East Barnet Joint Stock - a workbench

[chris p bacon]

2 hours ago, 2750Papyrus said:

I'm not quite ready to post a photo yet but can confirm that I have enjoyed the build

 

I'd love to see it too when you're ready, (any feedback on the etched bogies is welcome) 

[Chas Levin]

8 hours ago, 2750Papyrus said:

Thanks for your detailed reply on lining. 

 

Yes, the 12 wheeler is one of those featured on the LNER forum.  I'm not quite ready to post a photo yet but can confirm that I have enjoyed the build, even if it has been time consuming.  My eyes will only focus close-up for about 20 minutes and I seem to have "clumsy" days when it is best to put the model aside!  

 

May I suggest you drop Graeme a pm to check availability?  

Thanks, I will.

Yes, I think most of us have good and bad days when eyesight and dexterity are a little below par. I too put the project aside and use the time to catch up on other stuff that I've been putting off in favour of modelling - I find that makes me less disappointed that I couldn't do any modelling, because then it feels like I've cleared some time for when my eyes and hands are on better form.

Glad to know you've enjoyed the build I would love to see some photos when it's ready.

[Chas Levin]

Today, I made and installed my first compensation beam:

 

Leaving the beam uncut whilst bending the business end to shape and soldering it in place was a trick picked up from Iain Rice's "Locomotive chassis in 4mm" book - I like to think I should have thought of it myself but had I not done so, the process would have been far less easy.

I'd been hesitating for a few days to take the plunge; in spite of having read a great deal about how compensation beams work and reached the point of being able to visualise the principle of the mechanism in my mind, I was still a little nervous of getting it to work. (I put the time to good use though, adding an extra stretcher for a guide spring on the rear radial truck,  making a pickup PCB and soldering a nut in to mount it - I araldited the pickup PCB on my last loco but the ability to take the PCB off in the event of pickup problems seems a useful idea).

In the event however, it was just as easy as lots of people - including Mr Rice of course - say it is. In fact I think its very simplicity invites doubt in the first-time builder as to whether it can really work: how wrong I was!

But it was only by making one and actually seeing it work, playing with it and seeing the wheels move in connection with each other, that I realised just how clever a piece of design it really is! A bit like riding a bike: you can read about it - and watch film of it - until your eyelids droop, but it only really makes sense when you climb on and have a go...

And it certainly is simple - when the beam's cut down to size and viewed in the stripped down chassis there's no disguising it as anything more than a metal rod, but it works like magic:

 

I found myself marvelling at it with every movement of the driving axle and bogie, wondering how I could have thought it would be difficult! Actually Mike Sharman comments in the introduction to his 'Flexichas' book that the system itself is a little like religious faith, in that once you believe in it the technical part is quite easy, but the difficult part is getting you to believe. I read those words and moved on without giving them too much thought, but he was spot on. Here's a closer view of it back in the full assembly, where you can see it running between the front driven axle and the bogie:

 

At the moment the front end of the beam is just resting on the middle of the rear part of the central bogie stretched, but I will probably add a rubbing plate, possibly a forked arrangement to distribute the beam's downward force a little further forward and a little nearer the sides of the bogie. I also built the bogie with a small equalisng beam of its own, currently set at an angle such that it doesn't touch the rear bogie axle; if the bogie doesn't ride well enough, I'll elongate the bogie's rear axle holes and bend the beam down to contact the axle so that it rocks - you can just see the beam emerging from the rear-facing vertical face of the bogie stretcher, underneath the main compensating beam itself. I'll also add a guide spring for the bogie if needed, which I'll try and fit from the front.

Still can't get over how well the beam arrangement works and how clever it is...

 

Edited May 9, 2022 by Chas Levin

[Chas Levin]

Today I dealt with two small and time-consuming but important jobs. First, a centralising guide spring for the radial truck, soldered to the small additional frame spacer added for the purpose, to fit through the loop on top of the truck; and second, two side springs with looped ends, soldered to the inside of the frames for downward tacking force:

 

 

 

 

The side springs will need some further bending after test running - they'll probably exert too much downward force where they are at present.

Then, turning to the front end of the main compensation beam: I was not at all happy with it resting only on the rear part of the central bogie stretcher, as there would be far less downward force on the front bogie axle. It can't rest centrally as that space is occupied by the transverse slot for the bogie pivot bolt that comes down, through the slot, from the underside of the footplate. So... I decided to make an addition to the end of the beam that would have a central hole for the pivot bolt to pass through and an extended beam end in front of the pivot bolt that would sit on the front end of the bogie stretcher.

