[ralphbrades]

What will follow is how I design, program and print parts prior to assembly. What I intend to do is describe the process and then illustrate it with photos and then a dump of the code used to produce this part. All the code is produced under GNU GPL 2.0. For some reason the editor for this forum collapses the tabs to just /nl. The code will work -it is just not as beautiful...

This is the target locomotive, I t will be produced in "Gauge 3" which is a scale of 1:22.6 running on 63.5mm track or 13.5mm to the foot.

https://en.wikipedia.org/wiki/British_Rail_Class_22

It is not pretty -to be honest the baby warship is dammed ugly. But this is what I have chosen, there are few diesel hydraulics in this period of BR I use the period of 1948 to 1963 as the era of my railway. This enables some economies such as coaches being "Blood and Custard" and diesel locos being BR Diesel Green. Electric locos are BR Electric Blue -which has to be specially mixed, The BR Rail Blue is a totally different colour entirely!!!

And so we begin!

regards
ralph

 

[fsts2k]

Looking forward to seeing this come together

 

[David Leech]

Ralph,
This will be fun to watch.
A couple of years ago, a friend who was tired of having his Gauge One British trains pulled by a battery powered USA Trains NW2 switcher, asked if I had any suggestions.
I said that maybe I could 3D print a British looking diesel body to fit on the chassis.
Checking the wheelbase of trucks and spacing, I found that the Class 22 would fit.
However, closer examinations showed that the original chassis width was far too wide to look correct, so I ended up making a new chassis too.
The photos show how I only needed to computer draw one cab, and print it twice and then the central body part and the skirts and it was done.
Hopefully your printer will be large enough for the Gauge 3 size that you can do something similar or do you plan on a lot of parts?
Cheers,
David Leech, Delta, Canada

 

[ralphbrades]

David,

I operate by making "tiles" and then epoxying them to a plywood backing board. Thus you could say that I make a lot of pieces. The roof will be made from ten sections. The longitudinal part of the body from six pieces at least. The central body has a distinct facet below the driver door window.

Quote a lot of the bodywork has repeatable objects thus coding is going to be fairly straightforward with lots of "yanks & puts" between the source code files.

The chassis frame is going to be made from 13mm x 3mm thick rhs steel. (Its cheap!) The bogie plates made from laser cut 3mm thick BMS and the axles all powered via a single stage 12:90 MOD0.5 spur and bull gear. (I like simple) from a motor, (see elsewhere). Fitted to a 50mm wheel this equates to a std BR 3'9" express loco driver wheel.

The gears I use are made from POCAN which is a ground glass and Nylon composite. Once run in there is no trouble - but fitting gears with a fine glass saw edge to each tooth is often a bloody task!!!

Regards

Ralph

 

[Scott]

Ralph, I'm looking forwards to this project and learn something new.

 

[ralphbrades]

Well what I do is (I think) pretty simple. The code is very simplistic and like all of the prior projects aimed at a yr9 with access to his schools reprap and a small source of income!

this is the side A of the locomotive. It is made from two slabs that I am in the process of cutting holes into to insert the things like doors and radiators. The top slab is inclined by minus 2.5deg in the X axis to produce the facet line on the bodywork. Once this piece is finished I will dump the code here for you to mangle to your hearts content.

regards

ralph

 

[ralphbrades]

as promised!
//BR class22 SIDEPANELONE.scad

//lower panel
difference()
{
cube([220,60,5]); //side panel to cut out of
{
translate([1,8,-5])
{
cube([3,50,16]); //handrail
}
translate([21,8,-5])
{
cube([3,50,16]); //handrail
}
translate([40,30,-5])
{
cube([30,25,16]); //small radiator
}
translate([120,30,-5])
{
cube([44,25,16]); //large radiator
}
translate([75,5,-5])
{
cube([30,55,16]); //engine door
}
translate([5,5,-5])
{
cube([15,57,16]); //drivers door
}

}//end of holes to cut out
}

//start of things to fill holes
difference()
{
translate([5,5,0])
{
cube([15,(57+30),2]); //drivers door
}
translate([7,(57+3),-5])
{
cube([11,27,16]); //window
}
}
difference()
{
translate([75,5,0])
{
cube([30,(57+30),2]); //engine door
}
{
translate([77,(57+3),-5])
{
cube([11,27,16]); //window L
}
translate([92,(57+3),-5])
{
cube([11,27,16]); //window R
}
translate([89.75,4,1])
{
cube([0.5,(57+29),16]); //door slit
}
}
}


//upper panel


rotate([-2.5,0,0])//facet
{
difference()
{
translate([0,59,4.55])
{
cube([220,40,3]);
}

{
translate([5,58,-5])
{
cube([15,30,16]); //top of drivers door
}
translate([75,58,-5])
{
cube([30,30,16]); //top of engine door
}
translate([40,62,-5])
{
cube([30,25,16]); //small radiator
}
translate([120,64,-5])
{
cube([44,25,16]);
}

}//end of things to cut out}


}
}
//END

 

[ralphbrades]

Well the gcode file from CURA has been fed to the tronxy. According to the sand glasses part one (port) should come off the build plate at 20:35:19. The other side (starboard ) is a simple morror() command.

