S
SteveO
Guest
That looks superb Mick!
Mickoo's BR modelling
- Thread starter mickoo
- Start date
mickoo
Western Thunderer
LOL, err no etching, all scratch built
I simply use CAD to draw the parts to scale from the GA's, then I print them out 1:1 scale (1:43.5 real world) on an A4 sheet, cut them out and stick them onto the raw brass with double sided tape and then cut it out. I may reconsider double sided tape as it tends to lightly clog the cut with the adhesive and backing medium sometimes.On the Standard 5 the cab and frames were CAD worked as was the firebox front and rear bulkheads, the skin was hand cut (as were a few other sundries) and formed by hand, which was a real pain and took three attempts to fold correctly. The 4P frames, tank sides, cab front and rear were CAD worked, the rest was all cut from raw brass with scribed marks. Simple square shapes are all scribed and cut as are simple lines of rivets (marked and punched), more complex parts are quicker CAD drawn and stuck on, including complex rivet patterns.
The CAD bit is the easy bit, doesn't take more than a few hours to draw the parts, it's the cutting out that's dreadfully tedious and then filing neat
I reckon all in all, to do the Standard 5 chassis as above, has taken about 12 hours from start of CAD to soldered up.I do hope to have both the 4P and Standard 5 as sprung rolling chassis (drivers only) by next Sunday for the yearly Xmas bash at West Mersea, hopefully Slaters will deliver my wheels before then.
mickoo
Western Thunderer
Yup, I tension my blade tightly which reduces breakages significantly, the double sided tape can clog the blade which makes you frustrated and thus break blades, but generally I don't have an issue with the blades if I take it easy. I tried 20 and 40 blades on the double 25thou frames but ended up breaking too many so went back to the 60 and rarely break one now, takes a bit longer but less chance of a breakage.
The Std5 frames came out really well so I'm going to bite the bullet and whizz some 7P Brit frames up, stretchers an all, always liked the raw Brit frames, a sort of symmetry in engineering.
I'll also have to break out Studio Max shortly and whip some fireboxes & backheads up for 3D printing and I also want to do the roller bearing castings that encase the main driver bearings, they're pretty much the same for Std5 and Brits and late build Black 5's
Len Cattley
Western Thunderer
Hi Mick love the idea of what you are doing with your frames, is there any chance of you doing some Rebuilt Royal Scot frames and stretchers in S7 for me mate?
Len
Len
mickoo
Western Thunderer
And now with smoke box, I do hope all the rivets line up LOL, I'd hate to have to make another!
Added a boiler profile from thick card, basically to make sure it all lines up and the base of the smokebox is the right height in relation to the firebox, so far it all seems to be in alignment, though....my stretcher under the smokebox is a touch too far aft by about 2mm but being as it's all one piece I think it'll have to stay like that, fortunately it's an area that isn't readily visible.
The next step is further card templates in plan form to check the boiler/firebox join width, I.E a card cruciform to represent the boiler and a circular end piece to see if the firebox follows the boiler diameter, looking at it right now, it doesn't look like the lower form will follow the boiler diameter.
Added a boiler profile from thick card, basically to make sure it all lines up and the base of the smokebox is the right height in relation to the firebox, so far it all seems to be in alignment, though....my stretcher under the smokebox is a touch too far aft by about 2mm but being as it's all one piece I think it'll have to stay like that, fortunately it's an area that isn't readily visible.
The next step is further card templates in plan form to check the boiler/firebox join width, I.E a card cruciform to represent the boiler and a circular end piece to see if the firebox follows the boiler diameter, looking at it right now, it doesn't look like the lower form will follow the boiler diameter.
mickoo
Western Thunderer
Len, I really don't think you want my bodges LOL, besides, although I have the Royal Scot GA's I've no photos of stripped down real loco frames, they are essential to get anywhere close I'm afraid.
Len Cattley
Western Thunderer
Hi Mick don't run your-self down your modelling is fantastic. have you got The Power of the Royal Scots by David Jenkinson in it there is some pictures of the workers building one of the Scots with frame details, these are for the original Royal Scot but with the wild swan book you could work-out what was different between the two. Sorry mate to keep going on about this, (Obi-wan kenobi your my only hope) 
Len
Len
David Taylor
Western Thunderer
I don't see any bodging going on here. I'm stunned you cut and fit all that without etching. I can't get gaps less than about 1mm wide whenever there is a curve involved!
Good idea with the boiler profile too.
David.
Good idea with the boiler profile too.
