Supporting > Vehicles & Models
2" Minnie Traction Engine
Jo:
On model Locomotives they tend to use the relatively cheap Cast Iron cylinders and liners because of the amount of use the engines get doing public running, accepting that the slight rusting between uses will be quickly rubbed off in use. Most small model traction engines are not going to be steaming/ running 8 hours a month pulling heavy loads.
Gunmetal or bronze is preferred for less used models, it is much more expensive but does not have the same level of TLC required long term.
Jo
Jasonb:
I just had a look at Blackgate sand the 2" Minnie is a CI cylinder so I would go with a CI liner loctited in. this is the same arrangement a smy 2" Fowler has.
Most locos don't tend to use liners unless someone is cutting from solid as they do not need the annulus around the liner so that steam can travel up from the boiler to the regulator ontop of the cylinder. Most small traction engines of 1" and 1.5" tend to have GM castings, most above that are iron.
Jo:
Both of my Loco's cylinders have liners. The use of Liners are good practise on passenger hauling Locos because they are easily replaced ::)
Jo
packmule:
Thanks everyone for your replies.
Yes Jason its a blackgates block so ci it is then. :praise2:
packmule:
Its certainly been a while but work is still progressing.
OK. The casting turned out to be a complete disaster, bull at a gate time.
I first machined the top flat straight out of the box without actually checking the casting :hammerbash: When I checked the thickness of the saddle it was already below what I needed as a finished size.
Consigned to the bin.
Not even comtemplating another casting I bought some thick walled steel tube and set about machining, boring out the centre to req'd size then the outside for the thickness. That done I bought a 100 x 100 steel block for the cylinder ,this was cut on the mill to fit the saddle. As the block was undersize on the width I milled it flat and silver soldered extra steel to give me the width I needed. This was then set up in the mill and both ends milled so I could place on one end and bore out for the cylinder. Following this I turned a wooden plug to fit in the cylinder so I could place in the vice and roll the block taking light cuts to shape to the radius req'd. The cylinder proper was machined from cast iron to a shrink fit and placed in the freezer over night, then heating the steel block the cylinder was quickly fitted
The ports were milled into the port face as usual practice and the cylinder was then placed in a tilting vice to drill the ways from the cylinder ends. This was setup using a simple jig with 2 equal length adjustable arms so the end of one touched the inside of the cylinder edge and the other inside the top of the milled port. Perfect on 3 ,on the last managed to move slightly and just caught the edge of the milled port but I think should be ok.
will post some images tomorrow
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