Improving the Hornby APT (1980s version)

[RedDwarfIV]

 

Prototype bogie. A few adjustments are needed before I start printing these things out en masse.

 

- Reduce connector width to fit in its place on the main part, because currently it doesn't. (It does, however, fit perfectly into the socket.)

- Increase connector and socket height by 0.5mm, to match with original Hornby bogies.

- Increase internal width to accomodate the wheels. Unlike the Hornby parts, these 3D printed ones are too stiff to bend while inserting axle.

- Change height of wheel mount. Currently too low and doesn't stick out like it should.

- Add suspension detail.

 

But for a first try it looks pretty good, and comes with none of the issues that resin casting did.

[GordonC]

 

Prototype bogie. A few adjustments are needed before I start printing these things out en masse.

 

- Reduce connector width to fit in its place on the main part, because currently it doesn't. (It does, however, fit perfectly into the socket.)

- Increase connector and socket height by 0.5mm, to match with original Hornby bogies.

- Increase internal width to accomodate the wheels. Unlike the Hornby parts, these 3D printed ones are too stiff to bend while inserting axle.

- Change height of wheel mount. Currently too low and doesn't stick out like it should.

- Add suspension detail.

 

But for a first try it looks pretty good, and comes with none of the issues that resin casting did.

 

are these bogies still going to come in 2 halves like the Hornby ones to clip together into a full one? or would it be better to have a single bogie for strength and just have some kind of arrangement that its fixed to one end or both coach ends slot onto it?

[RedDwarfIV]

are these bogies still going to come in 2 halves like the Hornby ones to clip together into a full one? or would it be better to have a single bogie for strength and just have some kind of arrangement that its fixed to one end or both coach ends slot onto it?

Two halves. I want my coaches to fit into existing Hornby rakes, and I'd rather not bother with having to print off two different types of bogies, especially when the second type would just make it harder to change the order of the coaches.

 

Besides, I don't think strength will be an issue. Like I said in my last post, these 3D printed bogies are stiffer than the originals. they're far more likely to bend than break, and if you have acetone you can repair them yourself.

[RedDwarfIV]

Full bogie, to show it working with an original Hornby half-bogie.

 

I added a third part to the print. On the originals, the tilt arm is raised half a millimeter above the rest of the top of the bogey, which posed issues for printing it in one piece. So the third piece is a 0.5mm high Y-shaped bit that sits on top of the tilt arm and adds the 1.5mm contact on the end of the arm.

 

Some final adjustments to make:

- Change wheel mount to not stick out quite so far - I overcompensated a bit.

- Change detailing around wheel mount, add suspension detail.

- Add a flat surface to the underside of the tilt arm at the pivot so that the pivot's lower clamp has something to turn on.

[Northmoor]

Tell me about it...

 

You get an eBayer sell it for an overly priced like you say, then all other APT owners think, I'll sell mine now and then proceed to do a buy it now for double the overly priced eBayer APT. Why... I ask myself.

 

Jamie

 

Sold my "spare" yellow-cabbed APT at the weekend in an eBay auction for just under £85 (started at £70).  Hope it went to someone on this forum who will make good use of it.  

 

I have so many projects that I have had to be brutal with myself and realise that making a cut-n-shut APT from two sets is waaayyyy down the list to get done.

 

FWIW my listings always include the statement that "No I don't have a buy-it-now price in mind"; I have seen one or two individuals ask that of multiple listings (usually job lots) when surely if the seller had such a price, they'd have displayed it in the listing.

[RedDwarfIV]

Went to B&Q today because I remembered them having paint matching cards there. I was not disappointed.

 

Earlier in the thread, people were giving suggestions as to what paint colours the APT model uses. I ordered some Humbrol paint in those colours and was quite disappointed. The executive blue was too dark (almost black, in fact) and the Intercity Grey was a very dark grey instead of the light grey I thought it would be.

 

But at B&Q I was able to hold an APT carriage up to cards and match it. I found that the body shell is X144/R283C Dusky Parakeet perfectly, though the closest I could get for the window strakes was L17D/W36B Inky Prose.

 

[Classsix T]

Whatever else, it seems B&Q is the place to go for a random pub rock band name generator!

