Mickoo's American Modelling Empire
- Thread starter mickoo
- Start date
mickoo
Western Thunderer
Yellow stripe for me 
Back to the Roco/Atlas GP9 project, think I'm just about there now, several minor changes along the way, mostly inverse compensation so that when printed it's all square and straight.
A quick reminder/comparison from where we started to where I am now.
On the left the original high level drive line gear tower, on the right the new low drive line gear tower. One of the recent alterations was to the front and rear ends, I removed the horns that hold the side frames in place and replaced it with the depressed transom beam, I still need to shape the side frame blobs on the end to loom a bit more like a Blomberg but I won't expend a lot of energy there, just enough to appease the eye a little more.
The next change was some new wheels from Roxey Mouldings.
The original sits outside with it's super wide treads, to be fair the replacements are not accurate, I think P48 is 0.115" scale thickness, these are 0.140" and the originals are 0.200". Still, they're good enough for OW5 and I can turn them to much closer to scale but keep the same gauge; a growing trend loosely called PW5 or more accurately P48 wheels at OW5 gauge.
The cover plate is just laid on top, the new fixing holes in each corner have not been drilled yet, the original Roco/Atlas uses self tappers and they tend to spit the resin where the thread starts, not parallel with the bore but on the surface where it blows out a little circular pancake of resin. The new fixings are countersunk 10BA screws and a nut (probably in a shaped recess) on top of the block.
Internally you need to turn the axles down from 5/16" to 4.00 mm to accept the plastic gear (revised design ones to reduce splitting should be done in a few days), then you need to turn a shoulder each side down to 3.50 mm to accept the Roco/Atlas square brass bearing.
Assembled low drive line power brick, the UJ has one side (outer) at a lightly larger diameter, it's fine whilst the drive is straight but if you kick it up then the fingers around the ball just catch the top of the block so I'll add a small recess in there on the final version, I'll also put recesses for the nuts that the side plate cover screws fix into.
Temporarily fitted into the Red Caboose GP9 chassis.
The primary reason for all the effort, chopped nose GP9's and free cab floors.
Clearance with all the recent modifications is ample, in fact the chassis has slipped down a bit in the last shot so there is more than shown. The chopped nose etched cab was kind of put on hold as I couldn't (back then) see a practical way of lowering the pivot point, let alone a low level drive. Now that is achieved I can revisit the etches and get an up to date revised one sorted.
Back to the Roco/Atlas GP9 project, think I'm just about there now, several minor changes along the way, mostly inverse compensation so that when printed it's all square and straight.
A quick reminder/comparison from where we started to where I am now.
On the left the original high level drive line gear tower, on the right the new low drive line gear tower. One of the recent alterations was to the front and rear ends, I removed the horns that hold the side frames in place and replaced it with the depressed transom beam, I still need to shape the side frame blobs on the end to loom a bit more like a Blomberg but I won't expend a lot of energy there, just enough to appease the eye a little more.
The next change was some new wheels from Roxey Mouldings.
The original sits outside with it's super wide treads, to be fair the replacements are not accurate, I think P48 is 0.115" scale thickness, these are 0.140" and the originals are 0.200". Still, they're good enough for OW5 and I can turn them to much closer to scale but keep the same gauge; a growing trend loosely called PW5 or more accurately P48 wheels at OW5 gauge.
The cover plate is just laid on top, the new fixing holes in each corner have not been drilled yet, the original Roco/Atlas uses self tappers and they tend to spit the resin where the thread starts, not parallel with the bore but on the surface where it blows out a little circular pancake of resin. The new fixings are countersunk 10BA screws and a nut (probably in a shaped recess) on top of the block.
Internally you need to turn the axles down from 5/16" to 4.00 mm to accept the plastic gear (revised design ones to reduce splitting should be done in a few days), then you need to turn a shoulder each side down to 3.50 mm to accept the Roco/Atlas square brass bearing.
Assembled low drive line power brick, the UJ has one side (outer) at a lightly larger diameter, it's fine whilst the drive is straight but if you kick it up then the fingers around the ball just catch the top of the block so I'll add a small recess in there on the final version, I'll also put recesses for the nuts that the side plate cover screws fix into.
Temporarily fitted into the Red Caboose GP9 chassis.
The primary reason for all the effort, chopped nose GP9's and free cab floors.
