7mm Mickoo's Commercial Workbench
- Thread starter mickoo
- Start date
mickoo
Western Thunderer
The rest of the week was spent chugging along with the N, the battery box is work in progress, needs to be a bit deeper and shallower to sneak under the reach rod and closer to the firebox, the timing reservoir failed in the print so another test on going.
The kit smoke deflectors are for the scrap bin so new scratch built ones shortly and other small details to add before dropping below decks to round out the motion.
The kit smoke deflectors are for the scrap bin so new scratch built ones shortly and other small details to add before dropping below decks to round out the motion.
RichardG
Western Thunderer
I see you have swapped the side rods around and I am intrigued. Did you really just "swap the rods to suit" or did you open out the holes in the rods so the wheels would still rotate?
I ask because on my own builds I am trying to put two or three thou of clearance around my crankpin bushes. Enough to accept a drop of oil. I doubt the axle spacing on the B12 is "identical" within such a tolerance; and so an answer will give me an idea of the clearances a pro builder provides around their crankpin bushes.
mickoo
Western Thunderer
Yes I just swapped the rods over and no I did not open the holes out.
I don't make my frames the same as everyone else, too much leeway in my view. I make one set of rods (the master), I use those to set up the jig (very short stubs) and then fit the bearings into each side frame separately, then I assemble the frames. I then use the same jig settings to make the second rods so I know they're identical to the first and the axle spacings.
The most important bit is to ream and fit the knuckle pin with the rods on the jig, most people don't and just rely on the etches to be accurate and ream in their hand, most of the time the etches are okay but it only needs the drill or reamer to wander a fraction and your 2-3 thou tolerance is pie in the sky.
It's not unusual to find the fixed second set of rods not lining up with the jig (after the master set is made), drill/reamer wander, etch incorrect etc, in that case I open out and fit micro bore tube in the rod and centre it before soldering in place.
Tolerances are subjective, if your model is plate glass micro layout centric or display case rolling road then they can be tighter, if you have side and vertical play then you need more tolerance, if you don't then the model will soon do it for you as it pounds around your 40' x 20' layout on a rake of twelve coaches.
I don't make my frames the same as everyone else, too much leeway in my view. I make one set of rods (the master), I use those to set up the jig (very short stubs) and then fit the bearings into each side frame separately, then I assemble the frames. I then use the same jig settings to make the second rods so I know they're identical to the first and the axle spacings.
The most important bit is to ream and fit the knuckle pin with the rods on the jig, most people don't and just rely on the etches to be accurate and ream in their hand, most of the time the etches are okay but it only needs the drill or reamer to wander a fraction and your 2-3 thou tolerance is pie in the sky.
It's not unusual to find the fixed second set of rods not lining up with the jig (after the master set is made), drill/reamer wander, etch incorrect etc, in that case I open out and fit micro bore tube in the rod and centre it before soldering in place.
Tolerances are subjective, if your model is plate glass micro layout centric or display case rolling road then they can be tighter, if you have side and vertical play then you need more tolerance, if you don't then the model will soon do it for you as it pounds around your 40' x 20' layout on a rake of twelve coaches.
mickoo
Western Thunderer
Finally finished and on it's way for delivery at Kettering, it's taken just under three years and most of that was sat here and there waiting for opportune times to deliver/collect from paint (Paul Moore) and weathering (Neil Podbery), let alone fitting it in with their busy schedules.
Nothing ever gets posted so it can be a juggle organizing hand deliveries etc but on the whole projects are turned around quicker.
Nothing ever gets posted so it can be a juggle organizing hand deliveries etc but on the whole projects are turned around quicker.
mickoo
Western Thunderer
To be fair I've had really expensive stuff from the states and it's all arrived just fine, I do ship one model a year to a client but it goes in three boxes, the loco box (well packed), an outer box (well packed) and a third bash it to bits box (well packed). It's about five times the size it needs to be but so far they do get there unmolested.
cmax
Western Thunderer
Arise Sir Brian, thats another cracking build Mick.
mickoo
Western Thunderer
Quick N class update as I may not get time to do a completed one before heading out the door on Friday.
Essentially topsides all done, just needs valve gear doing, typically a days work but given the woes so far might take a bit longer.
New deflectors with half round beading ate up a lot of time as did the oil line covers down the sides of the firebox with fixing straps, the kit ones were much too weedy and too short, well they were the same length which was fine for the RH side with the reach rod cover, but the LH was 6 mm too short.
New 3D battery box and timing cylinder and I had a spare Finney half etched battery box cover which pimps it out a bit more, just need to add the little 0.4 mm spigots to complete but it's not fixed so can be done during paint.
Front washout plugs are scratch built, there are spare castings in the kit but they have a raised edge/flange that suits the firebox, boiler ones are flush so inserted lengths of 2 mm OD x 1.5 mm ID tube and then dropped in 1x1 mm bar for the plug and left the top slightly proud.