You'll be telling us their white is called Arctic Monkey next.

 

C6T.

[Wolf27]

Went to B&Q today because I remembered them having paint matching cards there. I was not disappointed.

 

Earlier in the thread, people were giving suggestions as to what paint colours the APT model uses. I ordered some Humbrol paint in those colours and was quite disappointed. The executive blue was too dark (almost black, in fact) and the Intercity Grey was a very dark grey instead of the light grey I thought it would be.

 

But at B&Q I was able to hold an APT carriage up to cards and match it. I found that the body shell is X144/R283C Dusky Parakeet perfectly, though the closest I could get for the window strakes was L17D/W36B Inky Prose.

 

I assume you are colour matching to the incorrect Hornby colours? I had to resort to mixing my own and whatvacfaff it was too!

 

Cheers

 

Shane

[RedDwarfIV]

I assume you are colour matching to the incorrect Hornby colours? I had to resort to mixing my own and whatvacfaff it was too!

 

Cheers

 

Shane

I am indeed. Though I could probably make ones with the correct colours just by using different paints. I don't know if anyone but Wolf27 has correctly coloured APTs though.

[Dagworth]

I am indeed. Though I could probably make ones with the correct colours just by using different paints. I don't know if anyone but Wolf27 has correctly coloured APTs though.

My set is still in Hornby colours, one day I will get around to respraying it

 

Andi

[Kelly]

If you're a DEMU member, a recent update issue had a good article on colour matching to authentic BR colours.

[Flood]

Personally I don't believe that the APT was ever painted in the executive greys. The executive light grey has always managed to show a fawn tinge in certain light which I have never seen on APT photos from 1978 to 1988. The fact that the first APT vehicles were painted 5 years before the first executive HST sets makes me believe that the colours were changed. Executive dark grey also has a slight brown tinge so whilst the Hornby dark grey is too light I also am not convinced that Executive dark grey was used on the APT.

Edited September 16, 2017 by Flood

[RedDwarfIV]

You think you know all the issues your 3D printer might have, then it goes and socks you in the face with a new problem from left field.

 

 

Tried printing nine of the short shell parts at the same time. Printing time: nearly 9 hours.

 

Print failure: 40 minutes from end of print.

 

Cause: Extruder freegear clogged with debris, causing increasingly loud and worrying grinding noise.

 

Fix: Remove freegear, clean freegear and mount, spray mount and gear with GT85 lubricant, return gear to mount.

 

It's no longer making the grinding noise, and I will no longer be doing 8 hour prints unless absolutely necessary.

[RedDwarfIV]

Been doing a bit of spraypainting. Looks like Dusky Parakeet is a bit too light. Can't tell if Inky Prose is right because of how it reacts with the bumps between print lines on the surface of the window strakes. I may be forced to redesign the strakes with that in mind - print the wall and the window frames separately (the side of a part that faces the hotbed is always flat thanks to the ABS cement I use to stick the parts down. That should make a perfect surface for paint.)

 

Would probably also require printing some sort of cover to go over where the frames would be so paint doesn't get in the way of sticking the window frames on after painting.

 

In any case, a surmountable hurdle when I get the motivation to do it. Currently in the process of buying a plot of land as well as repairing the bike I use for work. Bit stressful.

[Pete the Elaner]

 

 

Fix: Remove freegear, clean freegear and mount, spray mount and gear with GT85 lubricant, return gear to mount.

Are you sure this is the best stuff?

I believed it to be an oil-based water dispersant like WD-40, not a lubricant. Heat will burn it off.

A quick search has confirmed this.

A silicone based lubricant should work better.

[RedDwarfIV]

Are you sure this is the best stuff?

I believed it to be an oil-based water dispersant like WD-40, not a lubricant. Heat will burn it off.

A quick search has confirmed this.

A silicone based lubricant should work better.

Huh. I'll look into that, I know Halfords sells some.

 

I knew water displacers didn't work as lubricants, but for some reason I thought GT85 counted as a lubricant.

[RedDwarfIV]

Thanks to Dagworth for providing APT blueprints, without which this wouldn't have been possible.

 

This is the insert for the buffet/restaurant car.

[RedDwarfIV]

Inserts for 1st class and unclassified carriages.

