Wolf of Badenoch

P A D

Western Thunderer
I just secure a brass wire around or to the motor or gearbox. Locate the other end to a cross frame member. This leaves the motor unit all the movement it requires but stops the rotation.

I shall need to do something like that on my 3P as it will bd driven on the center "sprung" axle.
 

Richard Spoors

Western Thunderer
I've now started on the motion bracket and valve gear. I decided to make up a motion bracket module first. Once this is fitted to the frames the lower level of the bracket sets the horizontal and vertical position of the slide bar and hence the position of the cylinder.
I shall minimise the use of nuts and bolts recommended in the kit instructions. The expansion links have been opened out and pins silver soldered instead of the through bolt. 87373176_2824388664318980_3532638806010232832_n.jpg

I have not fitted the motion bracket covers yet.

Cheers

Richard
 

Richard Spoors

Western Thunderer
A little more progress, this time the loco brake system. Looking at original drawings, Mr Thompson changed the design of the brake linkages on each crossbeam when compared to Gresley's pacifics, so I started with plain Ragstone castings for the crossbeams. However, Ragstone does produce a nice crank that links the steam brake cylinder to the linkages. Because the driving wheels on the Thompson A2's are close together, I soon realised I would be ditching the white metal castings in the kit for some 3D printed brake blocks. Using plain cross beams the linkages were made up to follow the original design. I made up some longer clevises from 2mm square rod with an 0.8mm slitting saw in my mill. The individual links were somewhat fiddly, but I think it was worth the effort.
3D brake blocks.jpg A2-2 Loco Brake System.jpg

Cheers

Richard
 

7mmMick

Western Thunderer
Richard,

The brake gear is a huge improvement and something I’ve been pondering over whilst 60514 sits to one side. I have the ragstone parts in stock and will attempt to follow this method when time permits,

Mick
 

Richard Spoors

Western Thunderer
IMG_2125.JPG
This build has been my usual slow 'a bit at a time' plod, but I'm now pleased to say that readiness for an application of paint is only a few days away. I did prolong the build with a decision to clean off nearly all the cast rivets after viewing photographs taken from above of 60506 after her last general overhaul in 1959 on the Kings Cross turntable. The forward section of frames was scratch built after I realised that the dominant stretcher bolts in the kit etches were wrong. Sadly the designer had not taken the trouble to view photographs and count them!
IMG_2126.JPG
She will be DCC with a Zimo 696KS (without the adapter board) which is 29mm wide, so a brass smokebox door ring was turned on the lathe with two slots to receive the smokebox door and allow the decoder and speaker to pass through after she's painted. Both tender and loco superstructures (plus cylinders, cab roof etc.) will be in the hands of Warren Haywood whilst I tackle the respective frames. The cab interior parts will all be fitted after painting, otherwise I can't get the backhead in!
 

simond

Western Thunderer
The chunky loco mainframes are designed in such a way that the motor has to be fitted to the centre driving wheel. This presents a challenge when opting for sprung hornblocks as the axle carrying the motor must be able to have vertical movement. Whilst my solution may seem over-engineered, it works!
Here is how I went about it. Using a milling machine and a vertical slide I produced a brass block to fit inside the frames and fit to the diameter of the motor. Finding a mini fly cutter was difficult as the cutting radius is 11mm. My Unimat cutter was too big, but I found one at Arc Euro Trade.
View attachment 118821
This was then attached to the motor with cyno glue and test fitted so that there was a vertical face for upwards and downwards movement
View attachment 118822
I then soldered between the frames a section of 4mm square tube, set against the vertical face.

View attachment 118823
I then made two arms that could be screwed into the brass block. These serve a dual purpose to hold the motor in position and to allow it to move vertically.
View attachment 118824 The 'arms' are made from 0.5mm brass strip. The challenge was to make them both the same size and to the correct depth to fit over the square tube in the frames. To cut a folding line in the brass strip I used a centre drill as a milling cutter in the mill, and slowly cut the folding lines 0.05mm at a time. The folds were then reinforced with a touch of solder.
View attachment 118825 The finished work with the motorised axle able to float in the hornblock, seen here at its uppermost position. The chassis and motor also fit the prepared slot in the boiler without additional cutting being necessary.

As I said at the beginning, this might be over-engineered, so it would be interesting to hear how others have managed to fix their motors in position longitudinally with vertical axle movement.

Cheers

Richard

Richard,

You need only to stop the motor rotating about the axle - you want it free to rise and fall at the axle end, and to rock from side to side, all other motions are constrained by the horns. The basic approach requires a link from somewhere on the motor, as far from the axle as possible, to somewhere convenient on the frames. Said link needs to "pull" and "push" and be free to rotate in all directions. Alternatively, a peg on the motor fitting into a hole on the frames (or vice versa of course) will do the same thing.

You can get as sophisticated as you like, with straps around the motor, and rubber grommets in the link, or you can follow Pete's advice and keep it simple with a bit of bent wire or fret waste. I think I did one loco with a rigid bit of NS fret waste bent to be parallel to the motor body, and two o-rings on the motor - one between it and the NS and the other holding the two together. It wasn't tight, but just enough to stay in place. Another "relaxed" approach is a bit of foam in the body, and similar between motor and chassis, just to keep it from rotating.

In reality the axle movements will be tiny.

hth
Simon
 

Richard Spoors

Western Thunderer
Richard,

You need only to stop the motor rotating about the axle - you want it free to rise and fall at the axle end, and to rock from side to side, all other motions are constrained by the horns. The basic approach requires a link from somewhere on the motor, as far from the axle as possible, to somewhere convenient on the frames. Said link needs to "pull" and "push" and be free to rotate in all directions. Alternatively, a peg on the motor fitting into a hole on the frames (or vice versa of course) will do the same thing.

You can get as sophisticated as you like, with straps around the motor, and rubber grommets in the link, or you can follow Pete's advice and keep it simple with a bit of bent wire or fret waste. I think I did one loco with a rigid bit of NS fret waste bent to be parallel to the motor body, and two o-rings on the motor - one between it and the NS and the other holding the two together. It wasn't tight, but just enough to stay in place. Another "relaxed" approach is a bit of foam in the body, and similar between motor and chassis, just to keep it from rotating.

In reality the axle movements will be tiny.

hth
Simon

Simon, thanks for your reply. As the drive is designed to be on the centre axle I have fitted hornblocks to all 3 axles and as well as preventing rotation, I have allowed for some vertical movement to the driven axle. It runs well as an 0-6-0!
Cheers
Richard
 
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