I started off with the leftover part of a wagon W-iron (cut I think from the Falcon GNR Fish Van kit a while back):

 

 

This was then scored and the side areas bent up - the transverse footprint needs to be as narrow as possible in order to avoid restricting bogie side movement as little as possible:

 

 

This piece was then soldered onto the end of the compensation beam, and a small piece of the same beam material (1.6mm nickel silver rod) added to the front end 'pocket', to give a suitable surface to make contact with the top of the stretcher:

 

 

I then wrapped round the joint between the beam and it's new brass end with tinned copper wire and flowed it with solder, for long-term strength, rather than relying purely on the initial soldered joint:

 

 

This end piece now fits over the bogie pivot bolt, moving freely up and down as part of the beam, with two points of contact, one behind and one in front of the pivot bolt that goes down through the stretcher:

 

 

 

 

Clearances all seem fine so far. That last picture above is taken holding the chassis at an angle, allowing the bogie to drop down unsupported: in its normal position there's only a small gap between main and bogie frames and the newly added assembly is barely visible, even before the inevitable matt black paint. I'll double-check tomorrow to make sure nothing's catching where it shouldn't when running through a variety of points and curves.

Following some more cleaning up of the added beam end piece, the next thing is to add a centralising guide spring for the bogie. I'm intending to put this at the front of the bogie, partly because there's too much else going on at the rear and partly as recommended in Iain Rice's book, to impart guiding force to the body as early into curves as possible.

[Chas Levin]

The last few days' modelling time has been spent on bogie tracking:

 

Having added a centre guide spring wire to the front of the bogie, hooking the end under a bracket just behind the buffer beam on the underside of the footplate, while it worked beautifully 90% of the time, at one section of my layout (a difficult one at the best of times, a curve going through left followed by right hand points followed by a diamond crossing!) I was  faced with the exact opposite of what should occur: instead of the bogie guiding the body into the curves, the body imparted sufficient sideways force to the bogie to cause the front wheels to derail about half the time.

However, it's actually been a notorious derailing blackspot for years, usually escaping notice because of unguided bogies, so I shall finally deal with it (by adding a shim to a check rail - non-prototypical but effective), thereby not only helping the C12 but everything else that runs over it.

 

Whilst running these tests, I also became aware of another problem. The LRM radial truck etch has a small fold-up tab with a hole for the centre guide spring, an nice piece of design but the tab leaves its shape as a cut-out in the upper surface of the truck, the surface that moves to and fro under my two end-coiled downward-bearing tracking springs - you can see below in the photo the two wear lines on the truck's top surface where the springs bear, each one going right to the edge of that central gap:

 

This is sometimes a problem because every so often the truck moves sufficiently far to one side that one of the coiled spring ends drops down into that centre gap - holding the chassis and moving the truck from side to side you can see the bounce and hear the telltale click. The spring ends bounce out readily enough but it was quite clearly not the smooth action that was wanted and it needed a new top surface for the truck, all one piece, cut from scrap etch:

 

The two little tabs on the new brass cover plate are to guard against the possibility of the springs dropping off either end of the truck too; from what I can tell this isn't actually happening at the moment, but according to Murphy's Law, had I not included those, it would have started to happen the moment everything was back together. Here it is soldered to the truck and filed to shape:

 

And finally, with the wheels back in and the spring bearing surface cleaned up:

 

And I'm happy to report that it works perfectly and has entirely eliminated the problem, giving a smooth movement to either side extreme with no clicks or catches. Just to be clear, no criticism is intended of the LRM etch (which is a very neat, simple and excellent product), as I suspect it isn't intended to be used with springs of the type I'm using, so this issue probably doesn't usually occur...

Edited May 9, 2022 by Chas Levin

[Chas Levin]

Happy New Year to all!

 

After a relaxing Xmas break - and some time spent on other projects - it's time to get back to the C12 - today, the LRM motor mount was made up, the Mashima motor added and test run, the pickup PCB made and installed, pickups bent to shape and tested:

Though the picture above shows the pickups (0.3mm PB wire) before being bent to shape and sheathed in PTFE.

The pickup PCB is wired to the motor and the motor, mount and pickups are desigend to be removable as one assembly (a bit of a wiggle but fine with axles out) for removal after all testing, for adding brake rigging, painting and so forth.

 

I'm still going at the moment with plain Romford/Markits crankpins but I'm considering using the DeLuxe ones with threaded retainers, as I like the idea of being able to remove the rods in case of damage or the need for adjustment or modification. However, the DeLuxe ones I have are ones where the 14BA thread on the actual protruding pin (that takes the threaded rod retaining bush) doesn't go right down to the collar that sits on the wheel face, which means the bushes don't screw right down to the collar.

 

I found a thread on RM Web from July last year that illustrates this issue: (

) The original poster counterbored the inner ends of the bushes to allow them to screw all the way down, but others mentioned in reply having pins with threads right the way to the ends of the pins and the official Markits catalogue shows the pins as threaded for their whole length, so I'm left a little puzzled.

