Scale7JB Posted February 10, 2010 Share Posted February 10, 2010 I've got a blog, but getting a bit bored of the blog format to be honest, so thought I would start this thread here... It's been in the planning for a little while, and can't see it being the fastest build ever, but it started this morning... A scratchbuilt (first time) Great Eastern N7/3 in Scale7 for use on the infamous West Mersea layout. So far I have begun work on the frames which will be correct as per the prototype. Most kits have the top and bottom half of the frames separate as the prototypical width would be far too wide for standard 32mm gauge, but as this is dead scale, it allows the actual shape of the frames to be cut out.... which is nice ! The frames will be cut out on a Pantograph milling machine, so I have created a Plasticard template from the drawings of the GERS, which will also allow for endless sets of frames to be produced. The template is 3 times larger than necessary for use on the milling machine, so it will be super accurate when it is down to 7mm/ft size. Below is a shot of the plasticard template, and the workbench cleaner that it has ever been before JB. Link to post Share on other sites More sharing options...
alcazar Posted February 10, 2010 Share Posted February 10, 2010 Ah, the Pantograph profiling and milling machine. A work of art, a beautiful tool, what more can I say? I spent hours on one at training college, making stuff as varied as a centre console for a rally car, some speakers, and brass nameplates for places in Nottingham and Worksop. Link to post Share on other sites More sharing options...
Scale7JB Posted February 10, 2010 Author Share Posted February 10, 2010 A centre console for a rally car ? That sounds very interesting... Just incase this is too foreign an engine for some http://en.wikipedia.org/wiki/File:LNER_Class_N7.jpg JB. Link to post Share on other sites More sharing options...
dikitriki Posted February 10, 2010 Share Posted February 10, 2010 Hi JB Excellent stuff. I've always fancied fabricating components with a pantograph miller, so I shall look forward to reading your experiences. Lots of lovely pipework to get your teeth into. I can't remember why, but I took loads of photos of the N7 at Sherringham, just because it was there and I had my camera I think. So to encourage you along the way..... Richard Link to post Share on other sites More sharing options...
Buckjumper Posted February 10, 2010 Share Posted February 10, 2010 Careful. The photos are of the preserved N7/4 which were rebuilds of the original 22 GE locos. These had considerable detail differences, both major component parts as well as minor details, with the N7/3 JB is proposing to build. He's already run into a bit of a problem with the frames - but he'll explain... Link to post Share on other sites More sharing options...
dikitriki Posted February 10, 2010 Share Posted February 10, 2010 Careful. The photos are of the preserved N7/4 which were rebuilds of the original 22 GE locos. These had considerable detail differences, both major component parts as well as minor details, with the N7/3 JB is proposing to build. He's already run into a bit of a problem with the frames - but he'll explain... Well I don't know. These foreign locos. It said N7 on the packet Link to post Share on other sites More sharing options...
Rob Pulham Posted February 10, 2010 Share Posted February 10, 2010 I look forward to seeing your progress on this JB I am trying my hand at small bits of scratch building but I would love to have a go at a 7mm loco (it's on the things to do before I die list) Link to post Share on other sites More sharing options...
Scale7JB Posted February 10, 2010 Author Share Posted February 10, 2010 Thanks for the intro Adrian... Yes the first problem and a fairly major one at that... As Adrian mentioned there was more than one version of the N7, in fact I think there were 5 updates after the original. Major differences being the firebox and loading gauges etc, but the problem I have encountered is that after the original couple of batches of the N7 and N7/1 the radial truck (which I was quite looking forward to modeling) became a pony truck. I shall have to find drawings of the revised frames and go from there, so where you see the cutout for the radial truck on my plasticard master above, disregard it. A schoolboy error at best ! One might say.... "back to the drawing board" ?? JB. Link to post Share on other sites More sharing options...
gobbler Posted February 10, 2010 Share Posted February 10, 2010 I'll be watching this thread with interest I'll be scratchin an N7/4 in 4mm for my Southminster branch layout. regards, Scott. Link to post Share on other sites More sharing options...
Adrian Posted February 11, 2010 Share Posted February 11, 2010 Excellent stuff. I've always fancied fabricating components with a pantograph miller, so I shall look forward to reading your experiences. <mode AOL=on> Me too! </mode> Although I've been tempted by some of the developments in CNC pantograph milling. I've sketched out a CNC miller design which is fairly compact but gives a good travel on the cutting bed sufficient for 7mm work. The usual pantograph machines are quite bulky with all the linkages plus the overhead of cutting out all those plasticard templates. A CNC version would be much more compact and easier to modify the templates. It's another one of those projects I really must get round to doing something about. So anyway looking forward to this build - so how are you going to improve on working reverser and brakes on this one? Have fun Adrian (Cherry) Link to post Share on other sites More sharing options...
Scale7JB Posted February 11, 2010 Author Share Posted February 11, 2010 How am I going to improve on the working reverser and brakes ?? Answers on a postcard to.......... please, suggestions would be great.. Regarding the cutting out of the plasticard templates, I think in total, the template that I cut earlier on only took a couple of hours, though I'm sure that getting to grips with the Alexander milling machine might take a bit longer than that. Ideally i'll be able to solder two sheets of nickel silver together to create two perfectly accurate side. I just need to make sure that my connecting rods are accurate after that... One thing that this build will include is roller bearings after the success of the K2 and it's very free runnning. JB Link to post Share on other sites More sharing options...
Pugsley Posted February 11, 2010 Share Posted February 11, 2010 Interesting project B) Is there any reason that you're going for pantograph milling rather than etching? Link to post Share on other sites More sharing options...