Clearance with all the recent modifications is ample, in fact the chassis has slipped down a bit in the last shot so there is more than shown. The chopped nose etched cab was kind of put on hold as I couldn't (back then) see a practical way of lowering the pivot point, let alone a low level drive. Now that is achieved I can revisit the etches and get an up to date revised one sorted.
richard carr
Western Thunderer
Mick
Isn't it possible to reuse the original axle with a replacement gear ?
Looks really good, S7 JB will be so pleased he hasn't built his yet
Richard
Isn't it possible to reuse the original axle with a replacement gear ?
Looks really good, S7 JB will be so pleased he hasn't built his yet
Richard
Yorkshire Dave
Western Thunderer
The light grey colour of your shed reminds me of something,I wonder what it is ?
Ah yes, I know - what it needs is the bottom half painting a darker grey and a silver grey or yellow stripe between the two, that would do it !
I'd just paint the end scarlet, add some scarlet wings on the side and letter it COTTON BELT
. The shed will weather itself.
mickoo
Western Thunderer
AppreciatedDog's doodahs. What will you do about the brake bits on the side frames? (I think I can guess)
Not sure yet, two options, modify the block present to give a tapered look to mimic the outside, second, remove the block altogether and add something to the arms on the motor block to represent that area.
The first option is a passing nod to what is a basic shape and never going to be accurate, the second is the next level of detail but still accepts it's never going to be perfect due to other trade offs on the truck side frames for production.
I'd like to do the second option because that's about as far as you can go with the existing side frames, the only down side is that those extra 'sticky out bits' might be too fragile and snap off. Not that you'll be taking the side off an on very often I suppose.
The correct solution is new side frames (discussed earlier and planned long term) in which case is there any point doing anything with the current side frames and adding bits to the power block....which will then need removing when the new side frames get done.
mickoo
Western Thunderer
Richard,
That's a point I hadn't actually considered, so went back and checked.
The downside is that the replacement wheels are threaded at one end and screw onto the axle, you'd need to add that thread to the Roco/Atlas axle.
The other wheel with the insulated bush fits perfectly on the Roco/Atlas shaft.
If you could broken an arrangement with Roxey (or Peartree who I think are the source of these diesel wheels) for a bag of wheels with insulated hubs then they would be a direct swap.
If you wanted to alter the wheels for P48 then they'd need trimming down correspondingly and you'd only need to find a new gear to suit in the UK.
mickoo
Western Thunderer
Just a little update, the revised axle gears were done and test fitted, these shouldn't split now.
I turned the bearing shoulders a little too much on this axle so it has excess side play, but even then the gear clears the inner walls....just.
I may just bevel the outer edge a bit, a belt and braces exercise to make absolutely sure the gear does not touch the Roco/Atlas floor plate recess.
I turned the bearing shoulders a little too much on this axle so it has excess side play, but even then the gear clears the inner walls....just.
I may just bevel the outer edge a bit, a belt and braces exercise to make absolutely sure the gear does not touch the Roco/Atlas floor plate recess.
mickoo
Western Thunderer
Cheers, hadn't thought of it like that, it's an over engineered solution to a simple problem, the original gear has very thin shoulders so there is little strength there to prevent it splitting, therefore, if you increase the material in that area then you reduce the chance of it splitting.
I perhaps went overboard with the size increase, I suspect 60% larger would have sufficed so that some of the tooth is proud of the shoulder, rather than flush. The Mk II is a little more pleasing to the eye.
richard carr
Western Thunderer
Mick
That's a great idea with the gear, I have a set of wheels that would benefit from those.
Richard
That's a great idea with the gear, I have a set of wheels that would benefit from those.
Richard
Let there be Carnage 
Big Train James
Western Thunderer
I've been meaning to get onboard with this discussion for a while now, all sorts of thoughts swirling around in my head regarding modifying the trucks and drives on these units. I've been distracted though, so I'm very late to the game. Herewith, some delinquent ideas, since you're already essentially done 
. While recognizing that you aren't trying to totally reinvent the wheel for this particular application, I also see that you are actually reinventing a fair amount. So hopefully I'm not too out of line.
Firstly, just in a general way, I think you can draw some inspiration from the Atlas mp15dc Blomberg trucks, which are designed to fit under the cab floor. They share the same basic design premise as the Roco/Atlas trucks, meaning shaft to worm, worm to worm gear, idlers to axle gears. The big difference is in the size, number, and arrangement of gears within the box, and those gears affect both the form factor of the gearbox but also its height.