 

As a first step, I've ordered some more from a different supplier to see whether I perhaps just have old stock; if they turn up the same I'll give Mark at Markits a call once we're past the first grey days of January to see if he can shed any light - perhaps I'm missing something. I tried screwing one of the bushes firmly but gently fully home and it did go, but didn't feel like it was happy and I wonder whether it might have stripped the thread from the initial mm or so inside the bush, or splayed the end slightly and whether it might affect long-term stability.

 

Has anyone else come across this issue and if so, what solutions can you suggest please?

 

The rods for the C12 have large enough ends to accommodate the necessary 1.6mm holes, by the way - I checked .

Edited May 9, 2022 by Chas Levin

[Chas Levin]

Pickups done and tested, rods on and chassis running fairly smoothly as an 0-4-0, though a little tweaking still needed and it's rather more noisy than expected:

 

The motor mount doesn't allow much adjustment of mesh but I'll have a look, as I'm sure it should run a little more quietly...

Edited May 9, 2022 by Chas Levin

[Chas Levin]

A quick update on the DeLuxe crankpins question: I spoke to Mark at Markits and he confirmed that the small unthreaded length at the base of the 14BA outer pin section is a limitation of how close the die cutting nut can go to the collar, and that counter-boring the threaded bush to allow it to go over that last little bit is the best fix - so your method using a piece of 20SWG wire is an excellent trick, Richard!

I also received the other stock I'd ordered and they too exhibit a small unthreaded section at their base, though it's slightly smaller on most of them than the ones I already had.

I'll tackle the counter-boring in due course, but not for this kit, as crankpin clearance under the footplate has proved to be a bit of a problem using standard pins with flat washers anyway, so I'm not going to make things worse by trying to accommodate threaded bushes. I've had to resort to removing semi-circular areas where the pins come up to the footplate, which will be invisible with side tanks and boiler in place - they'll be seen in photos in due course.

Meanwhile, my confidence as regards the drive system turned out to be a little misplaced, due entirely to my lack of experience in these things: a salutary tale for the novice loco builder follows...

When I bought this kit, quite a while ago, I hadn't built any loco kits (and not that many other kits at all) and I was nervous of the whole process of working out which motor and mount would work well, so I also bought the motor mount that John at LRM recommended - one of LRM's own - and thought no more about it.

I hadn't at that time considered which axle I'd drive - or any other construction details - and when I began on the kit, I got very involved in learning about suspension systems and plumped eventually for compensation, specifically a beam between the front driven axle and the bogie, because of the perceived running advantages (and I must say it does run beautifully).

Unfortunately, it didn't occur to me at that point to check that the motor mount I had could also be used on the rear driven axle... which it can't, because of clearance with the cab! I must stress here, this is entirely my fault - no criticism of LRM intended at all!

Actually though, it has worked out rather well and the job of finding another mounting method has proved an exciting challenge, and makes it much more interesting. Looking round at other choices, the High Level range - with their almost infinitely variable options - seemed a good possibility, especially when I remembered that I had a RoadRunner+ in stock, bought for use with another LRM kit... and lo and behold, I think it will work:

 

It's a little difficult to see in this picture, but I've laid the unfolded etches of the two parts of the RoadRunner+ in place, with an axle going through the axle hole of the lower articulated piece and the main upper part laid where it will intersect and I think it will work - if not, I'll try using a Drivestretcher, though I don't think that will be necessary...

Edited May 9, 2022 by Chas Levin

[Jol Wilkinson]

Chas,

 

I use the "underslung" position for the motor whenever possible, but it relies on having a motor that will fit between the frames. The LRM mounts are good for this and the once readily available range range of Mashima motors meant that this could be done in any 4mm scale gauge. Unfortunately, since the demise of Mashima motors, I'm not aware of a range of motors that can match the sizes and performance that the Mashimas provided.

 

The attached photos will show the "underslung" concept in locos with quite different driving wheel sizes. I found it useful because it left some room in the firebox for ballast and also get the drive under the cab floor.

 

LNWR Precursor

 

LNWR Coal Tank

 

 

 

Edited January 13, 2021 by Jol Wilkinson
Additional text

[Chas Levin]

9 hours ago, Jol Wilkinson said:

Chas,

 

I use the "underslung" position for the motor whenever possible, but it relies on having a motor that will fit between the frames. The LRM mounts are good for this and the once readily available range range of Mashima motors meant that this could be done in any 4mm scale gauge. Unfortunately, since the demise of Mashima motors, I'm not aware of a range of motors that can match the sizes and performance that the Mashimas provided.

 

The attached photos will show the "underslung" concept in locos with quite different driving wheel sizes. I found it useful because it left some room in the firebox for ballast and also get the drive under the cab floor.