[RedDwarfIV]

Update: I've been having to work out how to paint the window strakes. They require three different colours - white, (unidentified bluish-purple), silver - and they all need to be applied carefully or they'll look sloppy. But doing it carefully means taking ages to do each one, so I've been coming up with ideas for how to do it fast and right.

 

For the silver I used a metallic silver spray paint can. For the bluish purple, I think RAF Blue-Grey (BS381-633) works better than Dusky Parakeet. Neither is the exact right colour, but blue-grey is closer. For white... I'm undetermined whether I should just use the unpainted white ABS surface or actual white paint. I'll decide which looks better when I actually try putting white paint on it.

 

The strakes I printed off with the window frames removed work quite well for constraining the silver paint to the rims if I put the frameless strake on top of the framed one while spraying. But because it was part of a defunct plan to print the strakes and frames separately, the window holes are slightly too large and the result is overspray. I can fix this by just printing off new frameless strakes with the correct window size.

 

The silver can be sprayed on top of the blue-grey paint. So the painting process will probably go like this:

Step 1: Use tape to cover the area that will be white

Step 2: Paint everything else blue-grey

Step 3: Cover strake with frameless stake

Step 4: Spray silver through window holes

Step 5: Remove frameless strake

Step 6: Remove tape

Step 7 (optional): Paint white band across bottom

 

I've yet to work out how to add the red buffet or yellow first class strips. I have paint for this, but it seems quite runny.

[RedDwarfIV]

 

A few things to note. I've extended the strakes by 2mm, so they are now the same length as the carriage. I also moved the window holes so that they line up properly with the roof supports - previosly the windows were not symmetrical for some reason. I also made a slight redesign to the body shell around the edges of the windows to reduce the amount of space between the strakes and the roof. It might not be obvious in these photos, but it makes it look a lot better.

 

As for the paint, you may have noticed some blue smudging... and that the red stripe went everywhere. I'll be working to improve my painting technique to avoid these. Making a cover for the white stripe should fix the blue smudging, while the red stripe should work better if I spray paint it rather than trying to use a brush.

 

I haven't done the silver spray on these strakes yet. Also, the glossy look is mostly due to my camera's flash. I'll probably use matte varnish on it when its done.

Edited November 19, 2017 by RedDwarfIV

[RedDwarfIV]

Attempt 2.

 

 

I may do what I did with the strakes and add a groove to show where the red and grey paints should go. Would keep the red stripe more in the right position.

 

Honestly though, it looks fine from a distance. I'll probably use this one for my own APT.

Edited November 22, 2017 by RedDwarfIV

[RedDwarfIV]

 

Buffet and second class coaches.

 

It may not be obvious, but both of these coaches have clear acrylic sheet for windows. I modified the body design so that the windows can be placed underneath the strakes, and between the roof supports, with no cement required to hold them in place. This should significantly reduce workload and time to build each coach.

 

Please note that the join will be less visible when I actually cement the two halves together. I haven't done that yet because I may want to work on the inserts more and add interior lighting. Also, the old bogeys were added for demonstration purposes, I didn't have the time or the 240v wire to fit 3D printed bogeys right now.

Edited November 24, 2017 by RedDwarfIV

[plasticbasher]

Wow - this thread I started way back when has turned into something so impressive!!   

 

Very impressed by the potential in those 3D ones too.  Much get some phones up of my cut'n'shuts up (still unpainted as I'm scared to ruin my work so far).

 

plasticbasher

[RedDwarfIV]

I'm scared to ruin my work so far

Honestly this was one of the big motivators for me to do this. Cut-and-shut means buying £40 worth of carriage with no guarantee that you won't botch the work when trying to put them together. Buying enough carriages to make a 14 car rake, or even two 14 car rakes would be a massive investment.

 

With a 3D printer, if I break a carriage beyond repair, I just print another one off, no biggie.

 

And I say this having actually botched two attempts and got a sub-par result out of the third.

Edited November 26, 2017 by RedDwarfIV

[Colin_McLeod]

This is a brilluant thread but Murphy's law strikes again.

 

http://www.rmweb.co.uk/community/index.php?/topic/128566-oo-gauge-crowdunded-apt-p-warley-announcement/