Doing a 12+hour print is nerve wracking!

But, the part will cost the next builder £0.60p. where possible I like to make a complete model from a single reel of PLA (£10).

Regards
Ralph

 

[David Leech]

The other side (starboard ) is a simple morror() command.

Ralph,
I know that you know this already, but the two sides are different, and not a mirror image.
The doors are in a different place, but a simple command to move them.
Cheers,
David Leech, Delta, Canada

 

[ralphbrades]

Yes you are right the A and B ends are not symmetrical. But rather than recode the entire thing I can simply mirror() the required object to this place.

It is 17:52 and the printer os still at work on the first piece! The plans come from the (now extinct) PDH designs in OO scale, so there has been a lot of work with dividers and a slide rule

[X divide 4 multiply 13.5]= Y

But as I said a lot of yank and put between the files

Regards

Ralph

 

[David Leech]

Ralph,
It's not that they are just not symmetrical, the doors are in different positions on the other side.
Cheers,
David Leech, Delta, Canada

 

[ralphbrades]

David. If you examine the bottom right hand corner of the drawing - it says page one of two. I do have to admit that shot is a nice one to work from. What is still being printed on the tronxy is the section from the end of 'b' to the end of 'd'.

Section 'e' is a standalone.

But if you examine section 'f' and 'g' this is a mirror() of section 'd and ''c'. The code for this is going to laughably simple, additional radiator vents are removed and a control panel cover plate inserted. I will probably do it whilst waiting for my mug of tea to mash.

Regards

Ralph

 

[ralphbrades]

Here is the screenshot of the third panel of the side of the loco. You will notice that it now sits to the minus side of the X axis as it has been made as a positive and then mirror() used to reflect the code. Its a cheat I know!

 

[ralphbrades]

I did not skip a puece -being naturally lazy I did the easy bit first. Here is the central radiator,

 

[ralphbrades]

And now PAGE2!
These is the fourth and fifth slabs. I have been asked why I don't append the code. This is because the only code you would need is in the first dump. and the other slabs simply consist of moving the cutouts around. The re-enforcing piece at the top helps the angled CUBE statement to hold everything together! Yes, I DO use Debian11...

 

[ralphbrades]

I have not been too well so this has paused construction.

But here you can see the six slabs awaiting bonding to the plywood backing. The cab sides are going to be tricky as they have a Y offset of 7° plus the facit X offset of 2.5°...

Some 'A' level Maths will give me the frustrums that sit over the cab ends.

Regards

Ralph

 

[ralphbrades]

now we get to the very boring bid -bur essential of printing the internal frames and support structures for assembly. This is the trapezoidal slab which will sit at the top and bottom of the cab sides. The next are the "frames" that will hold the sides together.

 

[ralphbrades]

As promised. there will be four cabformer plates and four frames printed.The SLA battery will sit in the off central radiator panel position and be slung below the floor level and ride on a stirrup bar this will increase the stability of the loco and cool the SLA during running or charging.

 

[ralphbrades]

Ok... Now the leap into madness. The pignose has the problems of being flat and not a square construction. When I did the Peak it was bad but everything was based on a nice cube with rpunded corners. Here however there is nothing that can be considered "square" unless it is the loco front(!)

Using the mincowski() function I can blende two shapes into a third what I don't know is how many shapes I can blende to produce a result. Time for Sunday Lunch and hopefully the grub will shake something loose as I munch.

Regards

Ralph

 

[ralphbrades]

Well to be honest in the end I came down to accepting that I would have to use a file and car body filler!!! This is the screen dump.

This the program dump
//br class 22 PIGNOSE.scad

//bottom of nose
cube([97,54,5]);
translate([0,-25,0])
{
difference()
{

cube([97,25,3]);
{
translate([-18,0,0])
{
rotate([0,0,-45])
{
cube([25,25,25]);
}
}
translate([97,-18,0])
{
rotate([0,0,45])
{
cube([25,25,25]);
}
}
}
}

}

//top of nose
translate([30,54,0])
{
cylinder(5,30,30);
}
translate([67,54,0])
{
cylinder(5,30,30);
}
translate([24,64,0])
{
cube([50,20,5]);
}


//central access door
translate([35,0,5])
{
cube([30,80,1]);
}

//light discs
//lower centre
difference()
{
translate([50,20,6])
{
cylinder(2,7.5,7.5);
}
{
translate([40,10,7])
{
cube([20,10,16]);
}
}
}

//upper centre
difference()
{
translate([50,70,6])
{
cylinder(2,7.5,7.5);
}
{
translate([40,60,7])
{
cube([20,10,16]);
}
}
}

//lower left
difference()
{
translate([20,20,5])
{
cylinder(2,7.5,7.5);
}
{
translate([10,10,6])
{
cube([20,10,16]);
}

}
}

//lower right
difference()
{
translate([80,20,5])
{
cylinder(2,7.5,7.5);
}
{
translate([70,10,6])
{
cube([20,10,16]);
}

}
}
//END

I manually drill the inserts for 3mm LEDS into the base of the light flaps and the stop lamps.

regards

ralph