 

LNWR Precursor

 

LNWR Coal Tank

 

 

 

Thanks Jol - I'm using a Mashima motor in fact, a 1024, but the positioning you've used there isn't quite possible as things are, because there's quite a long frame stretcher in between the two driver pairs and it would necessitate removal of pretty much the whole thing. It locates into the frames by tabs and slots so it couldn't be removed simply by melting solder and would have to be cut out using a piercing saw. That might affect chassis stability and while I could make and fit another stretcher or two, it seems a lot of trouble to go to if the HL box will fit.

The ashpan sides also come up the insides of the frames to meet the underside of that stretcher, so although the motor fits between the frames themselves, the tops of the ashpan sides might cause a problem, given the low angle at which the motor would have to sit.

I think I'm going to have to nibble away a little of the rear part of that stretcher even to use the HL box - I'll make it up and see how things look. Another possible option would be to angle up the last few mm of the front of the cab floor to give some extra space, but I'll need to check whether that would be visible and what else that might affect.

I'm also hoping that the HL drive system might be quieter, as I've still not been able to get the LRM gearing to be much less noisy. I'm puzzled by this - I'm sure it's something I'm doing incorrectly (it's the first motor mount I've made) but I've checked and re-checked everything I can think of: the squareness of the folds (they're dead square); the bearings give a smooth, square but absolutely free-running axle; it runs quietly out of the chassis but with the axle plus wheels in place and being driven (in other words, with the wheels just revolving in mid-air) but once in the chassis and driving the whole assembly, it's quite a lot noisier. The axle still freewheels smoothly going through both frames and motor mount sides, so that's not an issue.

I've been running the chassis - mainly to test the compensation arrangements - using the LRM mount (as shown in my last posted photos of it) with no superstructure in place, but with footplate, rear truck and bogie, so the main part of the job (a smoothly running chassis) is going very well. Pickup is only on the four drivers and has been excellent, which I put down in part to the compensation keeping the wheels in better contact with the rails

 

Edited January 14, 2021 by Chas Levin

[Jol Wilkinson]

I find it best work out the motor position before assembling the frames, leaving out/moving/modifying any conflicting spacer before I fit it. LRM and HL both have a website download with their motor mount outlines, etc.

 

I haven't found the LRM gears especially noisy (they are CNC cut by another manufacturer who also sell direct) and have only one unfinished loco with HL gears  which isn't quite finished so can't yet compare. I have found that it isn't unusual for the brass/steel gears to be noisier in one direction than another, but that may be down to some vibration caused in the motor when the shaft is pushed back against the bearings in the opposite direction.

[Chas Levin]

4 hours ago, Jol Wilkinson said:

I find it best work out the motor position before assembling the frames, leaving out/moving/modifying any conflicting spacer before I fit it. LRM and HL both have a website download with their motor mount outlines, etc.

 

I haven't found the LRM gears especially noisy (they are CNC cut by another manufacturer who also sell direct) and have only one unfinished loco with HL gears  which isn't quite finished so can't yet compare. I have found that it isn't unusual for the brass/steel gears to be noisier in one direction than another, but that may be down to some vibration caused in the motor when the shaft is pushed back against the bearings in the opposite direction.

Thanks Jol and yes, amongst the lessons being learned on this build is the early prioritising of the motor position. I'm afraid I got so excited by the whole suspension / compensation subject that everything else took a bit of a back seat while I tried to understand that side of things and I rather rushed the chassis in order to try out the beam system!

No problem though - one way or another I'll get the power where it needs to go, especially now I know the chassis runs properly.

As to the noise question, my instinct so far (based partly on observation of this unit and partly on considering where this type of noise could be being generated) is that it's mainly down to the worm/gear mesh so I shall look at adjusting that again, but if I end up using the HL gears I'll put this LRM set aside and try it again in the next suitable loco.

[Chas Levin]

So, the High Level Kits RoadRunner+ looks like it'll fit perfectly, tucking under the front end of the cab floor, but to be sure I'll need to assemble and try installing it. In response to a request on Tony Wright's 'Wright writes' thread during a discussion about HL gearboxes for someone to post detailed photos of a build, I thought I'd put up some pictures I took today while assembling my first HL gearbox, which went together very easily and runs beautifully.

