Heavy Duty Frame construction

This page demonstrates a step by step workshop on how the construct a new frame for an existing body, in this case the V36 diesel shunter. The V36 is the german War Department shunter developed somewhere around 1936. After the war these machines were found widespread all over Europe and upto Egypt, 4 of these saw service in Belgium, 1 at the NMBS, 2 in industry and 1 in an army depot. The V36 is an 0-6-0 with idler, 360 hp motor and high and low gearing regime for shunting and line work. Many machines were later used in industry but were also used by the DB. The DB did order several new series with improvements. The model brought by Minitrix is a bit curious mix, basically with a long wheelbase of the improved series but not accurate. The long end of the cab is not standard although one known photo exists with this sidepanel arrangement. The majority had 3 louvre doors on each side combined with the old version of the grill on the nose. The model seems to come in 3 versions: 1) limping around, 2) not too bad 3) very smooth. The latter version is rare. The problem is due to bad or virtually no quartering on axles with gears, knurled axles and coupling rods. Due to the knurled axle ends there is not much what can be done to improve on the running quality of the model as we cannot simply rotate the wheels for decent quartering.

Here we describe how to turn this product into a model of the standard V36 such as the NMBS type 230 shunter or industry shunters CCB 216/217. The task contains building a new split frame with a 10mm Faulhaber, 7 mm wheels of the 2mm SA sitting in the right place and we put in a DCC decoder. Further we improve on some of the gross deviations in the cab. Shorten footplate such that the cab is in plane with the buffer beam, replace the old grill, add the missing louvre doors and put on a new coat.

V36 in Belgian livery

The final result in new livery



The new frame is a massive splitframe of general design such as I have developed earlier for a similar diesel namely the V60, but also adaptable to a large range of other NMBS shunters all having 8 mm wheels but the same wheelbase and set-up. The motor sits on top of the frame with a 10 mm flywheel. This is the maximum size as the hood is not wider. The gearing is dependent on the available gearwheels. The model described makes use of the original Minitrix gearwheels donated by one of the old types of model but opened out to muff size. These have 15 t and are M 0.4 (64DP), this the maximum size that can be used in view of rail clearance. Note that the association doesn't have 15 teeth only 14 or 16. The current production models have a M 0.3 gear train and a much better motor but still need better wheels. The worm and wormwheel arrangement are 40 teeth M 0.2 in combination with 10 teeth M 0.4. This gives a 60 : 1 reduction. An idler between 9-12 teeth M0.4 is necessary to bridge the gap between the wormwheel combination and gears on the wheels. The insulation is by 0.1 mm PS sheet on both sides of the frame, thus the brass section will be fully insulated

drawing with dimensions
drawing available as PDF

This drawing shows the theoretical dimensions we need for the new chassis. Dimensions for different idler gears are in the notes.


Phase 1: Starting out is preparing a package for drilling. This concerns 3 strips of 2mm thick brass from the local DIY market, 2 of these are soldered together. Note if you don't have a milling machine there are smarter combinations that offer less work further on, notably a package of 1+2+2+1 is recommended then. The frame plates are 0.5 mm PB. The package is kept temporarily together for drilling using double sided tape. We first drill 1.4 mm through the whole package at both ends. Next step is removing the frame plates and open out the holes in the brass package to 3 mm. Please note that these are dimensions are for FS160, the tolerance I use between wheels and frames is considerable less compared to 2mm scale ending up with about the same width of frame, still the track is 0.42 mm narrower.


The package of brass and phosporbronze sheets on top of some basic prototype information.


Here we see the main parts of the entire kit. To right the drilled raw chassis which has now 3mm Tufnol rods mounted in the brass which are tapped for M 1.4 screws. The frame plates have countersunk holes for centering the frames with the screws. Further we see the motor with mounted worm, wormwheel and gearwheels. Three muffs, fitting screws, the flywheel and the wheels. Missing are the set of gearwheels for the muffs. The notepad below it shows the type of calculation necessary for arriving at the right gears that also fit the available space. Sorry to disappoint those who think building locos is black art, Pythagoras would have done it with his eyes closed. In general these calculations are the only advance steps I do, I never make any further drawings as I don't need them. The accompanying frame drawing in this article was made afterwards. Cab dimensions are read from G.A.'s or suitable drawings of different source.

collection of parts

All parts for the gearing.


The next step is putting the frame together using the screws and flattening the base so we have an edge to set out the dimensions. We drill the necessary holes 1.5 mm for fitting the wheels and the idler gear. Without a mill first start by filing smooth with a large hand smooth file (say 25cm long by 2.5 cm width), then go over to draw filing to create a flat base and then finish and clean up on wet and dry nr 240.

flattening the base

flattening the base for setting out dimensions and drill holes.


Disassembling the package again for opening out the holes in the inner frame for the muffs. First open out the 1.5mm holes and drill to 3.5 mm, then using piercing saw and file or mill to 4 mm square slots.

clearing for muffs

Making slots for the muffs.


