Class 22 Diesel (next project)

Ron I know you have described your traction engine, but the idea just crossed my mind - why not make it a showman's and have the motor as the dynamo - doing things in reverse so to speak. OK I know it is not prototype practise to move running the dynamo, but the engine look could be made good?

Just a thought - I'll go back to sleep now

Edited By Nick Clarke 3 on 13/06/2019 12:18:08

Hi Nick

That has in fact crossed my mind, whichever way I go the engine drive will sort of be working in reverse i.e. motor driving a geared wheel, the wheel driving gears back to the crank and the crank driving back to the piston. Driving the flywheel/crank from a top front mounted motor (dynamo) I would think quite feasible. What put me off the idea when first I looked at it was the belt drive but now having some experience of poly V belts and pulleys I dont think that an issue.

Thanks for the idea, I will give it some more thought.

Ron

Started machining the belt pulleys ready for fitting to the wheels, they need the boss removing, the width reduced to 10mm from 13mm and the bore increased from 8mm to 16mm. I turned up a stepped mandrel to centre the pulley to the wheel, the axle seat for the wheel is 1/2" dia and the main axle diameter where the pulley sits is 5/8" (16mm). I put a small hole in the centre of the mandrel which with a pair of dividers made scribing a PCD for the screw holes dead easy. The mandrel will also come in handy when I screw and fix the pulley to the wheel keeping all centered and aligned ready for fitting to the axle.

Edited By Ron Laden on 16/06/2019 16:06:36

There are a good number of Bo Bo British diesel locos and the class 22 is one of them and that is what I set out to build, but I am considering playing my "change my mind card" .

I came across a couple of older Pullman locos which have a bit more interest in the detail and shape of the body and not so often modelled as far as I know but then I found the one below.

Its a class 20 but surely a "showmans engine" in the world of diesel locomotives, not decided but seriously tempted.

The 4 axles/wheels are complete with drive pulleys fitted, the pulley wheels are not fixed to the axles yet as I have to slide on the motor mounting plates before fixing.

Well the wife is not too impressed with the shiny red class 20 loco. Upon seeing the picture of it she said "oh no its far too ornate, looks like something from a fairground, way over the top" I said, I know thats what I like about it. She said, "stick with the baby warship"

So there you go, thats what the wife thinks of it ....

Edited By Ron Laden on 20/06/2019 17:17:35

The 8 axle boxes are all machined apart from fitting the axle bearings but I am awaiting a 13mm drill for that job.

Put in the spring mounting holes this morning, drilled the bulk out and then finished with an endmill to leave a square seat for the spring. I must get around to making Jasons vice stop but a quick setup of an angle plate with a low level clamp added did the job.

Edited By Ron Laden on 26/06/2019 08:14:38

Sorry double post.

Edited By Ron Laden on 26/06/2019 08:11:20

The 1/8" slitting saw arrived, I was looking for a 3mm to fit my R8 / 22mm arbor but struggled to find one. Jason suggested that if I could get away with a 1/8" then ARC had them in stock though the mount hole was 1" and would need to knock up a stepped bush which I did.

The saw is for slotting the axle box spring mounts (8 off) so I set them up this morning using the 4 jaw mounted on the RT. I thought it the best way to hold them with the blade running through between the jaws it worked fine, took no time to do all eight.

Thanks Jason, I would probably still be searching for a 3mm saw at the right price.

The basic axlebox and spring mounts are done, they will need 25mm long springs which at their rating gives 3mm compression when all 8 boxes are loaded and a further 6mm of travel when running. I went with those dimensions/figures on the 0-4-0 and it works fine. The bearings are shouldered oilites, 10mm long which matches the length of the stub axles and conveniently leaves a recess for bearing caps which I will turn from aluminium.

Looking good Ron!

Thanks Jeff.

Just out of interest or for anyone looking for heavier type compression springs for axle boxes and the like I,ve put up a picture showing what I go with. I use die springs, always buy them from China via Ebay, they are good quality and there is a huge range of sizes. They are cheap as chips always come with free postage and they are usually delivered within 7 days or less.

I dont know if Chinese manufacturers/suppliers always use the same colour code for the different strengths but I,ve had the same colour springs from different suppliers and they were identical. For my use I have rated them as Blue=Medium, Red=Med/Heavy. Green=Heavy and Brown=V. Heavy.

I will probably go with red on the class 22 based on the 0-4-0 working well with 4 red springs and a AUW of 25kgs. The 22 should weigh around 50 kgs but with 8 springs.

Edited By Ron Laden on 20/07/2019 09:25:11

Edited By Ron Laden on 20/07/2019 09:26:38

Nice work!

What is the dimensions of the springs you are using?

8mm diameter x 25mm long.

As per the 0-4-0 I intend to machine the buffers in aluminium - all one piece not sprung. The 0-4-0 buffers turned out well but its not quite as simple with the class 22 as the buffer plates are not round but elliptical.

I have thought of machining them round then scribe around a template and file them to shape but it would be nice to machine them if I can, but how..? I also thought of making them round and then mount them on the rotary table and cutting with a large radius machine the two horizontal edges and then with a smaller radius machine the ends. That would still mean blending in (I think) as the two mating radius would not generate the correct shape.

So still thinking about it but if anyone cass pass on any tips or methods of manually machining an ellipse it would be appreciated.

Google 4 centre ellipse, then make a jig to hold the stocks off centre on the faceplate, this will allow machining of 2 of the curves, but then you are into filing

Thanks Duncan

I sketched out the shape which is stretched a bit, I think machine it round and then cut and file to shape is going to be the easiest.

Just a thought - is the oval buffer the same width as a round one or the same height or something in between??

Also why turn it round as none of the round will remain in the finished buffer head? - why not plot some coordinates and rough it out standing on end in the mill, finishing with the file.

Edited By Nick Clarke 3 on 24/07/2019 08:38:31

Edited By Nick Clarke 3 on 24/07/2019 08:39:06

Nick, actually I will not be machining it round the complete one piece buffer assy is coming out of 50mm bar so it starts off round.

Ron

Working on the design this morning I wondered if I was proficient in CAD would it make things much easier..?. I fear though I am too long in the tooth to start now and I dont have a leaning towards computers. So its paper and pencil which I understand and for me it seems to work, though I dont produce proper drawings (unless I put something out) but more in the way of working sketches.

Edited By Ron Laden on 26/07/2019 08:31:58