So, here's what you start with, after removing parts from the etch and cleaning up where necessary:

 

 

Three sizes of hole need carefully broaching out to be a snug fit - six for 2mm steel rod for gear shafts, two for the piece of 1mm wire that holds the sides of the main unit at the correct distance and the two for 1/8" axle bushes:

 

 

 

 

The etch for the lower articulated drive carriage section is then folded up and tested for free running with the axle (including a little gentle work with an 1/8" reamer, which I used in preference to a tapered cutting broach to avoid tapering the bushes):

 

 

I then test fitted the lower section to the driven axle (after filing down the outsides of the bushes to fit between the axle bushes already installed in the frames) and it already fits under the front of the cab floor (hooray), though when the upper section of the box is added the whole assembly will need to lean forward and downwards to accommodate, necessitating removal of some of the rear of the central frame spacer, visible in the photo below, immediately in front of the gearbox piece:

 

 

 

I then folded up the main gearbox body and used the very handy little remote attachment piece provided in the kit to check the spacing of the two sides, before soldering in a piece of 1mm wire to keep that spacing, and running solder fillets along both folds of both pieces - in the photo below, they're being held together for a test fitting by a piece of wooden cocktail stick:

 

 

And, at last, we have a gearbox that fits, driving the rear axle, underneath the cab floor (and in this photo by the way, you can also see where I had to remove some material from the footplate to accommodate the upper movement arc of the crankpins, which I think was necessitated because the crank throw on these Markits wheels is a little longer than prototype, something I need to check against the drawings later):

 

 

It required filing back the rear edge of that central frame spacer by about 3mm but the spacer was about 15mm long to start with so that doesn't cause a problem and the pick-up PCB - which bolts to the spacer's underside - is sufficiently short and held sufficiently low down that it isn't affected either.

The next job is to cut the steel rod for the gear shafts, which I did using a seriously hefty pair of pliers with sharp cutting edges, wrapped in a rag to catch the two pieces as they fly apart, filing the cut ends afterwards. They're cut about 1/2mm longer then the box width, to allow easier retaining of the ends by glueing when the time comes:

 

 

Here are all the parts - aside from the motor and axle - laid out as they'll be installed: the worm gear, stage 1 gear and brass spacer, idler and idler washer, final drive gear and shim:

 

 

Assembly can be a bit fiddly and I used various ideas including threading a screwdriver through one side, through a gear and washer and then pushing it back out with the gear shaft:

 

With both shafts and the stage 1 and idler gears installed and held in place for testing by some masking tape, the axle goes in with the final drive gear on it, to be secured by a grub screw (which because of the slim gears is quite centrally located and can make use of a Markits slotted axle):

 

And we then have the complete gearbox, only lacking the motor:

 

Adding the motor (a Mashima 1024), we have a very smooth, very quiet little unit: marvellous:

 

Everything was pretty straightforward; I went slowly and carefully - first one I've built - and the only slightly unnerving part was putting the worm on the motor shaft. It's intended to be a tight friction fit and the instructions caution against using excessive force if the fit's too tight, because of the risk of damage to the shaft or the motor, advising careful use of a broach to enlarge the hole and the use of retaining compound or superglue if necessary afterwards. I found it's a bit of a balancing act to get the fit loose enough to get it on without upsetting the motor, keeping it tight enough for a good grip whilst at the same time using some Loctite 601 retaining compound - which means you have to get it right first time because it won't be coming off again any time soon!

All in all though, I can only echo what others have said - lovely piece of design and engineering, works beautifully, very pleasing!

Edited May 9, 2022 by Chas Levin

[Bucoops]

1 hour ago, Chas Levin said:

So, the High Level Kits RoadRunner+ looks like it'll fit perfectly, tucking under the front end of the cab floor, but to be sure I'll need to assemble and try installing it. In response to a request on Tony Wright's 'Wright Writes' thread during a discussion about HL gearboxes for someone to post detailed photos of a build, I thought I'd put up some pictures I took today while assembling my first HL gearbox, which went together very easily and runs beautifully.

So, here's what you start with, after removing parts from the etch and cleaning up where necessary:

 

Three sizes of hole need carefully broaching out to be a snug fit - six for 2mm steel rod for gear shafts, two for the piece of 1mm wire that holds the sides of the main unit at the correct distance and the two for 1/8" axle bushes:

 

The etch for the lower articulated drive carriage section is then folded up and tested for free running with the axle (including a little gentle work with an 1/8" reamer, which I used in preference to a tapered cutting broach to avoid tapering the bushes):

 

I then test fitted the lower section to the driven axle (after filing down the outsides of the bushes to fit between the axle bushes already installed in the frames) and it already fits under the front of the cab floor (hooray), though when the upper section of the box is added the whole assembly will need to lean forward and downwards to accommodate, necessitating removal of some of the rear of the central frame spacer, visible in the photo below, immediately in front of the gearbox piece:

 

I then folded up the main gearbox body and used the very handy little remote attachment piece provided in the kit to check the spacing of the two sides, before soldering in a piece of 1mm wire to keep that spacing, and running solder fillets along both folds of both pieces - in the photo below, they're being held together for a test fitting by a piece of wooden cocktail stick:

 

And, at last, we have a gearbox that fits, driving the rear axle, underneath the cab floor (and in this photo by the way, you can also see where I had to remove some material from the footplate to accommodate the upper movement arc of the crankpins, which I think was necessitated because the crank throw on these Markits wheels is a little longer than prototype, something I need to check against the drawings later):

 

It required filing back the rear edge of that central frame spacer by about 3mm but the spacer was about 15mm long to start with so that doesn't cause a problem and the pick-up PCB - which bolts to the spacer's underside - is sufficiently short and held sufficiently low down that it isn't affected either.

