Monthly Archives: February 2023

David Andrews Princess Royal – Fitting the Inside motions and modifying the rear hornblock to acoomodate the taper pin.

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I seem to have been really busy with real life and not a huge amount to show for the work on the Princess.
I have returned to the chassis while I await castings for the back head and the firebox print – Royal Fail seem to be keeping their reputation intact FB posted a week last Saturday and replacement castings from Ragstone posted a week yesterday, no sign of either yet.

On the rear axle which is to be driven there isn’t a great deal of room on the axle for the gearbox, hornblocks and taper pin. It turned out that after trying everything the taper pin actually sat under the left hand hornblock. Initially I tried cutting down the taper pin so that it just went through the axle and would spin inside the horn block. I obviously didn’t make it a tight enough fit as it went walk about. Thankfully I do have a few spare taper pin so I was able to replace it but I didn’t want the same thing to happen again so after some thought I hit upon the idea to thin down that hornblock. I took it out and milled 1mm off the rear of it. Which you should be able to see from comparing the first two photos

David Andrews Princess Royal – Rear bearing and taper pin fitting
David Andrews Princess Royal Centre Bearings

Next I moved onto fitting the representation of the inside motion. I had to solder the eccentric straps together and then make some location points for the slide bars and lotion plate.

David Andrews Princess Royal – Inside motion fitting

I have done this with a couple of strips of scrap etch and the plan is to mill a couple of small angle plates to allow the cylinder front to be screwed in place. I will take some more detailed phots once I have finished this.

David Andrews Princess Royal – Inside Crosshead.

Subject to retaining it I have achieved what I set out to, you can see the cross heads through the openings in the frames, with a small amount of visible movement when the axle is rotated.

GNR Tender Tank Vents

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In between the multiple redraws of the Princess Firebox I maintained my sanity by doing a little more lathe work.

In the to do pile I have three GNR Tenders and having had a peek in the boxes all the castings are whitemetal. To be fair Two of the Tenders are Gladiator and the castings are nice castings the third tender is an ACE Products tender and the castings are not quite so fine. In any event I much prefer turned ones as they look much more crisp in my eyes. That and I enjoy making them.

GNR Tender Tank Vent

This was my first attempt but I got the angle of the top wrong so I had another go.

GNR Tender Tank Vents
GNR Tender Tank Vents

I did manage to salvage one of the first attempt and re-turn it to the correct 45 degree angle The second one I managed to gouge with the tool bit so that awaits being sued for something in my potentially useful bits box.

The two without rims are for self trimming tenders where they have a slightly curved rim which fit over the top edge of the coal space. Having checked my tenders I need to make another pair without rims as two of my tenders are the same self trimming type. Albeit one is from Gladiator and the other ACE

David Andrews Princess Royal – Final, final redraw of the firebox

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Although Happy with the final result drawing wise, I still wanted to improve the print quality by make it as good as I can. I consulted a couple of very knowledgeable people whose principle advice was that I had the walls of the print too thick. The recommendation being around 2mm (it was 7mm at this point). I did manage to reduce it to 5mm without breaking anything that couldn’t quickly be fixed, but to get it to 2mm required another redraw. Thankfully I was able to reuse all the detail parts such as boiler bands and mud hole covers that I had drawn previously by using the derive function.

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It’s now gone for print so fingers crossed this should be the final iteration.

Stanier Tender Tank Vents – Replacements for castings

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Needing a break after redrawing the firebox for the Princess I decided to do a bit of machining for therapy.
I noted on the two recent Stanier tender builds that despite having brass castings for the vent pipes, none of the castings were that great and needed work to make them usable. The late David Smith (DLOS as he was known) always turned replacements and I decided to have a go myself.

Before starting I decided to have a look in my Finney Duchess kit to see what the casings were like.
I don’t know why but I was slightly surprised that the vent castings were whitemetal.
Now it’s worth noting my kit came from Martin Finney himself some time before the Finney 7 Team took over, so they may have upgraded the castings in the meantime. On the basis that I am not that wild about whitemetal castings I thought that making replacements for the Finney tender would be a good place to start.

I imported a snip of a GA into Fusion and used that to create myself a sketch which I then generated into a working drawing using the the drawings function in Fusion

One thing to note is that the drawing classes itself as one of your allowed 10 editable designs.

Finney Vent Casting
Home Turned Stanier Tender Vents
Finney Stanier Tank Vents alongside home turned examples

I also have a Rebuilt Scot in the pile so I did a second pair for that while I was on with it.

Don’t get your hopes up for this build to start anytime soon though, sorry.

David Andrews Princess Royal – Firebox Saga

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It’s all been a little quiet on the Princess front. I got the second test print back and to my dismay there was a large* gap between the  front ring and the front of the firebox

*I say large it wasn’t that big in reality but certainly too big too disguise.

I returned to the drawing board and then discovered that I had misread the drawing so I drew it again. After my redraw there was still a 0.3mm gap at either side so I took a copy of that design and hacked it to correct it. 

Although I managed it I wasn’t happy with the way I had gone about it so I took a second copy and tried to adjust the sketches but because I had made the fundamental error of adding all the details before the adding front ring which fits inside the kit boiler and checking the interface between that and the firebox front. The net result of altering the sketches to make them wider created so many errors that in the end I gave up trying to correct them and started again.

This time I drew the basics and made sure that the overall dimensions were correct and worked together before I added the details. It’s now on it’s way for what I hop will be the final print.

The good news is that I didn’t need to redraw the lower sections of the firebox because I checked that they still fit as I was going along.

David Andrews Princess Royal Replacement Firebox Version 5