David.
mickoo
Western Thunderer
All smoke and mirrors LOL, it is a kind of etching, just that the piercing saw is the etching agent, the preparation in artwork is the same, print out and stick on and then just follow the pretty lines, there are no tabs and slots so it takes a little imagination holding stuff together for the first one or two solder dabs, then it's just a case of running a seam of solder along the joins to make firm.
Curves are difficult, I tend to make over size and then slowly file back to shape, rather than cutting to where I think it might or should be....it rarely is!
Forming a constant radius is the hardest and with precision, especially something like cab side sheets where both sides have to be identical and trust me, the two models above have produce their fair share of waste material thus far LOL.
Steph Dale
Western Thunderer
Groan - oblique cones. I remember working out the net for cutting one out as part of my GCSE in CDT. What a pain. Still not all that easy in 2D CAD, but you may well be able to create in 3D and unroll it to create the shape? These days one has a trick after modelling German prototypes for so long (which tend to have very subtle cones in their boiler cladding) and it's very close to what you're doing at the moment...
Steph
Steph
mickoo
Western Thunderer
Hi Mick don't run your-self down your modelling is fantastic. have you got The Power of the Royal Scots by David Jenkinson in it there is some pictures of the workers building one of the Scots with frame details, these are for the original Royal Scot but with the wild swan book you could work-out what was different between the two. Sorry mate to keep going on about this, (Obi-wan kenobi your my only hope)
Len
Len, yes have that book and it does show the frames reasonably well, but not the stretchers, the issue is how or where do you add or draw the line at fidelity, I know where I draw the line but it will be wildly different to others, examples you have to cover
:- Full etch from say PPD or printed and cut out by hand.
:- Rivets, half etch and punched, half etched and left raised.
:- Axle boxes, simple holes for top hat bushes or slots for sprung axle boxes from another supplier.
:- Stretchers, detailed or just simple plate work, I'd probably opt for the latter as very little is seen on Royal Scots.
:- Stretchers, width, depends on bearings and axle boxes and side play, I run with very little but am shy of 1:1 because I am using top hat bearings who's 'hat' is 1mm thick so my frames are just shy of 1:1 width over outside faces, I may change that technique on later builds.
:- Inside valve gear, added or not.....effects stretchers.
:- Bogie stretcher platework, method of fixing bogie...methods of fixing body even.
:- Interface with rest of kit, footplates, smokebox saddle, cabs etc.
Finally once you've done all that your going to have to reduce the width of parts like cylinder faces, motion brackets etc. If you already have a kit then it may be simpler to just copy their stretchers and add on the extra width required, just some food for thought
mickoo
Western Thunderer
Just been there LOL, I did O level Tech drawing, passed at grade B, was about the only thing I was good at at school! It was easy back then but not so now, just Googled and gave up, the general trend is to make a cruciform or simply roll some cardboard to a near enough shape and copy onto brass, so long as the circumference is correct at each end I can trim back to give the correct oblique cone shape.
In this instance, working smarter is seriously working harder, for me, near enough and then hand trim, whilst a little neadathol it is certainly the more attractive option right now
Dog Star
Western Thunderer
Um, possible pedant mode alert required. Does your oblique cone give you a feeling of "frustrum - ation"?
I recollect seeing a method of developing a taper boiler shape in a book about model loco construction circa 1975... if of use to you Steph then I can try to find the book again - after all, there can be only so many piles of books through which I have to search!
mickoo
Western Thunderer
I found this earlier, which looks the simplest way to achieve a mathematical solution....until I read it in depth.
http://www.nmra.org/member/sites/default/files/datasheets/MotivPwr/D4i.PDF
I'm fairly confident that by the time I've worked out how to do it mathematically and cut to shape I'd have completed the hand crafted trial fit and error one by a significant margin LOL
http://www.nmra.org/member/sites/default/files/datasheets/MotivPwr/D4i.PDF
I'm fairly confident that by the time I've worked out how to do it mathematically and cut to shape I'd have completed the hand crafted trial fit and error one by a significant margin LOL
Steph Dale
Western Thunderer
Thanks Graham,
It was one of those 'it might come in handy' things, so I've still got my drafting manuals to refer to.!
Steph
Len Cattley
Western Thunderer
Isn't that the book written by Guy Williams?
Len
Len
Len Cattley
Western Thunderer
Hi Mick, had a look on Flickr and there are some pictures of 6100 being rewheeled good view of frames and stretchers done in 2010, will phone up The Crewe Heritage Centre and find out where it is based maybe I can get some photo's. Also I can't seam to find the area where there was talk about CAD programmes, can you remember who's topic it came under?
Sorry to be a pain in the but.
Len
Sorry to be a pain in the but.
Len