mlgilbert30 wrote:.....Obviously something is quite wrong with the chimney master. It could be the top flange is too small but my feeling is that the waist is far too fat. In addition I'd say there needs to be more height to the lip on the top. What I don't know at the moment is how it could have turned out like this.......
It looks as though the sample is half-finished - as though it had been on the lathe for a while, and then the operator got distracted before completing the rest of it.
On a recently purchased sample the Craftsman chimney isn't a bad shape when viewed from the front but it looks too skinny when viewed from the side. The reason for this can be seen in the third photo (apologies for it being slightly out of focus). The ovality is presumably due to worn moulds or poor processing. Obviously a degree of cleaning up is required with whitemetal castings but on this chimney it would need to be excessive. I think you'd end up with a Weight Watchers version of a GCR chimney.
My recollection of the Craftsman dome is that the shape is a bit iffy but I don't have an example to look at. Having said that the overiding point here is why would or should you feel it necessary to go out and buy additional parts (what I'd call baseline parts rather than optional extras) when you have paid £150 for a kit? Real credit is due to Peter Stanger for taking on board the comments made here (that I have summarised to him) and agreeing to remake the masters based on new information supplied to him. On that subject I scanned the original GCR chimney profile last night and checked the 3D model against it. I'm pleased to say that it seems to be just right.
UPDATE: The Isinglass drawings turned up today and the dimensions agree with the 3D model. Some additional detail on the internal diameter taper is shown which is not on OPC ref 13118 for some reason.
Cheers....Morgan
Last edited by 45609 on Thu Feb 02, 2012 9:39 pm, edited 2 times in total.
Indeed I have and he has acknowledged receipt. A fairly lengthy reasearch commentary went along with it so I don't expect a detailed response for a couple of days.
So here is my detailed drawing for the LNER "GCR Style" or "Modified" Gorton chimney. If there is anything that jumps out at you as not being right then now is the time to speak up as we are rapidly converging to a solution on this chimney.
Thinking laterally about this last night I decided to read around the subject a little and picking up my RCTS volume 6A (tender classes O1 to P2). It soon became apparent that it would be worthwhile measuring the chimney on my Bachmann O4. Why? The O4 boiler and smokebox outer diameters are the same as the A5 and the RCTS volume mentions similarities in chimney fit between the 2-8-0 and 4-6-2T. Also I reasoned that Bachmann will have measured the preserved O4. Now I know what they say about preserved not necessarily being the same as original but nontheless the results were startling. The key dimensions of the Bachmann chimney came out virtually identical to those I had modelled up in the attached drawing. Draw [sic] your own conclusions.