The next job is to cut the steel rod for the gear shafts, which I did using a seriously hefty pair of pliers with sharp cutting edges, wrapped in a rag to catch the two pieces as they fly apart, filing the cut ends afterwards. They're cut about 1/2mm longer then the box width, to allow easier retaining of the ends by glueing when the time comes:

 

Here are all the parts - aside from the motor and axle - laid out as they'll be installed: the worm gear, stage 1 gear and brass spacer, idler and idler washer, final drive gear and shim:

 

 

Assembly can be a bit fiddly and I used various ideas including threading a screwdriver through one side, through a gear and washer and then pushing it back out with the gear shaft:

 

With both shafts and the stage 1 and idler gears installed and held in place for testing by some masking tape, the axle goes in with the final drive gear on it, to be secured by a grub screw (which because of the slim gears is quite centrally located and can make use of a Markits slotted axle):

 

And we then have the complete gearbox, only lacking the motor:

 

Adding the motor (a Mashima 1024), we have a very smooth, very quiet little unit: marvellous:

 

Everything was pretty straightforward; I went slowly and carefully - first one I've built - and the only slightly unnerving part was putting the worm on the motor shaft. It's intended to be a tight friction fit and the instructions caution against using excessive force if the fit's too tight, because of the risk of damage to the shaft or the motor, advising careful use of a broach to enlarge the hole and the use of retaining compound or superglue if necessary afterwards. I found it's a bit of a balancing act to get the fit loose enough to get it on without upsetting the motor, keeping it tight enough for a good grip whilst at the same time using some Loctite 601 retaining compound - which means you have to get it right first time because it won't be coming off again any time soon!

All in all though, I can only echo what others have said - lovely piece of design and engineering, works beautifully, very pleasing!

 

 

Ah so I'm not the only one who cuts that steel shaft with pliers. I got told to do it with a cutting wheel instead, but that just makes a mess.

[Jon4470]

15 hours ago, Bucoops said:

 

 

Ah so I'm not the only one who cuts that steel shaft with pliers. I got told to do it with a cutting wheel instead, but that just makes a mess.

I tried using Xuron cutters once for cutting the steel shafts.......now have a lovely notch in them

 

I have resorted to using a piercing saw.

[Bucoops]

15 minutes ago, Jon4470 said:

I tried using Xuron cutters once for cutting the steel shafts.......now have a lovely notch in them

 

I have resorted to using a piercing saw.

 

Not surprised - Xuron are great for precision cutting, it needs something a bit more robust for cutting hardened steel (or piano wire is another use for the pliers I use). 

 

This kind of beastie https://www.toolstation.com/ck-redline-vde-combicutter/p91918 although I've had mine donkeys years.

[Chas Levin]

Actually I had intended to try using a cutting disc (bought some a while back and still haven't used them) but I thought I'd give the pliers a quick try first, as High Level very helpfully provide considerably more length of steel rod that will be needed for one gearbox, thereby allowing for experimentation. The cutters I used are not quite like the ones you posted the link for Rich, they are actually more like 'normal' pliers, i.e. with a grip as the main section and a secondary cutting section further back, more like this : https://www.amazon.co.uk/Chrome-Vanadium-Combination-Pliers-yellow/dp/B01JE4Q77W.

I mark to the edge of the section to be removed with red marker pen, then grip the rod gently but firmly at that point in the cutter jaws; I then wrap an old tea-towel loosely round rod and end of the pliers, get down on my knees on the floor and put one side of the piers on the floor (uncarpeted), so I can then lean with considerable weight on the other side of the pliers, pressing down against the floor. The tea-towel - or similar wrapping - is an absolute safety necessity, as the bang of the jaws closing sends the two pieces flying apart with enough force to punch holes in opposite walls of the room!

 

Edited January 17, 2021 by Chas Levin

[Bucoops]

that's why I prefer the shearing method - the bits just drop out rather than behave like an exocet

[Chas Levin]

Just now, Bucoops said:

that's why I prefer the shearing method - the bits just drop out rather than behave like an exocet

Actually, it's quite exciting... I really do need to get out more

[Chas Levin]

So, here we have the LRM C12, version 2:

 

The High Level RoadRunner+ runs beautifully; the gear shafts are glued in place and the articulated section is also glued in place, which I did by 'tack gluing' it with a tiny spot of cyano while it was still in the chassis in order to get the exact angle between it and the main gearbox, before removing it and gluing it properly. I'd have preferred soldering but removing it from the chassis and dismantling the gears without losing the exact angle struck me as too risky - a degree here or there can't easily be spared, given the small clearances involvded...