The Roco truck uses quite large gears, for the worm gear but especially for the idler gears. It also uses a single idler to each axle, versus two smaller idler gears per axle on the Atlas mp gearbox. The result is a long, boxy enclosure for the Roco design, versus a reduced profile for the newer Atlas design. Also, by reducing the diameter of the worm gear, the height of the drive shaft and worm can be lowered relative to the axle centerline. It all adds up to a lower, smaller gearbox.
I presume you are trying to reuse the existing Roco gears, but you have also produced a new axle gear. It's not all that difficult to lay out the revised gear train in cad, and it's also fairly simple to generate 3d gear models from online sources that can be imported into cad for manipulation and printing. One interesting thing to note, is that the new Atlas gearbox has a compound gear for the worm gear, with a helical cut worm gear mated with a spur gear to mesh with the idlers. It would be a trick to machine such a custom gear, or to find a stock version available. But it's a relatively simple task to mate the two together in cad and 3d print the result. For point of reference, the axle and idler gears for the new Atlas gearbox measure at 11.89mm overall diameter, the pitch diameter would be a touch less than that. I don't have the worm gear diameter, as I would need to disassemble a truck to get that. It can be done if necessary.
If nothing else, the revised gearbox profile would accomplish the added clearance for the universal joint cups.
Next topic, the motor mount. I touched on this previously, but have done more thinking on the topic since. I really think the motor mount needs to be adjusted to lower the motor in the frame, and I don't think it would be all that difficult to achieve with a 3d printed bracket. The goal would be to drop the motor the same amount as the driveshaft, so something like 15mm.
A hole would need to be cut in the frame so the mounting bracket could drop down through the floor. A new bracket would need to be drawn and printed, with mounting flanges positioned just below the motor centerline. I got out the crayons again. The bracket would sit down in the hole in the frame, resting on the mounting flanges at either end.
I've been tinkering with a Red Caboose frame and walkway, and it looks like the motor would remain hidden behind the fishbelly portion of the frame, even lowering it by 15mm. The top of the fuel tank would need modification to clear the motor, but the air reservoirs could be left as stock.
Lowering the motor simplifies the drive train, but more importantly it opens up the volume of the long hood for placement of the electronics and the use of a larger speaker.
The speaker is the last point. Many of us have discovered the Tang Band speaker modules, there are two, the 1931S and the 1815S, that would provide nice sound but are just barely too large to fit flat in most plastic diesel bodies. Both modules have the same dimensional and performance specs, the difference is that the 1931S features a convex driver cone while the 1815S features a concave cone.
I've had a lot of discussions about the Tang Band speakers with Bob Sobol from the forum associated with the Appalachian & Ohio O scale layout out in Colorado. One thing we discussed was the possibility of modifying the TB speaker enclosures to get them to fit in O scale locomotive shells. My purpose was for my sw1500 kitbash, but the A&O crew loves the Red Caboose gp9 models.
Bob cut apart a non-functioning 1931S module, which revealed that the wall thickness was something on the order of .075" to .080". I had previously worked on a module using a Dremel hand tool, the result of which was effective but very crude. I just recently collaborated with another modeler here to machine the speaker enclosure instead, and the results are very satisfactory. We removed .045" from both sides of the speaker, without breaching the enclosure wall, and also removed the mounting tabs from the ends. The result is a speaker that fits cleanly inside the Red Caboose shell, without modification to the shell, and without causing any bowing or other effect on the hood sides.
The point of putting this speaker info here, is to support the idea of lowering the motor. Also it's food for thought of course. The same speaker mod allows for the fit of the TB modules in other Atlas locos like gp60's or gp35's. My opinion is that being able to maximize the sound quality, by allowing the use of a more capable speaker, makes the motor repositioning worthwhile.
I'll drop the speaker information into the Red Caboose specific thread as well. Happy to provide specs and methodology on the machine work if others are interested.
