DrDuncan's 3D workbench

[MikeOxon]

You seem to be on a roll with your printing, Duncan.  I'm not sure about U23 having a clerestory though -  http://www.gwrcoaches.org.uk/index.html suggests it was a 4-wheel version of U21.

 

Mike

[drduncan]

7 hours ago, MikeOxon said:

You seem to be on a roll with your printing, Duncan.  I'm not sure about U23 having a clerestory though -  http://www.gwrcoaches.org.uk/index.html suggests it was a 4-wheel version of U21.

 

Mike

You’re quite right it’s a U28 not a U23!

D

[Mikkel]

Very nice Duncan. There's a lovely "crisp" look to the coach, including the door vents.

[drduncan]

The upper footboard supports are rather fragile though. I’ve broken 3 off the test piece already…

[drduncan]

So, in between building mixed gauge track I have continued to work on some 3d prints.  The cleminson chassis used for my BG fish wagons works but needs some adjustment as it seems to be a little too tall making the wagon sit high on the rails.

 

 

I have also chamfered the rear of the brake shoes to allow a little more side play.

 

With track building leaping forward I have also started work on a mixed gauge buffer stop and scotch blocks for protecting the running line from stock running away in the sidings.  

 

For those who are interested in 3d printing or any of the stuff I have been working on, I'll be demonstrating 3D printing and CAD at the SOuth Hants MRC show in Portsmouth, Saturday 19 Nov, 1030 to 1630:

https://www.shmrc.org.uk/exhibition/ 

 

 

Edited October 10, 2022 by drduncan

[drduncan]

I’ve printed off a revised Broad Gauge U20 composite with integral vac cylinder assembly (because I forgot to hide in on the U21 body and it came out fine so I thought why not…) 

 

Ive started adding brass details, v hangers and upper footboards as well as the outer w irons. 
 

 

Hopefully more work on it will be done by the time I demonstrate CAD and resin printing g at the SHMRC show, Admiral Lord Nelson’s School, Portsmouth on 19 November. Do come along and say hello.

 

Duncan

[drduncan]

Dear all,

 

I'll be demonstrating 3D printing and CAD at the South Hants MRC show in Portsmouth this Saturday.  Hopefully - resin and 3d printing gods permitting - I'll have samples of the BG U20, U21 and BG N6 loco coal wagon as well as the SG U21, U28 and N6 for people to look at.  

 

Do come by and say hello if you are coming to the show.  The show is open on Saturday 19 November at Admiral Lord Nelson's School, Portsmouth, 1030 to 1630. See https://www.shmrc.org.uk/exhibition/ for details.

 

Regards,

 

Duncan

Edited November 14, 2022 by drduncan

[drduncan]

It was a very busy day and an excellent show - well done SHMRC.

 

Many thanks to everyone who stopped by to say hello, ask questions or pass comment on the 3D prints I had on display. I didn’t really stop talking until mid afternoon!

 

Duncan

[drduncan]

So while trying to sort out distortion at the point  closest to the build plate - see @garethashenden thread on the subject - I’ve been working on my broad gauge 3521 saddle tank. 
 

I have printed the chassis and I have started a test build to see what is or isn’t working.

 

The fitting if brass top hat bearing for the fixed driven axle worked ok and today I made up full width bearing for the rocking trailing axle and fitted it.

 

 

The plan is that the motor will sit vertically in the firebox. The footplate has been printed with the lower part of the boiler included so that this can be used to hold the DCC chip. 

This printed well enough to test fit, but it printed poorly at the rear of the lower boiler and the front sand boxes so some revision is needed.

 

I need to fit the horn blocks to the front driving axle but to do this I’ll have to negotiate the Alan Gibson ordering system to get the 7’6” coupling rods that are needed. I do have two sets of Lancashire Model Supplies variable length rods for planned models of GWR 13 and 34 both in original condition - ordering them was a doddle, just a couple of mouse clicks and done, but unfortunately they don’t do 7’6” rods for a 4 coupled loco.

 

All the best,

 

Duncan

[garethashenden]

http://www.lanarkshiremodels.com/lanarkshiremodelsandsupplieswebsite_058.htm

🤨

[drduncan]

My mistake, I need 7’ ones

[drduncan]

More progress on the Broad Gauge 3521saddle tank. 
 

I’ve now fitted the motor and gearbox - a high level box and a Mashima 1220. I also soldered the rocking trailing axle bushes to the pivot bar.

I have also been given thought to pick ups.

Naturally I thought about this after I printed out the chassis, but that is what files and dental burrs are for! It struck me that the top of the gap between the inner and outer frames might be worth a shot, so I filed and ground a slot to take a bus bar on each side on to which phosphor bronze wire scraper pick up will be soldered.

After trying some 0.8mm brass rod for the bus bars, I decided on .5mm.