The kit vacuum ejector smokebox elbow isn't, just bend 1.6 m wire and poke in the hole...uuuugh, I repurposed a LNER casting by taking off the bolted flange and tweaking the shape, not perfect but 90% accurate. The steam manifold in the kit is a lumpen mess, cling it made as it hit the steel bin, a new 3D one with correct pipework will be added after paint as it's in a prone place for damage and it allows Warren to get behind for a decent finish.
Essentially topsides all done, just needs valve gear doing, typically a days work but given the woes so far might take a bit longer.
New deflectors with half round beading ate up a lot of time as did the oil line covers down the sides of the firebox with fixing straps, the kit ones were much too weedy and too short, well they were the same length which was fine for the RH side with the reach rod cover, but the LH was 6 mm too short.
New 3D battery box and timing cylinder and I had a spare Finney half etched battery box cover which pimps it out a bit more, just need to add the little 0.4 mm spigots to complete but it's not fixed so can be done during paint.
Front washout plugs are scratch built, there are spare castings in the kit but they have a raised edge/flange that suits the firebox, boiler ones are flush so inserted lengths of 2 mm OD x 1.5 mm ID tube and then dropped in 1x1 mm bar for the plug and left the top slightly proud.
The kit vacuum ejector smokebox elbow isn't, just bend 1.6 m wire and poke in the hole...uuuugh, I repurposed a LNER casting by taking off the bolted flange and tweaking the shape, not perfect but 90% accurate. The steam manifold in the kit is a lumpen mess, cling it made as it hit the steel bin, a new 3D one with correct pipework will be added after paint as it's in a prone place for damage and it allows Warren to get behind for a decent finish.
Pencarrow
Western Thunderer
I can smell the midnight oil burning from up here in the north palAdditional details really lift the base model, looking forward to seeing this one painted and weathered hopefully
It's an N Class destined to run around a North Cornwall line - of course it will be weathered! Heavily...
mickoo
Western Thunderer
Pencarrow
Western Thunderer
mickoo
Western Thunderer
I have literally no idea Chris.
Podders is going to have a field day trying to replicate that mess
Personally I think it's too much, authentic but not my cup of tea.
mickoo
Western Thunderer
Try as I might the clock keeps ticking but finally the last piece of scratch building on the N is complete, I've been putting it off until I had no choice, fabricating the parts wasn't hard, it was how and and where to attach so I didn't make life difficult later on post paint.
The cross head is captive and I didn't want to leave it and the connecting rod flapping around during paint so there was a natural joint where it meets the motion bracket, that means the spray guard could not be fixed between the cylinder block and motion bracket and adding the footplate bracket was problematical.
In the end the guard is fixed to the motion bracket and footplate brackets, these have small hooks of 0.8 mm wire that drop into small notches in the frames.
Tolerances are not that tight to be fair as the guard shape is profiled to clear any moving parts naturally, I did have to take a lot off the back of the crosshead casting, it was very thick and over scale.
I paint my chassis here so the rest of the motion can be added whilst the important parts are away for paint, body, cylinder block and tender. Some of the motion is build, add, paint, build some more, paint, add, build, paint yada yada yada so there's not point busting a gut to complete all the valve gear and then undo it to paint later.
Sharp of eye will note no engine springs, they're 3D printed but will be added once the chassis is stripped down, cleaned in celly thinners (which eats 3D prints) and then fitted.
The cross head is captive and I didn't want to leave it and the connecting rod flapping around during paint so there was a natural joint where it meets the motion bracket, that means the spray guard could not be fixed between the cylinder block and motion bracket and adding the footplate bracket was problematical.
In the end the guard is fixed to the motion bracket and footplate brackets, these have small hooks of 0.8 mm wire that drop into small notches in the frames.
Tolerances are not that tight to be fair as the guard shape is profiled to clear any moving parts naturally, I did have to take a lot off the back of the crosshead casting, it was very thick and over scale.
I paint my chassis here so the rest of the motion can be added whilst the important parts are away for paint, body, cylinder block and tender. Some of the motion is build, add, paint, build some more, paint, add, build, paint yada yada yada so there's not point busting a gut to complete all the valve gear and then undo it to paint later.
Sharp of eye will note no engine springs, they're 3D printed but will be added once the chassis is stripped down, cleaned in celly thinners (which eats 3D prints) and then fitted.
Pencarrow
Western Thunderer
Out of interest does anyone know how common the splash guards seen on the N Class feature other types of loco?
Until Mick and I started talking about this build last year, I hadn't really noticed them, even on the Ns. In my defence, all my other N Class are the 4mm Bachmann version and they certainly didn't have them!
Until Mick and I started talking about this build last year, I hadn't really noticed them, even on the Ns. In my defence, all my other N Class are the 4mm Bachmann version and they certainly didn't have them!
mickoo
Western Thunderer
They do feature on other locos and I have fitted them (I think but not where), I've not see them on a N class model before and it only seems to appear on the frame rebuild engines with separate cylinder blocks and outside steam pipes.
I'll have a dig around later to try and remember where I've seen them.
I'll have a dig around later to try and remember where I've seen them.