. While recognizing that you aren't trying to totally reinvent the wheel for this particular application, I also see that you are actually reinventing a fair amount. So hopefully I'm not too out of line.Firstly, just in a general way, I think you can draw some inspiration from the Atlas mp15dc Blomberg trucks, which are designed to fit under the cab floor. They share the same basic design premise as the Roco/Atlas trucks, meaning shaft to worm, worm to worm gear, idlers to axle gears. The big difference is in the size, number, and arrangement of gears within the box, and those gears affect both the form factor of the gearbox but also its height.
The Roco truck uses quite large gears, for the worm gear but especially for the idler gears. It also uses a single idler to each axle, versus two smaller idler gears per axle on the Atlas mp gearbox. The result is a long, boxy enclosure for the Roco design, versus a reduced profile for the newer Atlas design. Also, by reducing the diameter of the worm gear, the height of the drive shaft and worm can be lowered relative to the axle centerline. It all adds up to a lower, smaller gearbox.
I presume you are trying to reuse the existing Roco gears, but you have also produced a new axle gear. It's not all that difficult to lay out the revised gear train in cad, and it's also fairly simple to generate 3d gear models from online sources that can be imported into cad for manipulation and printing. One interesting thing to note, is that the new Atlas gearbox has a compound gear for the worm gear, with a helical cut worm gear mated with a spur gear to mesh with the idlers. It would be a trick to machine such a custom gear, or to find a stock version available. But it's a relatively simple task to mate the two together in cad and 3d print the result. For point of reference, the axle and idler gears for the new Atlas gearbox measure at 11.89mm overall diameter, the pitch diameter would be a touch less than that. I don't have the worm gear diameter, as I would need to disassemble a truck to get that. It can be done if necessary.
If nothing else, the revised gearbox profile would accomplish the added clearance for the universal joint cups.
Next topic, the motor mount. I touched on this previously, but have done more thinking on the topic since. I really think the motor mount needs to be adjusted to lower the motor in the frame, and I don't think it would be all that difficult to achieve with a 3d printed bracket. The goal would be to drop the motor the same amount as the driveshaft, so something like 15mm.
A hole would need to be cut in the frame so the mounting bracket could drop down through the floor. A new bracket would need to be drawn and printed, with mounting flanges positioned just below the motor centerline. I got out the crayons again. The bracket would sit down in the hole in the frame, resting on the mounting flanges at either end.
I've been tinkering with a Red Caboose frame and walkway, and it looks like the motor would remain hidden behind the fishbelly portion of the frame, even lowering it by 15mm. The top of the fuel tank would need modification to clear the motor, but the air reservoirs could be left as stock.
Lowering the motor simplifies the drive train, but more importantly it opens up the volume of the long hood for placement of the electronics and the use of a larger speaker.
The speaker is the last point. Many of us have discovered the Tang Band speaker modules, there are two, the 1931S and the 1815S, that would provide nice sound but are just barely too large to fit flat in most plastic diesel bodies. Both modules have the same dimensional and performance specs, the difference is that the 1931S features a convex driver cone while the 1815S features a concave cone.
I've had a lot of discussions about the Tang Band speakers with Bob Sobol from the forum associated with the Appalachian & Ohio O scale layout out in Colorado. One thing we discussed was the possibility of modifying the TB speaker enclosures to get them to fit in O scale locomotive shells. My purpose was for my sw1500 kitbash, but the A&O crew loves the Red Caboose gp9 models.
Bob cut apart a non-functioning 1931S module, which revealed that the wall thickness was something on the order of .075" to .080". I had previously worked on a module using a Dremel hand tool, the result of which was effective but very crude. I just recently collaborated with another modeler here to machine the speaker enclosure instead, and the results are very satisfactory. We removed .045" from both sides of the speaker, without breaching the enclosure wall, and also removed the mounting tabs from the ends. The result is a speaker that fits cleanly inside the Red Caboose shell, without modification to the shell, and without causing any bowing or other effect on the hood sides.
The point of putting this speaker info here, is to support the idea of lowering the motor. Also it's food for thought of course. The same speaker mod allows for the fit of the TB modules in other Atlas locos like gp60's or gp35's. My opinion is that being able to maximize the sound quality, by allowing the use of a more capable speaker, makes the motor repositioning worthwhile.
I'll drop the speaker information into the Red Caboose specific thread as well. Happy to provide specs and methodology on the machine work if others are interested.
Last edited:
Kylestrome
Active Member
Here's another vote in favour of Tang Band speakers. They are basically the same speakers that DC Kits sell as so-called "Earthmovers" and provide a surprising amount of bass. I use the smaller 2008S version in my British 4mm diesels.
