5" gauge A4 Pacific printing experiments

[darrene]

The printer is busy earning it's keep (and using up some filament I dislike ) by printing off some prototyping parts for a steam outline A4 Pacific.

I have a set of Dan Jeavons Pseudosteam frames and a body which I'll build a powered tender for. Rods and wheels are present but the wheels are unmachined and there are some other parts which will be needed so I've decided to see how well they will print - I can use them to quickly visualise the fit of everything and get a test mule stood up fairly quickly.

Here are the frames, wheels and body

The frames are to Don Young's Doncaster design, so with plans-based help from Pete S-H and inspired by choochooenthusiast's fantastic work on his Crab, I've started trying out some printed parts for it;

I've even been tempted to try a wheel, to see how it comes out. I wonder if a set could prove useful in setting the chassis up and to give me a physical reference to machine the steel ones to.

Darren

[darrene]

A bit more progress with the prototyping work.

Trialling a valve crosshead


Main wheels, in sprung, ball-bearing axleblocks

[darrene]

Father Christmas dropped off some wheels which were the right diameter for the Mallard tender!
As soon as the ground bar for the axles arrives, that can start going together - the wheels will be sleeved down to 12mm, to match the diameter of axles and bearings.





I have two 150w motors left at the moment. I’m trying to decide whether to power the tender, which is what I’ve done for the Princess or power a riding car instead which could then be used for anything...

[darrene]

A tiny bit more work on Mallards tender. Please ignore the frame spacer bolts which don't match the countersinking - they're temporary whilst I wait for the correct ones to navigate the Xmas postal system!

It took me a moment to work out why the trailing axle didn't fit within the rear of the pre-bent frames.

It turns out the bends in the frames are incorrect, according to the Don Young plans at least: the first bend is too far back and the angle of the bend not great enough. I've removed the leading bend and am not trying to find someone with a metal brake or hydraulic press, to put the correct bends back in - my flypress isn't man enough for the job it seems!

I also need to find someone with a larger lathe, who might be able to mentor me machine the main wheels  - I've not machined drivers before, also my little myford is too small for the job!