SimonD’s workbench

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simond

simond

Western Thunderer
At the Kempton show I made an unwise purchase of a 4031 Achilles class 4-2-2 with tender. It was three-rail coarse scale but the paint job looked ok, so I thought, “that’ll be a project”.

on closer inspection, the build is not too bad but the paint is not as nice as I first thought, so it’ll be “one of those jobs”, and it’ll involve some more experimentation…

firstly, wheels. They’re cast iron, and now approximate an 0F profile. I was turning them when my lathe motor (suppression capacitor) exploded a few weeks back…

as you can see, I have bushed the driving wheels with Tufnol, and I will bore that to suit the axle in due course.

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The tender has now been converted to split axles, using 2mm glass fibre rod and normal (ie NOT 5-minute) epoxy. The plastic blocks are 3DP and they hold the axle halves concentric and at the correct BTB.

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I have also printed the first iteration of the inside frames for the tender, which as you can see, have brass axle bearings. These will be electrically connected and used as the pickups.

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it’s equalised - there is a bogie supporting the front and central axles, which is free to rock in pitch about the crossbeam just abaft the front axle. The longitudinal beam connecting the axle supports is designed to flex in torsion so the axles can accommodate any cross-wind in the track. The bogie can also roll relative to the fixed rear asleep.

Iteration 1 works, but just not quite as well as I’d like. Iteration 2 will have a bit more freedom in pitch for the bogie, and the torsion beam will be a little less stiff. I’ll include mountings for the scoop and brakes, and lugs to screw the footplate/body to it. I’ll print it this week, and then the tender can be on its wheels. The brakes that I did for the Manor tender will fit this one too.

All the printing so far has been FDM on one of the Bambu printers at the office.

Then things get more challenging…
 
simond

simond

Western Thunderer
I seem to be in total scattergun mode at present.

I’ve turned the wheels for the Achilles and am getting to the point where I might start rebuilding it, it’s lurking on a shelf at the moment.

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Whilst I had the lathe out, I decided to see if I could make the last couple of bits to get my Big Big Hymek working. I needed extensions for the motors I had rescued from a couple of HP printers - the also need to step down from 2.2mm to suit the 2mm worm. I was able to turn them and they look ok, so I force fitted them to the motors and then pressed the worms on

The mandrel in the small chuck has a hole that is deep enough for the 2mm shaft that fits the worm so it presses on the shoulder, the other end of the armature shaft is located in a bit of scrap brass with a 2.2mm hole only about 2mm deep, ensures all the push is axial

Intent used the same setup to press the worms on

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Et voila!

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The bogies are 3DP inners with Delrin chain drive (purchased a couple of years back, it seems like hens teeth all of a sudden) and 13:1 Ultrascale gears

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The Big Big bogies have been cut back so they are just decorative.

If I get some good drawings, I guess I could do the CAD and then print something, but I’m in no hurry in that regard.

I’m planning to make it battery RC and I’m pondering building a track cleaner into the central fuel tank. I’ll get it running first, I did the CAD for the bits I’ve just made in June 23…
 
simond

simond

Western Thunderer
Oh yeah, and this

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12" to the foot scale GW Signal Lamp, pretty much dead scale CAD model.

There will be an LMS one at some point, both drawn from the real thing.

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incidentally, if anyone would like to purchase any of these lamps, please let me know. I don’t have prices, but will sort something out.

S
 
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simond

simond

Western Thunderer
Hymek runs very sweetly, pleased with that. Not much to look at, but I will post a video in due course.

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4 18650 lithium cells, and a Micron MR603. There’s a 1.8A polyfuse as an overcurrent protection, the MR603 has undervoltage protection.

It needs lots of tidying up, and I haven’t given it much of a test yet, but it seems reasonably quick, and can spin its wheels. The Micron control allows very smooth low speed too. Time to shave off the moulded handrails and lamps and replace them with wire and LEDs. 3DP drivers’ desks, buffers, fuel tanks, air tanks…

Iteration #3 of the Achilles tender chassis is also a success.

