Monday, December 29, 2008

What Body Frame?

click on any photo to enlarge

It's over a year now since the last blog post for which I apologise.
Life is full of distractions such as Craig's need to earn a living as a train driver and pay his mortgage, and my deeper involvement in the running of Sydney Bus Museum at Tempe NSW.
And my old computer now around for at least 8 years has just been pensioned off. It had reached the point where Google didn't support Mac OS9. So no photos could be uploaded, except on my wife's computer, which wasn't always convenient.... Now I have a lovely new iMac with OS10 Leopard and the fun can begin again.
Craig meanwhile however has managed to keep the ball rolling, with occasional assistance from yrs trly. In August 2007 we spent an entire weekend to achieve the complete destruction of the remaining parts of the bottom deck. All was cut up, dragged outside Craig's garage and kept for use as patterns. All very easy and quick; you feel you've achieved something but it's the exact opposite. It's only clearing the way for the hard yards ahead.
With most of the frame components of a new bottom deck already made it was time to clear away the rusty bits of the old. Looking at the photos it seems tempting to keep the many pieces which appear quite OK: trouble is they may have some rust in just one corner which fatally weakens them, and is very slow and difficult to patch and fix. An example is this below: the rear bulkhead of the downstairs saloon which is a major part, holding up the top deck and providing massive diagonal bracing against side to side sway.

The rear bulkhead cut away at floor level and from the side frames. A lot of it is fine, but look closely at the top RH corner and the bottoms of the verticals. Very hard to fix in situ. The extent of the diagonal bracing can be seen.

In between work and living a life, Craig had already removed all the exterior and interior panels, and the flooring of the rear platform. The staircase had gone and all that remained there was the light steel frame of the staircase enclosure.

Craig and I are standing in the doorway to the back platform now cut away from its attachment to the chassis. My hand is on the pillar where I would grab the handrail to jump aboard. A solitary remnant of top deck floor sits behind Craig's head.

Outside the garage, still being help upright by Craig out of shot at right, the frame of the light structure enclosing the staircase, which attaches at left to the rear bulkhead. At right is the aperture for the fixed rear window.

The view from behind of the place where the bulkhead used to sit, on the equally massive rear body cross member. This bit was made by Waddingtons Ltd: the rear chassis cross member, made by Albion, is tubular and just out of sight behind the square section beam.

click on photo to enlarge

The dire condition of the back of the bottom deck. Taken from almost the same spot as above, but further back, a view from floor level of the right hand side of the rear platform, which sits under the staircase. The heavier section at bottom right is one of the two cantilevered chassis extensions which support the platform and stairs. The wood packing is there to raise the offside floor of the platform to create a fall to the left, so that water drains off the platform, not in.

The same area from the offside. The condition of the skirt rail, made of 1 1/4 inch angle iron, is terrible: The burned spot at bottom RHS is where one of the rear bulkhead pillars has been cut away. The heavy section at right forms the step up into the lower saloon and marks the end of the vehicle's chassis. The rear platform and stairs are simply hung off the end, supported on the two extensions underneath.

The tragic remains of the back platform floor. Fortunately not hard to make new, using angle iron and cutting and shutting to get the curves.

Close up, viewed from ahead of the cross beam, the detail of how the U-section end of the back platform extension attaches to the main chassis. The cross beam sits on the chassis ends, and the angled gusset with the hand-sized hole in it is what attaches the beam. At no point is any part of the body welded onto the Albion chassis, because the heat would damage the tempered steel. And supposedly the body could be removed for replacement or overhaul, although this rarely happened.

The main rear cross bearer of the body. It has to support a major part of the entire weight of the top deck and passengers: the rest is taken by the bulkhead behind the driver. and the pillars along the sides, between each window. It is one of the very first items to be fitted by the body builder, by sitting it on the stub ends of the chassis rails. The (Albion) chassis cross tube is visible at top right. The angle gusset with the hole in it (far right) is still attached to the chassis ready to receive the new beam.

The same beam, showing detail of its design; and also, poking off the top, some of the sub frame which supports the floor inside the bottom deck. Although at first glance it doesn't seem to need more than a sand blast and paint job, its outer extremities are rotten and very hard to unpick from the pillars they support. And it is such a vital part of the structure.

Looking pleased with themselves but deep down knowing the real work is yet to come, the destroyers carry out the cross beam. It can be seen to taper from right to left, to provide the
fall on the rear platform floor. It looks complex but is mainly a heavy box section at top, available off the shelf from steel suppliers, and many pieces of 1" and 2" angle.

The process of removing the remaining floor boards begins. Craig has already long ago removed the frame sections from the offside. (See: "Decision: the Bottom Deck Gets New Frame"). The floor has to come up to allow removal of the floor cross supports, so that the bare chassi can go for sand blasting and painting.

The tedious business of chiselling out malthoid and bitumen paint from the screw heads holding the floor down: two screws in every board into every cross beam (at 18" intervals).

Hard to get out an even harder to put back in: the very complex structure around the rear wheel arch. It has a wooden box with a raised floor on which sits a valance (left) and a steel subframe for the longways back seat.

The box over the rear wheel arch is gone, leaving most of the nearside frame standing free after cutting the pillars off at floor level. Rather than try to cut everything into a mass of small pieces , Craig's brainwave was to look ahead and keep whole assemblies as far as possible, so that important small details in construction can be reproduced in the new frame. Note the blue rope at top centre holding the lot up.

Almost the entire nearside wall has been cut off at floor level: sounds easy but we discovered just how much it weighs: a lot. And glass is very heavy. The frame was held propped up as we cut, so that it didn't twist and collapse inwards.
Now, how to get it off the bus and onto the floor. Answer: three men including Craig's father Bill Parkinson. (Who took ALL the photos by the way).

ALL the floorboards are lifted, and almost the only piece left except for the floor cross bearers (which are the bus equivalent of floor joists), is the front bulkhead. It is really very sound and I would have said keep it. But we saw this rust at floor level, and Craig decided it had to go. As can be seen it is sheet steel and some box sections, with some tricky bits where it curves over the flywheel housing and clutch.
Later when preparing to remove the floor bearers, Craig noticed that although mostly free of rust, they were all "banana shaped" i.e. curved downwards, apparently from being overloaded. As they have to come off anyway to bare the chassis fully, they too will be replaced with box sections. Quite simple really.


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