Dave Bradwell 14t Steel Hopper (Charles Roberts) 4mm P4

​This has been loitering with intent around the workbench for a few months. It's for my eventual, maybe, sometime colliery layout. I'm building up a collection of NCB internal user wagons. A real mixed bag of knock about, retired stock. Industrial wagons aren't that common as models so I was very pleased to come across this from Dave Bradwell. I'll probably build a couple more, but this one was to see how it builds. I've been getting some time in between episodes of the 7mm MMP 1/08 build.
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20 March

The etch is a single sheet, neatly laid out and of good quality. There are several A4 sides of printed instructions and a fair number of sketched diagrams. The diagrams are hand drawn, not the CAD output we're becoming used to, but clear enough. The kit provides the etch and a length of phosphor bronze wire for the springs. You have to find the other bits and bobs yourself. There's a list of the items you'll need to source, nothing too difficult to find.

Under frame part 1. The easiest way to remove the Alex Jackson brackets is to score heavily where you want to cut them off, then bend back and forth gently with pliers. They'll fatigue off neatly.

Solebars part 2. The way the W irons, steps and solebar flange are incorporated in one part is clever, maintains accuracy and saves the hassle of adding them as separate parts later. But study the diagram and work out how it folds. Some fold lines are on the outside of the bend; W irons and first step bend. Note also that the tread plate on the steps was slightly curved to prevent feet slipping off the edges. Bend the steps gently without breaking the half etch tab, it'll be a right faff to reattach the steps if you do. Don't be in a hurry to file off the remains of the reverse bend holding the steps to the solebar. Keep it on until the overlays are fitted and the solebar assembly is soldered to the chassis. File it off when there's no more risk of the joint becoming unsoldered.

The red brown thing the chassis is sitting on is half of an old quarry tile. It's a heat proof, clean and relatively flat surface that doesn't conduct heat away from the work and doesn't char or leave crud on the parts being soldered. So far seems to be proof against all kinds of flux.

2 hours.
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Monday 21st March

Solebar overlays. Solder paint or tin the solebar and sweat the overlays to the solebar. Opening out the three slots in the overlay is more difficult than you'd think. DB suggests a piercing saw, but you need a really fine blade, and even then it's a bit snaggy on the overlay. Could have been etched in the overlay: forgotten on the artwork or weakens the overlay too much? Clean up the solebars and that's all I have time for tonight.

1 hour. Total 3 hours.
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Tuesday 22nd March

Cross members 8, 9, brackets 10, 11 and solebars all clip neatly together and hold each other in place for soldering. That's clever design. I started the soldering together in the middle at the V irons, the brackets 10, 11 and worked outwards from there. You don't need to solder everything to everything else. A few carefully chosen solder joints should do it. And there's the basic chassis.

1 hour. Total 4 hours.
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Wednesday 23rd March

Fold over and solder brake tabs on 8, 9. Some tidying up. Cut out and bend diagonals 12.

0.5 hours. Total 4.5 hours.
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Thursday 24th March

Diagonals solder into place easily. Platforms 16, 17, tin the back lightly before cutting from the fret. Sweat or RSU into place.

Time for a trip to the ultrasonic bath.

1 hour. Total 5.5 hours.
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Friday 25th March

Wheels are Ultrascale P4 measuring 25.9mm over axle points. I ought to add that I rate Ultrascale wheels as better than any others by a long way. Never had a set that was less than perfect. Here we go - bearing faff. The first set of bearings soldered into the bearing carriers are much too shallow. The W irons are pushed too far apart by the axle. Same with the second set. The third set appear to have a deeper cone and they do fit. I have a collection of pinpoint wheel bearings from various sources over the years. They all seem to have different cone depths. The differences are subtle and not so easy to see by eye. Any more like the last two? Luckily yes, and finally we have four viable wheel bearings soldered in. Before adding the spring wire it is worth filing the excess length off the end of the bearings. Shorter bearings means less material to scoop out of the back of the cast axle boxes later.

The tabs on the bearing carrier are not long enough to fold right over the spring wire, but bend them up 90 degrees and they help to locate the wire for soldering. Phosphor bronze wire solders far more easily than the steel wires sometimes supplied for this purpose.

The little handrails for the end platforms bent up using the Bill Bedford handrail tool, spaced off the platform with a scrap of plywood sleeper and soldered from beneath. Hint - you might want to leave these off until the rest of the chassis work is done. With the handrails fitted you can't have the chassis flat on its back any more, it rocks on the handrails.

Brake laminations. I drilled 0.8mm and 0.5mm to match the wire I have. Don't solder in the 0.8mm wire yet, just use it for location.

3 hours. Total 8.5 hours.
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Saturday 26th March

Brakes again. Complete the lamination and add all the wire pins. Also added the safety loop from fine copper wire. I think the copper wire came from some old mains flex ages ago. There always seems to be a short length amongst the workbench clutter when you need it. Chamfer off the back of the brake blocks to improve wheel clearance.

Handy hint for drilling small holes or clearing through small holes. I have a set of small drills with 2.35mm diameter shanks. Photo. They go down in size to 0.5mm. It is often easier to use them by holding the shank between finger and thumb and twiddling away than it is to put a similar sized parallel drill in a pin vice. There's plenty of grip for most drilling in the smaller sizes and you have more feel and control, so break fewer drills.

I'm choosing to put on the outside V hangers now. The easiest way to make sure they all line up is to thread a length of wire through all of them across the chassis. Don't solder them to the wire, there's no cross shaft on this wagon.

Quite lot of fiddling and tweaking to get the brakes in place and lined up nicely with the wheels. A few touches of solder and the brakes are fixed. It was far easier to assemble the brakes as a unit and fit them to the chassis than it is to assemble the brakes in situ between the wheels, as some kits have it.

Buffer beam detail on by RSU. Align the buffer pads 5 and hold them in place with a cocktail stick through the hole in the buffer beam while you solder. Time for a break and a clean up.

Safety loops, bit of a pain. Spring stops from strip 26, doesn't really work. Difficult to get them consistent and with crisp bends. A bit too big as well. Had more luck bending a U over the end of a 6 inch steel rule 0.5mm thick, tapping the U onto the ruler gently with a brass hammer to square the U, then bending up the feet with a small pair of flat nosed pliers, and trimming to length with snips. Not perfect, but much better. Soldered to the chassis by RSU and solder paint.

Brake lever guards. More fiddly, faffy bits.

8 hours. Total 16.5 hours.
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Sunday 27th March

Add the stays to the brake lever guards. Always a trial trying to hold them in place and get one end soldered. These days I stick them in place with blobs of solder paint, they're light enough for the solder paint to grab them. Then trap the end of the stay against the W iron with the RSU probe and, without moving it, zap that end in position. Then tweak then other end to touch the brake lever guard and solder it with an iron.

​That's most of the chassis done

0.5 hours. Total 17 hours.