Scale7JB Posted February 11, 2010 Author Share Posted February 11, 2010 Interesting project B) Is there any reason that you're going for pantograph milling rather than etching? Why milling? For a number of reasons really... At our group we have two pantograph milling machines, which have been bought specifically for doing this. Cost as it should be a lot cheaper than etching (so long as we don't snap too many milling bits) Also accuracy which should be a better on tolerances than with etching I would imagine. Looking forward to trying the machine out, I'll let you know how it goes for sure.. Might even try and get a video if it works perhaps.. JB. Link to post Share on other sites More sharing options...
Horsetan Posted February 11, 2010 Share Posted February 11, 2010 .....As Adrian mentioned there was more than one version of the N7, in fact I think there were 5 updates after the original. Major differences being the firebox and loading gauges etc, but the problem I have encountered is that after the original couple of batches of the N7 and N7/1 the radial truck (which I was quite looking forward to modeling) became a pony truck..... The radial truck wheels also decreased slightly from 3'9" dia. to 3'6". Also a change from RHD to LHD, plus differences in the rear cab windows. N7/2 & N7/3 also had cabside windows placed closer to the cabside openings. Difference in the steps inset into the bunker sides: N7/2 & N7/3 had two per side, whilst N7/1/4/5 generally had one. (Slightly off-topic note: For those building the 4mm scale etched Connoisseur N7/3 kit, do compare it with a good scale drawing (Isinglass can supply). Whilst trying to convert from N7/3 to N7/4, I found that the bodysides - i.e. tanks / cabsides / bunker - were a bit too short!) Link to post Share on other sites More sharing options...
Scale7JB Posted February 11, 2010 Author Share Posted February 11, 2010 Had to pop this in here... http://www.britishpathe.com/record.php?id=1165 Link to post Share on other sites More sharing options...
Scale7JB Posted February 11, 2010 Author Share Posted February 11, 2010 The radial truck wheels also decreased slightly from 3'9" dia. to 3'6". Also a change from RHD to LHD, plus differences in the rear cab windows. N7/2 & N7/3 also had cabside windows placed closer to the cabside openings. Difference in the steps inset into the bunker sides: N7/2 & N7/3 had two per side, whilst N7/1/4/5 generally had one. (Slightly off-topic note: For those building the 4mm scale etched Connoisseur N7/3 kit, do compare it with a good scale drawing (Isinglass can supply). Whilst trying to convert from N7/3 to N7/4, I found that the bodysides - i.e. tanks / cabsides / bunker - were a bit too short!) I'm going to need a Yeadons ! JB. Link to post Share on other sites More sharing options...
dibateg Posted February 11, 2010 Share Posted February 11, 2010 Interesting project JB, I look forward to watching it develop - how about a moving crew? !! Link to post Share on other sites More sharing options...
Horsetan Posted February 11, 2010 Share Posted February 11, 2010 I'm going to need a Yeadons ! And RCTS 9A Link to post Share on other sites More sharing options...
gobbler Posted February 11, 2010 Share Posted February 11, 2010 i've got the yeadons register for the N7, a 'must' i reckon'! Scott. Link to post Share on other sites More sharing options...
Pugsley Posted February 11, 2010 Share Posted February 11, 2010 Also accuracy which should be a better on tolerances than with etching I would imagine. You should be able to get tolerances of one thou through etching, so would think it was comparable. Looking forward to trying the machine out, I'll let you know how it goes for sure.. Might even try and get a video if it works perhaps.. I look forward to seeing how you get on. B) Link to post Share on other sites More sharing options...
alcazar Posted February 12, 2010 Share Posted February 12, 2010 If you've never used one, the trick is to take it steady, don't attempt to rush, or force the cut, and ALWAYS keep your eye on the stylus, not the cutting head. YOU guide the stylus, the machine guides the cutting head. Link to post Share on other sites More sharing options...
Scale7JB Posted February 12, 2010 Author Share Posted February 12, 2010 If you've never used one, the trick is to take it steady, don't attempt to rush, or force the cut, and ALWAYS keep your eye on the stylus, not the cutting head. YOU guide the stylus, the machine guides the cutting head. Thanks Alcazar, I shall bare that in mind, though I was thinking that i'll need to keep an eye on the cutting edge to make sure that I'm not chomping too much out and risking snapping the cutting bit. Do you have any tips about how to mount the metal to the cutting platform? I think someone in the group has tried to use the machine with some E4 frames that he made up, but the metal to be cut moved and so snapped the cutting bit... Any advice from people with experience of these machines would be GREATLY received !! :icon_thumbsup2: JB. Link to post Share on other sites More sharing options...
Scale7JB Posted February 14, 2010 Author Share Posted February 14, 2010 Due to a current lack of N7/3 drawings, this build will now be for the earlier N7/1 which after around '44 (I think) had it's firebox changed to a round topped version, and became an N7/5. At a later date, I may well create another template of the N7/3, so that we can have a few version of the class running on West Mersea.. Thankyou to Buckjumper for the ever endless amount of information! :icon_thumbsup2: More news when it comes.. JB. Link to post Share on other sites More sharing options...
Miss Prism Posted February 25, 2010 Share Posted February 25, 2010 Here's a CSB plot for an N7 if you need one (a Wills kit awaits for me...) - just multiply the figures by 7 and divide by 4. Link to post Share on other sites More sharing options...
Scale7JB Posted February 25, 2010 Author Share Posted February 25, 2010 Thanks Miss Prism. A CSB is something that I have wanted to try for a bit, just so long as it can't be seen under the boiler, but then the working inside valve gear should hide a few things. Definitely will give it some thought! JB. Link to post Share on other sites More sharing options...
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