You'll also see in the above picture that instead of reasonably long pieces of wire sheathing to hold the rods on the pins, I cut slim 'washers' from the wire material, the same thickness as the Markits crankpin washers: this was because of the clearance issues with the footplate, so I could trim the crankpins early on to what will be their final length.

I made up the pickups, their PCB and motor as one assembly, as mentioned earlier up the thread - it's quite convenient to have got all the electrical soldering out of the way and it lifts out of the chassis very easily:

Edited May 9, 2022 by Chas Levin

[Chas Levin]

Last October I posted the results of some comparions of different manufacturers' 4mm loco suspension systems, as I was learning about them and interested to see how different systems worked, what features they had and what parts might be interchangeable. Since then, I've aquired three more brands - Blacksmiths, Puffers and Exactoscale - so I thought I'd post an updated version of the chart:

 

And here's the original Excel file too, in case it's of use:

 

Hornblock comparison 20210121.xlsx

 

The Blacksmith Models ones are interesting because they differ from all the others I've seen, in that the inside surfaces of the hornguides are as deep as the bushes, with a central groove in them, and the bushes are very thin, with a flared ridge round their outside which fits into the guides' grooves - the reverse of the normal arrangement where the thin edge of the guide engages a groove in the side of the bushes.

 

The Exactoscale ones are more puzzling and didn't come with instructions - I have yet to figure out how they work:

Edited May 9, 2022 by Chas Levin

[Jol Wilkinson]

Chas,

 

from memory, the etched plates are soldered onto the "flange" on the bearing. The hole in the top of the guide has to be tapped to take the hollow grub screw. The guide is then soldered to the inside of the frames (or possibly into the frame hornguide cut-out).

The bearings are held in place by the etched plate against the back of the wheel and from falling out by wire through one of the pairs of lower holes.

Springs were supplied (possibly in separate packs of different spring rates) that fitted into the hollow grub screws and the flat pins fitted into those to bear against the top of the bearing. The grub screws can be wound up and down to set the ride height

 

I bought some but didn't like the concept. The bearings  ride on the grub screw and only moves down when a drop in the track is encountered. 

 

I hope that helps.

[Chas Levin]

8 hours ago, Jol Wilkinson said:

Chas,

 

from memory, the etched plates are soldered onto the "flange" on the bearing. The hole in the top of the guide has to be tapped to take the hollow grub screw. The guide is then soldered to the inside of the frames (or possibly into the frame hornguide cut-out).

The bearings are held in place by the etched plate against the back of the wheel and from falling out by wire through one of the pairs of lower holes.

Springs were supplied (possibly in separate packs of different spring rates) that fitted into the hollow grub screws and the flat pins fitted into those to bear against the top of the bearing. The grub screws can be wound up and down to set the ride height

 

I bought some but didn't like the concept. The bearings  ride on the grub screw and only moves down when a drop in the track is encountered. 

 

I hope that helps.

Thanks Jol, yes, that certainly helps.

Supplying springs of different strengths seems a very good idea (I've wondered before now why more manufacturers of sprung systems didn't / don't offer that), but from what I've learnt so far about sprung systems I too would prefer the idea of movement being possible for both hills and dales.

 

Unless... would it be the case that where a rise in the track lifts the front righthand wheel of an 0-6-0, the front lefthand, the middle and the rearmost righthand wheels effectively drop, because the chassis - at the top of the rise - is temporarily on an upward angled straight line drawn between the front righthand and rearmost lefthand wheels?

I hope I've explained that well enough: I'm picturing the track, either side of where it rises under one particular wheel, in effect 'dropping away' from under the other wheels, because it dips back to the correct height, so wheels which can spring downwards will move down to follow it.

If that's a valid case, that would allow this system to work - perhaps that's what Exactoscale had in mind?

[Chas Levin]

On 17/01/2021 at 15:43, Jon4470 said:

I tried using Xuron cutters once for cutting the steel shafts.......now have a lovely notch in them

 

I have resorted to using a piercing saw.

Jon, I meant to ask: how do you get the first notch going, to start the cut, without the blade slipping around? I tried my piercing saw on another piece of rod as an experiment last night but the springiness of the blade (even when tightened as fully as possible) contributed to the tendency to slide around on the extremely smooth metal surface and I had the greatest difficulty!

 

I also last night tried for the first time cutting a motor shaft - I discovered that the redundant shaft end needs to come off on the C12 Mashima to allow clearance into the boiler void - and finally tried a carborundum cutting disc. This works much better - even though the motor shaft steel is harder than the gear shaft stuff - because the speed of the drill (only a Bosch 9.6v re-chargeable that goes to 980 RPM) and the cutting edge combine to start the first locating groove very quickly. That being said, the edge of the disc was visibly smooth and shiny after only a couple of minutes and clearly not making as much headway, so as the discs were very cheap I put another unused one on to finish the job.

