The front face of the turret is a seperate section bolted to a machined recess in the turret casting. This piece carries the gun elevation pivots, upon which the gun mount swivels. The mantlet is bolted to the front of this mount, and carries the barrel in its recoil bush. These parts will be the next to be produced over the coming days.
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Continue ReadingIn a perfect world we would want to machine this turret on a large 5-axis machining centre. This would allow access to all the different faces of the casting that require machined details. We do not, however, have such a machine. Instead, the turret has to be produced in a number of manually loaded seperate operations. In the photograph the underside has been machined and the top surface is in progress. These ops are followed by smaller operations on the front and the angled sides and rear.
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Continue ReadingThe centurion uses a sprocket drive at the rear of the tank and an idler, or return wheel, at the front. The sprocket is a multi piece design with a main body machined from solid aluminium bar, and two bolt on sprocket rings produced by laser cutting. The sprocket is fixed to the gear shaft using our standard taper lock bush arrangement. The Idler wheel is very similar, although not identical, to the one fitted to the Comet. This features a one piece wheel bolted to a central hub that houses the bearings.
Continue ReadingThe turret casting for the new Centurion arrived from the foundry this morning. It really is a very nice piece, and quite substantial. The raw casting weighs 12kg. Here is Gill with the casting, and some detail shots.
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Here are the lower and upper front plates. Both are 12mm thick and are machined for various fixings and mountings. Both plates have yet to be machined on the top and bottom edges to produce the matching angles. These plates together with the two rear plates, hull sides and floor form the basic hull structure. They have been cut from sheet using the laser cutting process, which has produced very clean edges.
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Continue ReadingAt 1.16 metres long the hull sides have to be carefully positioned in the largest machining centre to ensure that we can reach all the features in one single operation. There are fixing holes for the bogies, and for five of the six roller housings (the sixth is mounted on the drive case). There are the fixing holes for the hull plate brackets at the front and rear, for the hull strecthers and deck supports and for the drive case. Finally there are bores cut through for the exhaust and for the drive shafts.
All of the sheet metal for the mudguards and various brackets etc are laser cut from mild steel sheet. The main hull plates are laser cut from aluminium alloy sheet using the same laser cutting process. The laser cutting machines are programmed using digital information that we send to the contractor via e-mail. This way we can buy in materials profiled to shape for anything up 12mm in ally and 20mm in steel. Here is Gill holding one of the new Centurion hull sides to demonstrate the sheer size of the parts for this new tank. This hull plate is 1.16metres long.
Here is the first trial assembly of the Horstmann bogie. The fit and operation of the swing arms is just right. The spring assembly fits well but the rate looks to be a little low. We are using a commercially available coil spring for this design and have the option to increase the rate in quite fine steps. This also gives us the option to adjust ride height on these bogies. We can also adjust the spring end caps to give us the final setting.
After a short break for the holiday weekend, we have returned to continue with the build of the Centurion prototype. More particularly with the three turret bins. The ally has now been machined to the correct overall shape, and here is the first part set in the machine to do the angled face and the fixing for the piano hinge.
The other two bins have also been milled out to shape, and are waiting thier turn for the angled face op. All should be finished by tomorrow, ready for vibratory deburring.