David
David
mickoo
Western Thunderer
This I'll come back to in due courseI've been meaning to get onboard with this discussion for a while now, all sorts of thoughts swirling around in my head regarding modifying the trucks and drives on these units. I've been distracted though, so I'm very late to the game. Herewith, some delinquent ideas, since you're already essentially done
Firstly, just in a general way, I think you can draw some inspiration from the Atlas mp15dc Blomberg trucks, which are designed to fit under the cab floor. They share the same basic design premise as the Roco/Atlas trucks, meaning shaft to worm, worm to worm gear, idlers to axle gears. The big difference is in the size, number, and arrangement of gears within the box, and those gears affect both the form factor of the gearbox but also its height.
The Roco truck uses quite large gears, for the worm gear but especially for the idler gears. It also uses a single idler to each axle, versus two smaller idler gears per axle on the Atlas mp gearbox. The result is a long, boxy enclosure for the Roco design, versus a reduced profile for the newer Atlas design. Also, by reducing the diameter of the worm gear, the height of the drive shaft and worm can be lowered relative to the axle centerline. It all adds up to a lower, smaller gearbox.
View attachment 162654View attachment 162655View attachment 162656
I presume you are trying to reuse the existing Roco gears, but you have also produced a new axle gear. It's not all that difficult to lay out the revised gear train in cad, and it's also fairly simple to generate 3d gear models from online sources that can be imported into cad for manipulation and printing. One interesting thing to note, is that the new Atlas gearbox has a compound gear for the worm gear, with a helical cut worm gear mated with a spur gear to mesh with the idlers. It would be a trick to machine such a custom gear, or to find a stock version available. But it's a relatively simple task to mate the two together in cad and 3d print the result. For point of reference, the axle and idler gears for the new Atlas gearbox measure at 11.89mm overall diameter, the pitch diameter would be a touch less than that. I don't have the worm gear diameter, as I would need to disassemble a truck to get that. It can be done if necessary.
If nothing else, the revised gearbox profile would accomplish the added clearance for the universal joint cups.
Next topic, the motor mount. I touched on this previously, but have done more thinking on the topic since. I really think the motor mount needs to be adjusted to lower the motor in the frame, and I don't think it would be all that difficult to achieve with a 3d printed bracket. The goal would be to drop the motor the same amount as the driveshaft, so something like 15mm.
A hole would need to be cut in the frame so the mounting bracket could drop down through the floor. A new bracket would need to be drawn and printed, with mounting flanges positioned just below the motor centerline. I got out the crayons again. The bracket would sit down in the hole in the frame, resting on the mounting flanges at either end.
View attachment 162657
I've been tinkering with a Red Caboose frame and walkway, and it looks like the motor would remain hidden behind the fishbelly portion of the frame, even lowering it by 15mm. The top of the fuel tank would need modification to clear the motor, but the air reservoirs could be left as stock.
Lowering the motor simplifies the drive train, but more importantly it opens up the volume of the long hood for placement of the electronics and the use of a larger speaker.
The speaker is the last point. Many of us have discovered the Tang Band speaker modules, there are two, the 1931S and the 1815S, that would provide nice sound but are just barely too large to fit flat in most plastic diesel bodies. Both modules have the same dimensional and performance specs, the difference is that the 1931S features a convex driver cone while the 1815S features a concave cone.
I've had a lot of discussions about the Tang Band speakers with Bob Sobol from the forum associated with the Appalachian & Ohio O scale layout out in Colorado. One thing we discussed was the possibility of modifying the TB speaker enclosures to get them to fit in O scale locomotive shells. My purpose was for my sw1500 kitbash, but the A&O crew loves the Red Caboose gp9 models.
Bob cut apart a non-functioning 1931S module, which revealed that the wall thickness was something on the order of .075" to .080". I had previously worked on a module using a Dremel hand tool, the result of which was effective but very crude. I just recently collaborated with another modeler here to machine the speaker enclosure instead, and the results are very satisfactory. We removed .045" from both sides of the speaker, without breaching the enclosure wall, and also removed the mounting tabs from the ends. The result is a speaker that fits cleanly inside the Red Caboose shell, without modification to the shell, and without causing any bowing or other effect on the hood sides.
