Posted by: aj427 | October 11, 2013

J50 Test Prints

My Gresley J50 CADs have been almost ready for some time and a flurry of activity adding final details and sprueing items together resulted in a test print being ordered from Shapeways. The test comprised of the J50/3 body (to suit the Bachmann Pannier chassis), the J50/2 body as well as a prototype chassis for the J50/2 and a cab interior. The results are generally very good but there are some damages partly due to the single print and the items being crushed together into the too small bag and partly due to some design weaknesses. For example, all of the steps have been broken. This is I think a design fault on my part – pushing the minimum wall thickness – and they will need beefing up for future models. Also one of the guard irons has been damaged. I did expect this part to be too delicate so I’m not surprised. Finally one of the suspension assemblies on the chassis has been snapped off. I think this may be manhandling but the part will be beefed up anyway. The prints seem to be dimensionally stable with the axle spacing on the chassis being spot on.

J50 test-2510a J50 test-2511a

J50 test-2488aJ50 test-2490a

The J50/3 comes with a seperate underside sprue that houses a set of LNER standard buffers and undercab injector equipment. The injector equipment is very delicate but has printed remarkably well. This comes on a mounting block that sits in a slot beneath the body. The J50/3 is left hand drive which can be noted with the vacuum ejector on the smokebox. The pipework for this disappears into a recess in the curved plates that join the boiler to the tanks. This is a feature that I don’t think I’ve seen modelled on any J50 kit or scratch-built models I’ve seen. I have a wonderful picture of Bradford Bowling depot viewed from above which shows a number of J50s and clearly shows this feature. You can also just about see it on a couple of images in the Yeadon’s volume. Initial test fitting to the Bachmann chassis has proved successful with just some minor adjustments required to the print for a perfect fit. Here’s a picture – with the outside brake rods and sandboxes yet to be removed it looks like some strange LNER-GWR hybrid!

J50 test-2512a J50 test-2506aJ50 test-2499

The J50/2 again comes with a seperate underside sprue. This houses both GNR and LNER standard buffers (both types could be found on members of this sub-class). The undercab injectors are part of the main body print on a mounting plate (as per the prototype). They will need the addition of wire to represent the pipe work. The J50/2 is right hand drive and the top plates and ejector are reversed on this model. I also had printed a rudimentary cab interior, designed to slot inside for ease of painting. This is fairly basic but has printed well. I have however made an error with this as the sandbox/step is in the way to slide it in. A small adjustment with the scalpel will sort this for now. I will probably also need butcher this slightly if I decide to put a flywheel on the motor.

J50 test-2497

Onto the (highly experimental) chassis. The main frame is compartmentalised for strength and to provide ‘buckets’ for ballast weight and certainly it has come out very rigid. However, outside detail parts do seem too delicate with the damage to the spring and the guard iron the result. I can see these parts breaking further when fiddling about and adding wheels etc. These parts will need to be either beefed up or perhaps done as sprued items for future prints. Brake shoes are on a seperate sprue but these had nearly all come off. None were lost or damaged but a better sprue is in order. Fit to the J50/2 body was perfect and a quick fit with Alan Gibson wheels resulted in this.

J50 test-2500aJ50 test-2501aJ50 test-2502a

My initial thoughts on the chassis are that it’s perhaps too delicate to be done wholly as a one part item. I think the springs, guard irons and brake shoes will be done as a seperate sprue so that these items can be added later and are not structural.

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