SimonD’s workbench

[simond]

Thanks Rob,

I tried like that, but with the floor. That was very messy, not doing that again
( Actually quite interesting, lots of semi-cured-not-very-well-stuck-together layers, a bit like an underdone lasagne - don’t ask!)

It would be easy to remove the floor and copy your approach, and of course, the subsequent join lines are in the corners inside, so trivial to hide.

You appear to have about 60 very fine supports along the edge. I’d need about 90, I guess, if we assume the absolute spacing is the objective. They don’t look like Chitubox tapered fine supports, did you generate them in the CAD? I think that might be quite easy to do - indeed, probably easier than the Chitubox approach.

I've spent too long on the ‘puter today, need to do something else, but this might be the way to go. Thanks
S

 

[Rob R]

Simon,
They are Chitubox supports, just played around with the settings as the default size sometimes stuck to the solebars.
The floorless design keeps the cross sectional area sort of constant and gives you a chance to fit a styrene/brass/depleted uranium floor as is your want.
As a bonus, print times are minimized.
For a 7mm wagon you may need to put one or two disposable cross members to stop it bowing (in or out) suck and see time.
Have fun.
Rob

 

[Rob R]

Simon,
Have a play with the support connection length (circled red) as well as the other settings.
You can change them whilst supporting so you can use several variations of light, medium and heavy on the one print as required.
ttfn
Rob

 

[simond]

Iteration 926 of N6 loco coal is printing…

Meanwhile at the grubby bench, a step forwards. The laser cut slidebars are soldered together and partially cleaned up - don’t use a blow lamp, it’s far too harsh, indeed, the hot air paint stripper was also OTT for soldering such small parts, so I reverted to a decent chunky bit on the Ersa which is what I should have done in the first place.

Ho hum, it’s a learning curve!

Quite a lot of fitting required to get to here, but I’m quite pleased
as I think this looks quite good. Particularly pleased to see scale width slidebars, rather than the undernourished etchings supplied with the kit.

I think I’m going to redo the motion brackets, in two parts screwed on from the outside, as the one-piece one does not work well with the slide bars soldered to it and then fitted to the cylinders as the cylinders have studs (with nuts) to attach to the frames as you can’t do up screws from the inside. In effect, I can’t assemble it as it is - cue Homer-style “D’oh!”.

I shall consider this further before proceeding.

It’s probably difficult to see in the previous shots but the coupling rods will need to be recessed to sink the crankpin head into the thickness of the rod. The head of the 12BA screw will definitely not fit. I had to do this on my own 1366 so I’m not really surprised.



Obviously all sitting in place, nothing fixed as yet. The flange on the rear of the crosshead needs to go where the washer is…

More soon
Simon

 

[Paul Tomlinson]

It’s probably difficult to see in the previous shots but the coupling rods will need to be recessed to sink the crankpin head into thThe head of the 12BA screw will definitely not fit. I had to do this on my own 1366 so I’m not really surprised.

Simon, Have you considered the "back to front" threaded crankpin bushes from Dave at Gladiator - which replace the chunkier nut (Or screw head in your case)?

Crankpin Bushes - Gladiator Models

 

[Pencarrow]

Iteration 926 of N6 loco coal is printing…

Meanwhile at the grubby bench, a step forwards. The laser cut slidebars are soldered together and partially cleaned up - don’t use a blow lamp, it’s far too harsh, indeed, the hot air paint stripper was also OTT for soldering such small parts, so I reverted to a decent chunky bit on the Ersa which is what I should have done in the first place.

Ho hum, it’s a learning curve!

Quite a lot of fitting required to get to here, but I’m quite pleasedView attachment 207592View attachment 207593View attachment 207594
as I think this looks quite good. Particularly pleased to see scale width slidebars, rather than the undernourished etchings supplied with the kit.

