locos and I wonder whether mistreatment and lack of maintenace is where problems have come from.

 

Definitely neither of those - it is in mint condition in original packaging.

 

On dismantling one of the faulty plungers the spring had per above clearly lost its temper, and I definitely had a very wobbly driver which in spite of best endeavours with mill vice and so on would not square up. Another plunger case was simply so loose it kept disengaging from the contact strip.

 

Anyway, to avoid further embarrassment, perhaps I was over-zealous in my condemnation.

 

However, all said it crawls across points at cogging speed without any faltering. Very pleased and it's a lovely little loco.

 

I quite like rescuing these early models... ...or perhaps it's just having the time... see... 

 

Edited February 7, 2021 by 97xx