 

I’ll be able to incorporate the groves for the bus bars and pickups on the CAD for the BG 3521 0-4-4t which is coming in behind the saddle tank version in the CAD queue.

 

Next job is to increase the width of the footplate by 0.25mm each side and move the balance out by the same amount as the clearance in the rocking (from) coupled axle is non existent! And then reprint with better supports to hopefully  cure the poor printing of the front sandboxes and rear of the lower boiler.

 

[drduncan]

Today’s progress on the BG 3521 st…

 

The bus bars were glued in place and then wipers from thin PB wire soldered in place.

 

 

Then an 8 pin dcc socket connected up.

 

 

Next job will be fit and quarter the wheels and then fit coupling rods. And test - and hope everything works as it should!

 

Duncan

[stevel]

 

have you seen this way for holding pickups, might be easier for your reprint.

pic from Dib's yard on Instagram.

[drduncan]

No I hadn't seen it - an interesting approach. Thanks.

 

D

[drduncan]

So the 3521st hasn’t quite stalled. As I type the mark 2 chassis and mark 2 footplate (0.5mm wider between the inside faces of the valance) are printing. Fingers crossed.
 

I’ve also been working on the CAD chassis for the BG/SG 0-4-4t versions. Here the stumbling block is the bogie. I want pick ups on at least one of the bogie axles, preferably two; so how to get the volts from the bogie onto the chassis proper? Ideas please.

 

Also the bogie will need to be compensated (as there is fag paper thickness clearance between the top if the damn thing and the frames do making it flop about won’t work. So that means some sort of drop out sub frame, or removable outer frames (so that you get the wheels and axles in place). Question are how to arrange these matters so that it is easy to fit together and can be taken apart with minimum fuss to get at the wheelsets? Again suggestions, isometric drawings or photos of how you’ve done it/would do it will be very welcome.

 

Duncan 

[drduncan]

The Mark 2 valence printing failed; the steps which were fine in the MK1 just aren’t thick enough. Or possibly it was washed for too long. Anyway trying again to be sure. 
 

However, the failed print was good enough to do a fit check and all seems good so far…

 

The mark 2 chassis came out well and I just need to decide whether to strip the mk1 or have 2 saddle tank versions. I’d best count the number of wheels in the stash….

 

You can see all the cut outs for the busbars and pickups very clearly.

 

So a quick count shows I’ve enough for 2 BG 3521s and two NG ones without ordering more just yet. So I think it may well be a strip down of the mj1 chassis as I want the 0-4-2st and 0-4-4t versions in BG for Nampara.

 

Duncan

Edited June 3, 2023 by drduncan

[garethashenden]

I like to put a couple of loops in the pickups as shown here. It gives a bit of flex that allows the pickup to be sprung against the wheel without acting as a brake. I also think I'm using thinner wire than you are. This is 0.010" phosphor bronze. Just something to think about.

[drduncan]

So I’ve been working on the Mk2 3521st Briad Gauge chassis. Having cleaned up the print, today I added the spring hangers from 0.5mm brass wire.

 

 

I also added the bus bars (but got ahead of myself - forgetting the master plan I’d decided on…

 

Tomorrow (or a yet to be determined day) the plan is to clean the print of dust, then undercoat it in red oxide (Halfords best rattle can paint).

 

Then I’ll airbrush it Indian red and do all the wheels at the same time. 
 

While all this painting is drying I can strip the mk1 chassis of horn blocks etc and get ready to fit them once the paint is dry.

 

Then it will be reassemble the wheels, pick ups  and motor; hey presto an almost finished chassis!

 

Duncan

[drduncan]

I will be demonstrating 3D printing at the Great Western Study Group open and members day at Didcot civic hall, Saturday 15 July, 1030 to about 1430.

 

Do come along and say hello!

 

In other news the 3521st chassis was sprayed red oxide yesterday while fending off all my children, all of whom felt their life chances were devastated by my refusal to let them…

 

Duncan

[Schooner]

To let them what?! Concerned for own life chances now...!

[drduncan]

Spray the 3521 chassis red oxide!

[MikeOxon]

9 hours ago, drduncan said:

Spray the 3521 chassis red oxide!

I'm sure your workroom would have looked very nice in overall red oxide colour 😀

[drduncan]

The GWSG members day and open day is this Saturday! It’s free to non members too…

 

I’ll be doing CAD and 3D printing there so do come by and say hello 

[drduncan]

So, as a partial excuse for not posting for a while, I have been playing with a new printer - an Anycubic MonoX2. 
 

Some interesting findings:

1.  It can accommodate 9 x 16ft (ish) long wagon bodies, if you print them at 45 degrees. 
2. it is faster than my old photon mono.

3. Not only will it print 48ft coaches in a single print, but much to my surprise, it will do a 57ft coach at a 45 degree angle. It might even do 58ft one - if so lots of CADing GWR clerestories lies in my future.

 

Duncan