Richard's Workbench - Adams' Radial Tank

Dikitriki

Flying Squad
Hi,

More progress. I have built the frames. Just a case of soldering the spacers one by one (starting in the centre and working outwards), and checking after each spacer that the top of the frames remained flat, the frames were straight, and that the hornblocks were still smooth.

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The locomotive is compensated with twin beams on the drivers, and uses the bogie pivot as the third leg.

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The loco springs hold the hornblocks in place. The rear one is fixed, but the front needs to be dropped for the inside valve gear, so it is screwed in place with countersunk 14BA screws. the srew head is totally hidden behind the wheel flange.

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And I started to add the brass mainframe overlays. If you have soldered the front and rear spacers to the chassis, as I had, you can't fit the overlay in one piece. I didn't want to remove the front spacer - the only option - so I cut the overlay such that the join would be behind the cylinders.

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Richard
 

Dikitriki

Flying Squad
Hi,

The chassis overlays have gone on, as have the brake hanger wires which locate them, and the ash pan. You can see that the rear of the chassis is kinked in to accommodate the radial axle, and I used a skrawker on the rear to mark fold lines to keep it nice and sharp to follow the line of the chassis sideframes.

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That's the humdrum but vital part of the chassis done - now for the interesting details.

Richard
 

Dikitriki

Flying Squad
I've done the hard work on the cylinders.....

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Splendid nut detail on the front and back of the cylinders. It did take a fair bit of filing to get the crossheads to slide nicely.

To me, they are a bit unusual in that they are inserted into the mainframes from the bottom rather than the top. I made provision for screwing them in place by drilling holes through the bottom supports, both on the chassis and cylinder, and tapping the cylinder bottom 8 BA. When the excess thread is cut off flush with the bottom of the cylinders, there is nothing visible or which can interfere with the free travel of the bogie.

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Richard
 
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Dikitriki

Flying Squad
Hi,

I've now completed the cylinder unit. The only tricky bit is soldering the steps on without disturbing the slidebar/bracket bond. I used a higher temperature solder for the slidebar/bracket join, soldered the treads to the step backing with higher temperature solder, then used 145 degrees to solder the completed steps to the bracket. There's lots of verticals and horizontals to get right.

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I can now set up the bogie compensation aspect which is determined against the bottom of the cylinder unit.

Richard
 

Dikitriki

Flying Squad
Hi,

I got the compensation set up - 4 etched washers on the bogie pivot, and I now need to build myself a little test curve at 5ft radius to check it will go round - though I don't think there will be a problem. I've built the radial truck, but I will go my own way with springing and retaining it - more next time.

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Always a satisfying moment when it is first on its wheels.

Richard
 

Dikitriki

Flying Squad
Hi

A bit more.

I've finished laminating, filing and polishing the coupling and connecting rods and adding the corks and bolt ends from brass rod.

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I then turned my attention to the radial truck. I had been told that the springing Martin had designed in could be bettered. I wanted to spring the truck, make it removable and limit the sideplay. My solution was as follows:

The radial truck was built according to the instructions, except that I removed that part relating to the original springing.

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The wire pins limit the sideplay so that the back of the flange does not rub against the frame.

I added an aditional spacer behind the rear driver from one of the S7 spares and soldered two 0.7mm phosphor bronze wire lengths to act as the springs

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They bear on the top of the radial truck which has a smooth face.

The truck is retained with some brass strip formed to shape and screwed into the spacer.

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And all together:

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A working, simple radial truck.

Richard
 
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Dikitriki

Flying Squad
The cylinders and slide bar assembly....

If I saw this workmanship in 5" gauge I should admire it greatly. To see it in 7mm is extraordinary!

Thank you Giles. While I appreciate the compliment, I think my life was made easier by the exquisite castings provided in the kit.

Richard
 

Dikitriki

Flying Squad
Hi,

Back from a little break, I took my portable workbench (= my actual workbench, just a different table :) ) and started work on the Radial's footplate.

Quite a satisfying few days' spare time work saw the basic footplate completed. The only tricky thing was forming the footplate itself with those lovely curves. It was just a case of checking often working from side to side and front to back. The valance is attached to a cradle which gives a stable frame to work on, and since the footplate is flush with the front, there is a good reference point as to where the curves must be. It does pay not to rush this and get a good a match for the curves as possible.

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I was not looking forward to making the slide bar inspection covers from 3 etches (base, formed side and top), but in fact they were a doddle, and much cleaner than a casting would have been.

I could have built more of the body on the cradle, but prefer to work with the footplate on the chassis so separated footplate and cradle at this stage. I needed to remove a little from the rear of the mainframes to get the chassis to sit between the buffer beams, and in the picture the footplate is just resting on the chassis as I have not worked out how I want to attach it yet, bearing in mind I will be fitting R/C gear.

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Richard
 

Dikitriki

Flying Squad
Fitting the coupling and connecting rods.

A little more work than is usual is needed here, because the coupling rods run outside the connecting rods.

First the connecting rods. The big end is a proper big end, and is too wide for the Slater's top hat bearing. I used 2 telescopic tubes to make a bearing such that the outer diameter matches the Slater's bearing and the inner hole clears the 12BA crank pin bolt. This is the left hand pair in the photo. The wheel will be on the left of the crank pin, so it goes washer, bearing as above, cut down Slater's bearing, washer and nut. When the model has been tested, the final washer and nut will be replaced with a CPL or LG example.

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For the trailing driver, there needs to be a third section of telescopic brass added on the outside such that the bearing acts as a spacer to keep the coupling rod in line with that on the front axle. This is the right had pair in the top photo. Here it is not necessary to have a washer against the wheel face.

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I am pleased to report the loco ran smoothly without any adjustment to the coupling rods or crosshead travel.

Richard
 

Steph Dale

Western Thunderer
I must admit that the padlocks are one of the details I was looking forward to adding to my BR-era model, only to find they'd fallen out of use somewhat earlier :(

Looking good so far though, Richard, I look forward to getting on with mine.

Steph
 

Neill

Active Member
Amazingly clean workmanship. I've not built this kit, but have completed the Finney T3 which has a lot in common it would appear. The cylinder/motion bracket/step assembly was tricky and is fragile, at least it is on mine! Looking forward to more updates.
 

Dikitriki

Flying Squad
Hi,

I've done most of the rear bunker and cab assembly. All tab and slot, and the fit was uncanny. The bunker top inside the cab I did not solder in at all as it was trapped in place.

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Providing you get the bends on the coal rails in the right place, it just clips in place. It's worthwhile getting all the cusp (not that there is much) off the coal rails and making sure the uprights are absolutely square.

And then on to the smokebox and boiler. The smokebox overlay is marginally wider than the frame, so it makes smoothing off the front and back faces easy.

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Boiler and firebox and front spectacle plate later....

Richard
 
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