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the leading (on the left) and middle axles are mounted on a flexible “bogie” that rocks in pitch and roll about a fulcrum point just ahead of the leading brake hanger pivots. The beam between the axle bearings is deliberately flexible in torsion, which allows the axles to compensate, and the whole bogie can compensate with the rear axle.

and given that the wheels are cast iron and the axles are electrically split, the bearings can be used as very low friction pickups. The loco bogie might be used that way too. I’ll see how I get on with just the tender picking up at first, as added complexity has to be worth it!

so, a good few days of minutes here and hours there. :)

Simon
 
simond

simond

Western Thunderer
Here’s the Hymek (with cabs and roof loose)


It runs sweetly but it apparently growls, I suspect the chain. I shall investigate whether a tensioner is needed. It’s far less obvious IRL than on the video!

It’s quite quick too :)


Meanwhile, Questions for those wot know:

The train number reporting panel is presumably only lit on the leading end?

There are two “bumps” on the cab front, presumably lamp lenses. I assume that they were red and white? But which way round and did they change colour?

I believe no tail (red) light should show on rear of loco if train attached?

Thanks for any guidance
S
 
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AJC

AJC

Western Thunderer
simond said:
Here’s the Hymek (with cabs and roof loose)


It runs sweetly but it apparently growls, I suspect the chain. I shall investigate whether a tensioner is needed. It’s far less obvious IRL than on the video!

Meanwhile, Questions for those wot know:

The train number reporting panel is presumably only lit on the leading end?

There are two “bumps” on the cab front, presumably lamp lenses. I assume that they were red and white? But which way round and did they change colour?

I believe no tail (red) light should show on rear of loco if train attached?

Thanks for any guidance
S
Click to expand...

Right: marker lights were only ever on after dark (ditto headcodes), and that’s what the bumps are meant to be. You’ll have to refer to photos to know what colour they should be, but never lit unless light engine (for the reds), even then I think BR agreements were that they ought to carry a tail lamp.

Headcode panels only lit at the forward end. And again, only after dark.

Adam
 
simond

simond

Western Thunderer
Thanks Adam,

I might deviate from reality in having the headcodes continuously lit as a visible way of knowing the radio is on

Cheers
Simon
 
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AllenM

Active Member
A Big-Big Train Hymek, now that takes me back a very long time. About 1970 I repainted one into green and converted it to 2 rail pickup by putting replacement brass wheels (Jackson?) in the unpowered end and a suitable resistor to drop from 12 to 3 volts. It was published in Model Railway News, the first thing I had published.
Regards
Allen
 
simond

simond

Western Thunderer
I suspect I read that, all those years back, Allen, but my efforts at that age were somewhat unspectacular.

I imagine the 3V single axle drive might not have been hugely successful either!

I have spent a few hours today on the CAD, the 3D printer is now in action. Could do with some decent drawings!

cheers
Simon
 
James

James

Western Thunderer
Red marker lights in this era weren't used, a separate tail light was required otherwise the train would be stopped.

Older locomotive integral tail lights were very poor - on the Hull mainline we once had a 37 route learner and in ten miles he got stopped four times for no tail lamp! He came back with a separate lamp flashing away on the rear!
 
simond

simond

Western Thunderer
The Hymek is green, the Achilles is sitting on its wheels, and @Arun Sharma thread about Scarabs reminded me that I had a Roxey kit of the earlier Scammell in my stash. Well, one thing led to another, and the Roxey kit is a bit “of its era” so I now have a couple of extra, and rather more-to-scale trailers. The Cab kit is getting the 3DP treatment too, but that’s not going to happen tonight!

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its Christmas Eve, the kids are home, we're off to the pub in the near future, and all is well with the world.

Merry Christmas to one and all!

Simon
 
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