Its been some while since I started a thread, but I haven't been idle. Since getting my Simplex in Steam and doing a little tidying up work on it I've been pondering what to take on as my next long term project. I have the fancy to doing a larger tender loco, I dropped on a set of Don Young drawing for his 5" Gauge 2-6-0 Horwich Mogul otherwise known as a Crab due to its appearance. Don's drawings are beautifully detailed and have many of the features of the full sized engine, but her I hit a problem, I'm not that bothered about it being an exact scale model as long as it looks ok when its over on the far side of the track I will be happy I'm more interested in its ease of manufacture, and it being a good runner. So I will be using Dons drawings only as a guide, and will be redesigned it extensively to make it easier to make:- her are my objectives and list of constraints for the design.
Objectives:-
1:- 5" Gauge Miniature Locomotive
2:- Good Reliable Runner
3:- Extensive use
4:- Haul a minimum of 8 people
5:- Resemble a 2-6-0 Horwich Crab
Constraints:-
1:- All Features to be functional and relevant to use of a Miniature Locomotive
2:- Minimum of cast parts
3:- Make Maximum use of Don Young's design
4:- Maximum Use of laser cut parts
5:- Maximum use of commercially supplied Items (Boiler and Fittings)
6:- Simple Construction
7:- Simple and easy to maintain
8:- Transport by one person
So there we have it:-
Every project has to start some ware so I decided to start with the cylinders as I thought this would be the most difficult part to make and if I couldn't make them there was no point in taking it any further. I didn't wont to use castings I wanted to make them from a billet of cast iron, this called for a redesign of Don Young's drawing. I kept all the main critical for function features:- over all length vavle ports cylinder piston valve relationship etc, but reduce the cylinder diameter to 1 3/4" 45mm and simplified other features so that it could be made from billet.
Progress to date:-
Cutting the meehanite cast iron billet to size.
I then roughed it out on the mill and finished square using an angle plate
spotted out the cylinder and valve position using the mills DRO and located in large four jaw using a wobble bar.
Roughed out the bores.
And then set up on the cross slide and using a between centre boring bar finished the bore.
First bore done only another three to go.
That's as far as I've got.
I'll keep you posted as things progress.
Stew