7mm Steph's modern traction workbench

Steph Dale

Steph Dale

Western Thunderer
mickoo said:
Steph,

Those look very nice, how much smaller in dia are the 14xx and 16xx motors, would a 14xx motor be almost fully under floor? The 14xx might suit shunty plank layouts but I suspect you'd need the bigger 18xx for longer trains etc.

Kindest
Click to expand...

The 14xx is 16mm*14mm in section. Oriented in the gearbox as I expect it to fit it'd be very nearly under-floor. I'm actually considering this for a Steve Beattie 10800 kit I've got here, although an 1824 will still fit well. The 16xx are 16mm in dia.

To be honest it's all a question of what power is needed. For a 'Type 1' loco having the overall power of a couple of watts (i.e. Mashima 1833 territory) can be achieved with two small motors (like 1426 or 1824). And this would go all the way up to a type 5 (like this 'ere Class 60) where something around 5W is adequate and can be provided by two Mashima 1833s; one in each bogie.

So yes, the Canon 1833s are out for this loco. For a start I won't be using enough of their power or speed range in a loco which can only do 60mph and secondly I realised a week or so ago that they have flats in their shafts, which makes them pretty useless for press-fit worm gears. It's solvable, but not something I'd expect everyone to do.

A new order will go through to Branchlines later this evening or tomorrow to provide a pair of Mashima 1833s for this loco and full set of transmission components for the other Class 60. Whoops; cat, bag, out of...

Steph
 
Steph Dale

Steph Dale

Western Thunderer
With gearboxes well on their way, my thoughts turned back to the loco. Recognising I need a couple of demonstration pieces before I build the Class 60 (which will have sprung bogies), this evening I've started assembling the basic bogies of my Class 47.

I'll sling up a couple of piccies later in the week, but I'm pleased how few changes have needed to be made to the basic MMP parts to get the 'boxes in. It'll need a few more tweak to get the split axle pick-up installed, but it's a start.

I'll have to order the wheels tomorrow...

Steph
 
Steph Dale

Steph Dale

Western Thunderer
Guys,

Piccies as promised!

There a couple of small mods required to allow the new gearboxes to fit. Thankfully nothing major as these pictures show. The top picture is at the end with the motor attached, the lower is the end with the 'free' gearbox:
IMG_1512v1.jpg
IMG_1513v1.jpg

The 'free' end will gain a strap/spacer very shortly to make up for the loss of material. Nothing major, just a short length of 3mm strip. This picture shows why it's needed, there's not a lot there to stop the bogie spreading, should it decide to do so!
IMG_1515v1.jpg

And here's how they looked this afternoon. At this point I'd started fitting bearings and playing with the compensation parts. So the pickup arrangements have been finalised; the bogies use a mixture of split axles and 'American'. In reality that means the bogies are built up and insulated from the body as 'American' pick up, but the side which would normally not be doing a lot has bearings insulated from the bogie frame, giving 12-wheel pick up, once the split axles are considered. You may just be able to make out the copper-clad patch used to insulate the bearing from the frame in the photo.
I've also decided to modify the compensation beams slightly. I wasn't hugely happy about the beams resting on a 3/32" rod without a sleeve, so I've sleeved the beams and sideframe holes with 3/32" tube; they'll take a 1/16" rod, which remains entirely adequate. The increased area of the tube/sleeve will reduce wear over the life of the model though, so it's worth the effort I feel:
IMG_1520v1.jpg

So that's where I am now. The gearboxes etches are due from the suppliers late next week and the other items required to make them up as full packs will follow in due course. Hopefully I'll have these bogies ready for show and tell, with their drive installed, by York show...

Steph
 
Steph Dale

Steph Dale

Western Thunderer
It's amazing how time flies. Two weeks after my posting above and we're mission accomplished; with a bogie complete and the second one ready for final assembly. So to catch up, here's what happened:

Firstly the pickup arrangements have been finalised, which require me to insulate all the bearings from one side of each bogie, which is done using double-sided copper clad paxolin. In the beam the bearings are replaced with Albion Alloys brass tubing, this shot showing clearly the insulation gap provided by the copper-clad. The tube is concentric in the holes by the way; its position has been guaranteed by using the next (telescopic) size of tube as a spacer:
IMG_1525.JPG

The bearing in the frame is dealt with similarly - in this case the copper clad patches the hole in the frame and then has a countersink applied until the insulation shows through. The bearing is then soldered in. This all helps preserve the chassis original alignment, which means that the rest of the assembly should be pretty straightforward:
IMG_1526.JPG

The insulation gaps shown above are then filled with epoxy to give some strength and also to stop any conductive crud bridging what are otherwise very small insulation breaks.

That done, the gearboxes were made up and installed. I stopped for a (self-) congratulatory photo session:
IMG_1547.JPG

From underneath you can see the Branchlines universal joint coupling the motor to the second gearbox, some of the insulation breaks in the axles can be made out too. The bit of (0.7mm) brass wire heading up from the gearbox is a simple torque reaction arm to stop the gearbox rotating around the axle:
IMG_1550.JPG

I'm very pleased at this point. From now on it's back to following the build instructions after this short off-piste adventure. Next challenge is getting underframe photos of my chosen loco (47 306 'The Sapper').