View attachment 162663View attachment 162664View attachment 162665
The point of putting this speaker info here, is to support the idea of lowering the motor. Also it's food for thought of course. The same speaker mod allows for the fit of the TB modules in other Atlas locos like gp60's or gp35's. My opinion is that being able to maximize the sound quality, by allowing the use of a more capable speaker, makes the motor repositioning worthwhile.
I'll drop the speaker information into the Red Caboose specific thread as well. Happy to provide specs and methodology on the machine work if others are interested.
mickoo
Western Thunderer
Back to the overseas anorak, the new etched GP9 test chassis turned up this week.
One or two mistakes, not overly concerned as I knew quite a few other bits would need tweaking once it became a 3D object in your hand. The drag boxes are not complete or the bracing behind the pilot plate.
Originally the chassis was going to be for rear truck drive only with the Roco/Atlas truck and motor mount, the front truck was going to be a simple chopped down dummy truck. Whilst the etches were away being processed the front truck evolved rapidly into a low drive unit previewed the other day.
The down side is that the chassis has one tall truck mount and one small, I'm unsure going forward as to make the chassis dual purpose, I.E. supply two small brackets for those that might want a low floor option and two tall brackets for those that just want to replace the flimsy plastic chassis in the Red Caboose kit with the minimal amount of work.
The motor mount is depressed between the frame rails but does not go below the cill flange, currently it's a simple concave 3D block with a rib at each end to stop the motor moving back and forth. It's quite agricultural but robust and as a consequence raises the motor drive a couple of mm higher than the truck, I've heard dead straight drive shafts through UJ's isn't optimum, no idea how true that is.
The internal walls above the frames add rigidity and on the next version will have securing brackets to hold a cover plate, that'll encase the top of the motor with another former to stop it bouncing around, it'll also act as a solid base plate for the biggest Tangband speaker I can cram in there. One thing you do have to do with the new internal walls is to trim a little off the plastic footplate, about 1 mm each side where the internal wall widens around the motor, it's not a problem as it's overly thick here anyway and the plastic hood unit has ample space to fit over the widened section.
Currently the footplate height is just a fraction over height, it's the same height as the original chassis which from my doodlings is about 1 mm too high. This leaves a bigger gap between the lower cill flange and truck sides than I'd ideally like. Lowering by 1 mm does mean the front truck securing nut is just going to encroach into the cab floor area so I need to get creative with the fixing and packing plates/resin truck print. I may have to change the idler gear to a 24T or 23T to drop the first one and thus worm a fraction lower.
Having done all that the final part will be to find a way to secure the fuel tank and air reservoirs and make a platform/shelf over the rear (low drive line) truck pivot to hold the DCC gubbins. Then it'll be adding all the detail parts, clips, holes in frames for pipework etc.
Once I've cleaned all this up and settled on a final design i'll package a synopsis up and post it in the Red Caboose thread, just don't wan tot dilute that with all my ramblings as I bounce around design changes and probably numerous small updates.
One or two mistakes, not overly concerned as I knew quite a few other bits would need tweaking once it became a 3D object in your hand. The drag boxes are not complete or the bracing behind the pilot plate.
Originally the chassis was going to be for rear truck drive only with the Roco/Atlas truck and motor mount, the front truck was going to be a simple chopped down dummy truck. Whilst the etches were away being processed the front truck evolved rapidly into a low drive unit previewed the other day.
The down side is that the chassis has one tall truck mount and one small, I'm unsure going forward as to make the chassis dual purpose, I.E. supply two small brackets for those that might want a low floor option and two tall brackets for those that just want to replace the flimsy plastic chassis in the Red Caboose kit with the minimal amount of work.
The motor mount is depressed between the frame rails but does not go below the cill flange, currently it's a simple concave 3D block with a rib at each end to stop the motor moving back and forth. It's quite agricultural but robust and as a consequence raises the motor drive a couple of mm higher than the truck, I've heard dead straight drive shafts through UJ's isn't optimum, no idea how true that is.
The internal walls above the frames add rigidity and on the next version will have securing brackets to hold a cover plate, that'll encase the top of the motor with another former to stop it bouncing around, it'll also act as a solid base plate for the biggest Tangband speaker I can cram in there. One thing you do have to do with the new internal walls is to trim a little off the plastic footplate, about 1 mm each side where the internal wall widens around the motor, it's not a problem as it's overly thick here anyway and the plastic hood unit has ample space to fit over the widened section.