 

Not a particularly enjoyable job either, what between maintaining a strong enough grip with needle-nosed pliers close enough to the motor body to allow a decent amount of the shaft to be removed, whilst not unduly straining the shaft or the motor's innards; judging how often to stop so as to avoid excessive heat, as against getting the job done reasonably quickly to minimise stress on the mechanism; holding the pliers sufficiently firmly against the bench to try to minimise possible excessive vibration; keeping the drill and disc at the right angle - I wouldn't have been so concerned if Mashima were still making the blinking things!

Still, another lesson for me in what should be done at the very earliest stages of planning a loco build, in terms of assessing the work necessary to accommodate the motor and gearbox, as this job would have been considerably easier on a bare motor, without soldered leads and a worm in place...

 

I always tell myself there's nothing wrong with making mistakes, as long as I learn from them. I've slept soundly many a night after doing something really, really stupid, just be telling myself that: I highly recommend it!

[Jol Wilkinson]

3 hours ago, Chas Levin said:

Thanks Jol, yes, that certainly helps.

Supplying springs of different strengths seems a very good idea (I've wondered before now why more manufacturers of sprung systems didn't / don't offer that), but from what I've learnt so far about sprung systems I too would prefer the idea of movement being possible for both hills and dales.

 

Unless... would it be the case that where a rise in the track lifts the front righthand wheel of an 0-6-0, the front lefthand, the middle and the rearmost righthand wheels effectively drop, because the chassis - at the top of the rise - is temporarily on an upward angled straight line drawn between the front righthand and rearmost lefthand wheels?

I hope I've explained that well enough: I'm picturing the track, either side of where it rises under one particular wheel, in effect 'dropping away' from under the other wheels, because it dips back to the correct height, so wheels which can spring downwards will move down to follow it.

If that's a valid case, that would allow this system to work - perhaps that's what Exactoscale had in mind?

Chas,

 

I should have added that the centre axle(s) are set so that the bearings can rise when the outer axles are "bottomed out". That provides flexibility in the system to deal with track variation. Provided the track is built to a good standard, this should work as there shouldn't be much more than +/- variation over the loco wheelbase.

Coil springs have never really worked in 4mm, getting consistent miniature springs, calculating axle loads, etc. being difficult. CSBs address this better and wire springs  from music wire has proved better. However, despite the claims for CSBs I have stuck with compensation which is simpler to set up.

 

2 hours ago, Chas Levin said:

Jon, I meant to ask: how do you get the first notch going, to start the cut, without the blade slipping around? I tried my piercing saw on another piece of rod as an experiment last night but the springiness of the blade (even when tightened as fully as possible) contributed to the tendency to slide around on the extremely smooth metal surface and I had the greatest difficulty!

 

I also last night tried for the first time cutting a motor shaft - I discovered that the redundant shaft end needs to come off on the C12 Mashima to allow clearance into the boiler void - and finally tried a carborundum cutting disc. This works much better - even though the motor shaft steel is harder than the gear shaft stuff - because the speed of the drill (only a Bosch 9.6v re-chargeable that goes to 980 RPM) and the cutting edge combine to start the first locating groove very quickly. That being said, the edge of the disc was visibly smooth and shiny after only a couple of minutes and clearly not making as much headway, so as the discs were very cheap I put another unused one on to finish the job.

 

Not a particularly enjoyable job either, what between maintaining a strong enough grip with needle-nosed pliers close enough to the motor body to allow a decent amount of the shaft to be removed, whilst not unduly straining the shaft or the motor's innards; judging how often to stop so as to avoid excessive heat, as against getting the job done reasonably quickly to minimise stress on the mechanism; holding the pliers sufficiently firmly against the bench to try to minimise possible excessive vibration; keeping the drill and disc at the right angle - I wouldn't have been so concerned if Mashima were still making the blinking things!

Still, another lesson for me in what should be done at the very earliest stages of planning a loco build, in terms of assessing the work necessary to accommodate the motor and gearbox, as this job would have been considerably easier on a bare motor, without soldered leads and a worm in place...

 

I always tell myself there's nothing wrong with making mistakes, as long as I learn from them. I've slept soundly many a night after doing something really, really stupid, just be telling myself that: I highly recommend it!

 

I have shortened Mashima motor shafts be wrapping the motor in masking tape, leaving just the shafts sticking out (to keep rubbish out of the motor and bearings). I then put the required end shaft in a micro drill, spin it up and use a good quality triangular needle file to "machine" a groove in the unwanted shaft. I take my time with this and don't apply too much pressure. When about 70% - 80% in and through the outer case hardening, the shaft can be broken off. Brush rubbish off and remove the masking tape. I've done that on about fifteen motors without problems.

Edited January 22, 2021 by Jol Wilkinson
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