Steph
 
mickoo

mickoo

Western Thunderer
47 306, quick look on the web and looks like its one with the water tank removed so identical to a walk around I did on 370.
IMG_2875.jpg

IMG_2863.jpg

IMG_2871.jpg

IMG_2872.jpg

I have more if you think they are of use?

Note the MMP 47 kit does not replicate the dropped engine room floor or longitudinal girders correctly. I had the same issue with the 57 and decided to rebuild the whole floor section to replicate the dropped fish belly section under the engine, the photos above should help you work it out but if you need more info just shout and I'll help where possible. It also does not replicate the front underfloor drag box correctly as well, seem to recall that the triangular side members that run under the cab windows were at the wrong angles and didn't line up with the real loco, again I can dig my 57 out and photo to show what's required.

Addendum, quick scribble of what's required, red is all new, green is new or extensions, on the tank mount left I found it easier to make it all new rather than extend.
IMG_2875a.jpg
 
Steph Dale

Steph Dale

Western Thunderer
Hehehe, yes please Mick!

The problem (which you've so simply solved) is that I don't know what I'm looking for with Class 47 underframes. In describing it as 'water tank removed' I know I'll shortly have half an idea which paragraphs of the instructions I should be following! :rolleyes:

Really some way outside my knowledge these diesel things... :D

Steph
 
mickoo

mickoo

Western Thunderer
Steph, ok will post up on the morrow, must get some Zzzz's big day tomorrow, 125% traverser overload deflection tests, about 210T to load up in lay mans terms LOL.

But just quickly, there are four battery boxes under the loco, between and each side in a rough H pattern in plan view are the water tanks, two water tanks actually, the outer ends nearest the bogies also have a smaller tank which is lub oil. Fuel tanks are within the body shell.

These under frame tanks changed quite a lot over the locos history, initially all water tanks were removed and you were left with four battery boxes and two small lub tanks almost hanging in free space, then the freight only locos /3 series had old water tanks converted into extra long range fuel tanks, it also increased their weight back upto somewhere near the original weight which increased adhesion, pretty handy as they were all mostly on heavy trains, stone, MGR, Freightliner, tanks etc. I need to dig my notes out as to exactly what tank was what and when sort of thing but that's a rough guide. I do believe some locos even had both water tanks added back as really long range fuel tanks, some 57s had only one, others had two and I have a dim recollection that there may even be two or three types of tank design or certainly on the 57 modified tanks that were halves welded together, I.E the tanks are not symmetrical so the modified would be two left hands welded together or something, again need to dig my notes out.

Most, if not all class 57 carried over their under gear from the 47's they previously were, so in that respect are almost identical to a late variant 47, but I have enough photos of 47 to help you along I think.

But first you need to get your under floor right which requires some scratch building, unless of course you wish to have a flat floor and just follow the kit right out of the box.
 
Ressaldar

Ressaldar

Western Thunderer
Hi Steph,

very neat work.

Could the design be adapted to suit a 'self contained' 8'6" DMU bogie or would you mount the motor on the chassis and just have the gearboxes in the bogies? Please excuse my rambling if you have already covered this type of application, I'll stand outside the classroom while I read the earlier posts - again:headbang:

cheers

Mike
 
S

SteveO

Guest
Brilliantly simple, love the look of this. Is the middle axle sprung? Does it interfere with the prop shaft?
 
adrian

adrian

Flying Squad
I don't think it's sprung and correct me if I'm wrong but I think the middle axle is compensated with the axle with the remote gearbox.
 
mickoo

mickoo

Western Thunderer
adrian said:
I don't think it's sprung and correct me if I'm wrong but I think the middle axle is compensated with the axle with the remote gearbox.
Click to expand...
Affirmative, standard out of the box MMP 3 axle bogie layout, inner axle fixed, intermediate and outer on a compensation beam.
 
Steph Dale

Steph Dale

Western Thunderer
Mick,
I'll have to check through the parts and instructions to decide how I'm going to handle the underframe so don't think I'm up to a decision point just yet. However, now I'm aware they may be an issue it likely to mean that I'll make any necessary changes! Thanks for the Dropbox link - I'll investigate further this evening...

Ian,
Many thanks!

Mike,
Either suit; there are links to an Application Note and Planning Sheet on my most recent posting in the SDMP thread.

Steve,
I see you've already had your main question answered by Adrian and Mick. The compensation beams can just about be made out in my last picture; the pivot rod is very clear as it crosses the chassis between the two lower axles. The prop shaft misses the middle axle by about 5mm, so no interference at all.

Steph
 
Steph Dale

Steph Dale

Western Thunderer
Dog Star said:
Tidy, the clearance between the cardan shaft of the ABC diesel motor bogie and the pivot bolt on the JLTRT Cl.37 is almost 10thou... on a good day.
Click to expand...

Graham,
In this version I've got about 4mm clearance for a screw head between the prop shaft and the hole in the bogie frame, which is plenty. In addition I have the advantage that the Branchlines universal joint components can clip in/out of an otherwise-assembled bogie. so assembly drill would be something like this:
1. Take complete bogie and clip out prop shaft
2. Screw bogie to loco frame
3. Clip in prop shaft.

Well, it would do; but I've already decided to fit working secondary suspension...

Steph
 
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