Princess Coronation City of Stoke on Trent (slow burner project)

Firstly this build will be a slow burner project so please don't expect anything to start just yet... I've the Rebuilt Patriot to complete (awaiting small nuts and screws for the removable motion) and of course a return to Leek Passenger station buildings diorama.

Anyway I went and picked up the kit from one of the consortium (Mick says hello Rob) and yesterday the loco build instruction and diagram manual arrived so I've now been having a serious look at the build process and reading Richard Lamert's thread from 2015 (another forum site and a link to it from the Finney 7 LMS Princess Coronation kit page) for those who would like to read all about it. Now I see where Richard is coming from regarding his certain concerns over chassis springing and compensation with the original Martin Finney design which arose out of the test build.Bare with me please folks and you'll see where I'm coming from in a minute.

Now this kit includes working inside motion so the forward driving wheel must be removable with the horn blocks from their guides due to the interior cranks, the kit makes the original front axle compensation springing apply too much force onto the centre of this axle at its most weakest point... so I'm with Richard on this one by doing away with this wire / tube centre sprung design and replacing with a 12BA screw with coil spring set as an axle stop from the top top face of the horn guide kit. Finney 7 provide their own design of hornblock which the builder assembles as a lamination. So the centre and rear driving axle are designed to be fitted with a compensation beam ( if the loco is intended to be sprung) the problem here is the beam is incredibly narrow around the area where the brass axle bearings are soldered in and again agreeing with Richard this is another area of weakness and potential failure. I'm inclined to leave the rear driving wheel axle (which will carry the motor gearbox combo) as a fixed unit and make the centre driving wheel axle a sprung hornblock with upwards and downwards movement. Of course the hornblock bearings will have to be stopped from simply falling out of their guides so I'm thinking if I make the etch assemblies of the loco springs removable from their support brackets (these brackets form part of the sideframe etches) then that will hold the sprung hornblock bearings in position.

I'll add some photos of what I mean over the next few days but in the mean time I wondered what other members opinions were regarding a fixed rear axle arrangement and both way springing on the centre axle along with downward only springing on the front axle. All comments gratefully received... this is a big loco build and one I shall take my time over and don't want to make costly mistakes.

Thanks again.

Yorkie

 

Thank you for the sound advice... I am much appreciated of it. My concern in using 12BA hex screws to hold the hornblocks in place via the etch chassis spring pieces was clearance to the wheel flanges, however I'll do some dry building to what clearance are to be had prior to drilling and taping out the holes which will be done prior to any soldering assembly of the chassis frames. Interestingly the chassis spacers (I'm going with the O Finescale set and not the Scale 7 ones) are 1.5 mm (approx) wider than the chassis spacers on the Rebuilt Patriot currently on the bench... so much so that I have had to fit packing washers onto all wheelsets on the Patriot to avoid "hunting" and undue stress on the rods. I'll put some pics up in daylight tomorrow so folk can get a visual on this topic.

Anyway on another note the Finney team are currently working on a B1 kit to be released in late Spring 2023, Richard has added me to the list with one reserved for me. Yes B1 locos did come to Leek around the early 1960 period heading day out excursion trains to Alton Towers... often these locos laid over in the yard because of the nearby watering facility there... so Leek diorama will have a B1 and I can confirm as a child I did see them light engine at Leek but no idea what the numbers were or where the excursions originated from.

 

Its fits and starts with me too Paul... I'm not able to spend hours at a time soldering stuff... I still have the backhead and glazing to do on my 4F

 

Yes 'fraid so and I did also cut the spectacle glazing shapes prior to building up the cab... maybe Toto has a donor 4F loco you could use as a template for this job, sorry Toto lets look forward to the time when three 4F locos can all run together on a layout.