I think I’m going to redo the motion brackets, in two parts screwed on from the outside, as the one-piece one does not work well with the slide bars soldered to it and then fitted to the cylinders as the cylinders have studs (with nuts) to attach to the frames as you can’t do up screws from the inside. In effect, I can’t assemble it as it is - cue Homer-style “D’oh!”.

I shall consider this further before proceeding.

It’s probably difficult to see in the previous shots but the coupling rods will need to be recessed to sink the crankpin head into the thickness of the rod. The head of the 12BA screw will definitely not fit. I had to do this on my own 1366 so I’m not really surprised.

View attachment 207595

Obviously all sitting in place, nothing fixed as yet. The flange on the rear of the crosshead needs to go where the washer is…

More soon
Simon

Great persistence.

But good grief, the bits wot I done look rough...

 

[simond]

Simon, Have you considered the "back to front" threaded crankpin bushes from Dave at Gladiator - which replace the chunkier nut (Or screw head in your case)?

Crankpin Bushes - Gladiator Models

Thanks Paul,

that is my normal approach, but using 10BA rather than 12. It won’t be enough in this case. The top of the rod is really the limit.



This is my 1366, some 20 years old…

 

[simond]

Great persistence.

But good grief, the bits wot I done look rough...

I don’t think they look rough at all. Grubby (despite a scrubbing) but not rough.

what did you glue the depleted uranium in with? I can give it a dose of jiffing and bang it in the ultrasonic, but don’t want to leave loose munitions rattling around the smokebox

 

[magmouse]

Iteration 926 of N6 loco coal is printing…

 

[Pencarrow]

I don’t think they look rough at all. Grubby (despite a scrubbing) but not rough.

what did you glue the depleted uranium in with? I can give it a dose of jiffing and bang it in the ultrasonic, but don’t want to leave loose munitions rattling around the smokebox

The uranium was definitely not glued in using PVA - all the scare stories warned me off that idea. I really have no recollection what I used. Possibly super glue, could have been epoxy.

It has previously been jiffed, scrubbed and soaked but that was more than a few years ago....

 

[mickoo]

Iteration 926 of N6 loco coal is printing…

Meanwhile at the grubby bench, a step forwards. The laser cut slidebars are soldered together and partially cleaned up - don’t use a blow lamp, it’s far too harsh, indeed, the hot air paint stripper was also OTT for soldering such small parts, so I reverted to a decent chunky bit on the Ersa which is what I should have done in the first place.

Ho hum, it’s a learning curve!

Quite a lot of fitting required to get to here, but I’m quite pleasedView attachment 207592View attachment 207593View attachment 207594
as I think this looks quite good. Particularly pleased to see scale width slidebars, rather than the undernourished etchings supplied with the kit.

I think I’m going to redo the motion brackets, in two parts screwed on from the outside, as the one-piece one does not work well with the slide bars soldered to it and then fitted to the cylinders as the cylinders have studs (with nuts) to attach to the frames as you can’t do up screws from the inside. In effect, I can’t assemble it as it is - cue Homer-style “D’oh!”.

I shall consider this further before proceeding.

It’s probably difficult to see in the previous shots but the coupling rods will need to be recessed to sink the crankpin head into the thickness of the rod. The head of the 12BA screw will definitely not fit. I had to do this on my own 1366 so I’m not really surprised.

View attachment 207595

Obviously all sitting in place, nothing fixed as yet. The flange on the rear of the crosshead needs to go where the washer is…

More soon
Simon

3D cylinders, got to be the way forward

 

[Phil O]

Simon,

Those slide bars look fantastic.

 

[simond]

Thanks Mick, quite pleased with them, I’ve done some standard GW ones too.

 

[simond]

Simon,

Those slide bars look fantastic.

Thank Phil, they’re laser cut, two layers, soldered together. Bit fiddly, but I’ve done three more pairs, so I can do the Saddle tank too.

 

[mickoo]

Regarding the wagon 3D, you do need bigger supports at the start of your print, then work to smaller ones further up. If you use small at the start then they will still flex as the rest of the body is printed. BIG supports at the start and nice and dense to give a rock solid foundation for the rest of the print.

