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E4 construction - we have a rolling chassis

Fen End Pit


A few weeks work and progress can definitely be seen on the E4. I'd been concentrating on the body but today was the day to try and get some wheels in place. The loan of a GW wheel quartering jig from Middlepeak Tool Hire made this so much smoother. Being original Alan Gibson wheels these had the hole already drilled for the crank pins, another help when putting things together. You'll see from the photograph of the underside that the chassis is built using 'continuous springy beams' with High Level kits horn blocks and spring carriers. I did some tweaking this morning before putting it all together to get the handrail knobs that support the beam on the chassis better in line with the holes in the spring carriers. The result is that the spring is now straight in the horizontal plane which I think will help the springing, certainly it avoids the spring introducing pressure on the hornblocks to bow 'in or out' at the bottom.


Having constructed the chassis and fitted the hornblocks using the coupling rods as a jig is was very satisfying that the rods fitted on the wheels first time and rotated without any binding at all. I haven't had to introduce any 'slop' additional clearance into any of the crank pin holes at all. The bearings are a good sliding fit with very little movement front to back which helps.




The beams aren't completely continuous as being a 2-4-0 there is a considerable height difference between the axle of the front wheel and driving wheels. I've put a separate spring beam over the front axle while the drivers have the springs under the axle (actually just like the prototype!). I'm treating the chassis a bit like an 0-6-0 though from the point of view of side play on the wheels, The front and rear axles don't have very much at all with just a little introduced onto the centre axle but removing the plastic boss on the back of the Gibson wheel to give about .5mm.




The superstructure is being built in two parts to allow the motor and gear train to be well hidden. The boiler is designed to slide onto the front of the cab and then get bolted onto the footplate. This has taken a bit of fiddling but I think it is going to work. The High Level gearbox helpfully allows you to remove the motor without having to take the worm gear off the shaft.




I did have one of the 'oh $%1t' moments this morning when I found that the cab floor had pushed the inside of the cab too far apart so that there wasn't really enough clearance for the back-to-back of the rear wheels. Unfortunately there was nothing for it but to take the floor out, file it a little narrower and then refit pulling the inside of the cab lockers in slightly, It only needed about .75mm to give some clearance. In the process some of the soldering around the cab sides came apart which is why there is more solder showing around the footplate. This will get cleaned up later.




When I said 'Rolling Chassis' I meant it, You can actually push the loco along with you finger now and it is free enough to roll with the rods not binding.




The reversing lever is fitted to the footplate as will the Westinghouse pump which is on the right hand side of the loco. This side also has a pair of handrail knobs on the smokebox while the other side has only one. This is because the handrail concealed a rod to drive a little crank (sorry to be so technical).





Getting dangerously close to fitting the motor and trying to apply some power. For now I'll quit while I'm ahead.



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