Here we have a look on how I adapted the original brass M 0.4 gears for the muffs. The original axles are 2.2 mm thus the gears are first mounted on a centered 2.2 mm pin using solder, then we drill a new 3.2 hole and cut-off it from the spigot again. This stage is shown above. Of course association gears with 3.2 mm muff holes can be used as well to skip this stage.

adapting gears for 3.2 mm muffs

making muff holes in the gears.


Producing the space for the gears in the center. I did this by milling. However a milling machine is not necessary if you adapt the thickness of the frame plates in such a way that you use a package of 1+2+2+1 sheet. In that case you can use a piercing saw for cutting out an entire 2mm sheet thickness to obtain a slot in the center.

centre slot

Producing the slot in the center for the gears.


Mounting everything together again for test fitting. Note the ends are profiled now and brought to length to fit the cab.

test fit with free running of gears

Test fit with free running of gears.


Profiling the top of the block for the motor and the gearbox. The motor sits in a length wise groove in the brass. Note without milling this is easier to produce with the 1+2+2+1 arrangement as with some advance thinking you can already file 0.5 mm off of the 2 mm sheets creating the slot in one go.
This photo also shows the gearbox coming into being. A 5 mm thick piece of brass with a slot for the wormwheel arrangement sitting on a 1.5mm axle. This block is insulated from the frame plates thus file a tiny bit from the top of the PB sides for electric clearance. Hardly visible but in the most left hand 1.5 mm hole you can just view the insulation layer of .1 mm white PS sheet.

undeep slot for motor

Slot for motor and gearbox with wormwheel.


Side view with the motor loosely mounted. This can be tested for free running with 2 wires. The gear box will be mounted with a M 1.4 screw tapped into the brass frame. The gearbox will get a 2mm fixing hole which gives us enough allowance for finding the optimal fit for wormwheel.

test for free running of gears with motor

Test for free running of gears with motor.


Here we test if the cab and footplate still fit over frame and motor. If that is OK we can mount the wheels.

checking clearance with the cab

Checking clearance with the cab.


Testing the running with the wheels, idler and coupling rod mounted and flywheel mounted. This one did pass the test and has the decoder mounted. The motor is simply glued to the frame with cyano glue and can be prised loose if necessary thanks to its polished stainless steel case. The close observer will note that this is the second machine and that is standing on 7mm tender wheels with overlays to avoid the oversized center of the normal loco driving wheels and the too large throw. These overlays are milled from a piece 5mm brass rod and predrilled. Slices of these are cut with a piercing saw and soldered on. This mounting requires a lathe to make a 0.5 mm center hole in the axle for a mounting pin. With the rods mounted you won't see that the second hole is out of center in the other end. As long as the throws are all identical this won't have any effect. The wheels also have their flanges reduced to .3mm and now have less acute angles for better running through point work. The idler is a job made from a blank made on the lathe and finished on the milling machine using a rotation table. The decoder is a DCX73 from CT-elektronik, Austria.

fitted for test run

Close to finish, front rods and brakes are still missing.


This is number one again with the brakes mounted using standard driving wheels. The rods are filed from steel as for steamers and are fitted in two parts. The long one also drives the idler gear. The paint was a quickie smear-over for a exhibition! Some cleaning and more careful finishing is on the to-do list.

in need a good paint job

Brakes mounted.


Work is started on the cab. For fitting awkward items, make a square plastic box, fit the cab and fill with shellac. This can be easily clamped and machined. However the second one was just treated by hand using a large file and sanding paper as zamac is pretty soft.

clamping difficult parts

A way of clamping irregular formed parts.


The new grill is produced from brass with parallel grooves cut on the milling machine. These need to be framed by 4 edge strips and that can be brought to rough dimension. The final finishing is done after gluing with 2 component epoxy. The non-millers just pull up their nose and produce this bit using a parallel sliding board and skrawker in a softer material such as polystyrene of course. Who needs a milling machine for building locos?

cutting a grill

Producing a new grill.


The new grill is fitted as well as a new chimney. On the left hand front we see a piece of louvre strip. This is made with a cutter at an offset angle of 20 degrees. This particular strip was made with the Unimat milling attachment that can rotate with respect to the normal on the cross slide. The strip needs cleaning up with glass fiber pencil. It can be made on the parallel sliding board as well.

fitting the grill

New grill, on the left is a piece of strip for producing new louvre doors.


See it coming together, the modified hood. Fitted grill, extra louvre door, first compartment door removed by scraping and sanding, removed silencer and the old chimney.

overview of new motor hood

Getting the details more correct.


A pair of modified r-t-r shunters. Some bits still need to be done but the major surgery was succesful. Note the now correct buffer beams complete with hoses and coupling hook for the MFK coupling.

A new coat and showing front and back

Put on a new coat and you have a pair of shunters.


Comparison of the two tone green NMBS livery with a still relative original black German DB version. If it is worth all this trouble? YES!

old and new

Compare results with original.

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permission granted for publication to
The 2mm Scale Association.
Author: Henk Oversloot © 2004
Revision dates: 19 december 2004, 18 february 2007,23 march 2008