Currently the footplate height is just a fraction over height, it's the same height as the original chassis which from my doodlings is about 1 mm too high. This leaves a bigger gap between the lower cill flange and truck sides than I'd ideally like. Lowering by 1 mm does mean the front truck securing nut is just going to encroach into the cab floor area so I need to get creative with the fixing and packing plates/resin truck print. I may have to change the idler gear to a 24T or 23T to drop the first one and thus worm a fraction lower.
Having done all that the final part will be to find a way to secure the fuel tank and air reservoirs and make a platform/shelf over the rear (low drive line) truck pivot to hold the DCC gubbins. Then it'll be adding all the detail parts, clips, holes in frames for pipework etc.
Once I've cleaned all this up and settled on a final design i'll package a synopsis up and post it in the Red Caboose thread, just don't wan tot dilute that with all my ramblings as I bounce around design changes and probably numerous small updates.
richard carr
Western Thunderer
That's really nice Mick, when can I order one ?
The cover plate for the motor is a great idea too.
Richard
The cover plate for the motor is a great idea too.
Richard
mickoo
Western Thunderer
Once I'm happy it all fits and is good to go.
Mk II is now with the etchers, hopefully back by Monday or Tuesday, it only has the truck mounts for the low drive units, I might do a Mk II that has the high level mounts for a direct swap with the Roco/Atlas (R/A) trucks. I'm going to make the towers removable so you could start with the high level ones and then go over to the low level later if you wanted and not have to unsolder it all.
I've found a commercial source for nylon idler gears, R/A use mod 0.7 gears......that took some finding out and I needed a 24T idler for that diameter, not 25T as I had originally, I've done some test ones with 24T and it feels smoother.
The only downside with the nylon ones, or most commercial ones I've seen to date, is the width, the teeth are 6 mm wide, the truck is set up for R/A which is 4 mm wide teeth and 5 mm hubs, the hubs on the commercial ones are 15 mm but offset all to one side.
They're not expensive but each one would need the boss turned off and the width reduced to fit the 3D truck.....the search continues.
Going back a few posts, yes you can reuse the R/A axles with Roxey diesel wheels, the insulated one isn't a tight direct fit on the R/A axle, it slides on easily so you'd need some loctite to hold it long term, the screwed one needs boring (4.8 mm) out to take the R/A insulated bush, then that is a tight fit on the R/A axle. I suppose you could bore both wheels out to 4.8 mm and recover both insulated bushes off the R/A axles.
The Roxey wheels are 3'-1" (1:43.5 scale) and a little tight on the brake blocks, ideally they need to be 3'-0" which scales out closer to the 1:48 40" wheel, I might try and turn these to get a fraction more clearance.
JasonD
Western Thunderer
I'm 75. That's my current excuse for not getting new stuff done in Nth American O. But young O-scalers are swamped with 'useful' technologies to extend their working day to override hobby time: mobile pho... oh, can't be bothered to finish these 3 pages, but let me admit that with the wobble in NWSL wheel supply and the cost of USPS having to fund their pension scheme, I've spoken to Peartree about getting wheelsets produced here.
They're OK to do it and I have some Ow5 and P48 tooling they can evaluate. Minimum quantity of 100 wheelsets was agreed a while ago, my hesitation is how I will face handling surpluses. Then the good parrot says that's only 25 3-rail frt cars to convert" And, predictably, the bad parrot says 33"s or 36"s, what axle ends? Yes, locos trickier, but gears on US China-built locos use Imperial shafts - 4.8mm=3/16" which is what Peartree normally produce.
Yes, parts and as-new/downsizing tables at the Winchester Meet on Saturday 22/10/22.
Jason
They're OK to do it and I have some Ow5 and P48 tooling they can evaluate. Minimum quantity of 100 wheelsets was agreed a while ago, my hesitation is how I will face handling surpluses. Then the good parrot says that's only 25 3-rail frt cars to convert" And, predictably, the bad parrot says 33"s or 36"s, what axle ends? Yes, locos trickier, but gears on US China-built locos use Imperial shafts - 4.8mm=3/16" which is what Peartree normally produce.
Yes, parts and as-new/downsizing tables at the Winchester Meet on Saturday 22/10/22.
Jason