Second point, assuming FNG resin, I'll wager you're under exposing, what you see and read on line is bunkum, they're printing for pure speed and if the resin (it's still elastic until fully cured) is not cured enough it will deform and warp.

Third, hydraulics, FNG resin has quite a low viscosity (it works better around 25-26°C) and when the build plate lowers or even the model later on, it generates massive forces (relative to it's size), these produce pressure waves and coupled with under exposed resin result in failures.

If you have a dual speed Z axis then slow it right down for the last mm or so and for the first lifting mm or so, I mean slow it right down, second, go crazy and add a second to each layer burn time, it might actually work finally look at your delay times, that thick ole resin is still moving once the bed plate stops moving, give it a chance to ooze out and stop moving under compression, by the same token, give it a rest before you yank it off the FEP, poor old model doesn't like being ripped off the second the UV light goes out, it's still solidifying so give it a chance to do what it needs to do, then lift off the FEP.

Details toward the build plate will always suffer the most but you can help it by doing a few tweaks.

 

[Phil O]

Simon,

Is that the finish after cutting, or do they need some fettling before soldering? Other than a good clean.

 

[James Spooner]

Iteration 926 of N6 loco coal is printing…

Meanwhile at the grubby bench, a step forwards. The laser cut slidebars are soldered together and partially cleaned up - don’t use a blow lamp, it’s far too harsh, indeed, the hot air paint stripper was also OTT for soldering such small parts, so I reverted to a decent chunky bit on the Ersa which is what I should have done in the first place.

Ho hum, it’s a learning curve!

Quite a lot of fitting required to get to here, but I’m quite pleasedView attachment 207592View attachment 207593View attachment 207594
as I think this looks quite good. Particularly pleased to see scale width slidebars, rather than the undernourished etchings supplied with the kit.

I think I’m going to redo the motion brackets, in two parts screwed on from the outside, as the one-piece one does not work well with the slide bars soldered to it and then fitted to the cylinders as the cylinders have studs (with nuts) to attach to the frames as you can’t do up screws from the inside. In effect, I can’t assemble it as it is - cue Homer-style “D’oh!”.

I shall consider this further before proceeding.

It’s probably difficult to see in the previous shots but the coupling rods will need to be recessed to sink the crankpin head into the thickness of the rod. The head of the 12BA screw will definitely not fit. I had to do this on my own 1366 so I’m not really surprised.

View attachment 207595

Obviously all sitting in place, nothing fixed as yet. The flange on the rear of the crosshead needs to go where the washer is…

More soon
Simon

Simon,

That is looking good, not only from the workmanship aspect but also from your ingenuity in tackling the issues the loco is throwing at you. I’m not sure I would have your patience, and certainly not your skills!

Nigel

 

[Dave Holt]

Simon.
The new cylinders and slide bars look great and a vast improvement over most kit items I've come across in 4 mm scale.
Regarding recessed front crank pins; in 4 mm scale I use modified Ultrascale threaded items. Where they need to be fully recessed into the front face of the coupling rod, I reduce the diameter of the crank pin flange to the minimum necessary to retain the rod, in order to minimise the diameter or recess needed and preserve the outer layer crank pin boss.
Perhaps the same applies to the 7 mm scale Gladiator pins?
Dave.

 

[Ian@StEnochs]

Simon,

Instead of a visible and unrealistic screwdriver slot you can hide the Romford nut at the back of the wheel. The wheel on the left has the crankpin behind the slide bars. The one below shows a mogul with a simulation of the recessed nut retainer on the real thing.
Only disadvantage, and it is slight, is that the rods need to be fitted to the wheels before the wheels go in.

Ian

 

[simond]

Looks good



Lots of supports between sacrificial “shelf” and body edge and solebar seem to have worked



Inside looks ok



Ends don’t look to have issues



But….




Aaargh! It’s never done that before!

Ok, increase the wall thickness by a tenth or two…

I will not let it beat me!!!