Tag Archives: BR 07

Converting a Bachmann BR 03 Shunter chassis to fit inside a Craftsman BR 07 Shunter (Pt3)

The bulk of the conversion is finished.

Chassis Modifications

As predicted (see Pt2), the rear of the chassis was the more difficult section to complete. I took to cutting down the back of the Bachmann chassis by grinding away the raised profile mouldings on the sides of the chassis (where the crank-shaft use to be). I lost a few cutting disks in this operation (goggles recommended). This aspect of the work was surprisingly easy.

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The next problem was that the Bachmann chassis’s bolt hole doesn’t line up with the existing body-hole at the rear of the chassis. Annoyingly, it is not quite distant enough to cut a new hole. So with a selection of drills and grinding tools in my mini-drill I widened the existing hole. You could likely get round this issue if you were still building the Craftsman 07 by moving the body hole, but this is not an option for me.

Next, I cut the remaining sections of the brass chassis to their new shapes. This was mostly trial and error; the main issues being avoidance of pick-ups and wheels. The rear sandboxes caused some issues yesterday which were resolved by sanding down the face of the rear brass section. Once this was complete I fitted the remaining details and all was looking good, and running well.

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Lubricator arm mechanism

My biggest achievement here was refitting the lubricator arm to the front axle. I lost the lubricator hand wheel in the cleaning phase (see Pt2). It flew out of some spring loaded tweezers. There was enough time for me to watch it flying across the front-room at great speed, never to be seen again. Queue lots of cursing. This was one of the smallest bits on the model. I cannot think of an easy way of fabricating a new one. So let’s hold our heads high and move on…

On ye olde chassis, the lubricator crank was fitted on top of the coupling rod washer. As the Bachmann chassis has bolts that screw the coupling rods in place, I decided it made more sense to fit it beneath the bolt (no soldering or gluing required). I widened the hole on the crank and fitted the lubricator arm, but the mechanism attempted to collide with both the coupling rods and the coupling bolt. A couple of washers later (one in front of the coupling rods and one thicker one within the lubricator arm mechanism) and the lubricator arm was up and running!

To be honest, this project is nothing to do with accuracy; small additions like the lubricator arm are more to do with the hours I spent building the darn thing first time round! So I am happy to see this work finally paying off, minus the hand wheel (sniff!).

Below is a video of the loco running:

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Converting a Bachmann BR 03 Shunter chassis to fit inside a Craftsman BR 07 Shunter (Pt2)

IMG_7184 (lowres)

Over the past week I have tried to answer three niggling questions regarding this conversion:

  1. How can I fix the Bachmann chassis into the brass kit body?
  2. How can I fill the open space from the cut-away chassis at the front of the loco (see the top image)?
  3. Can I refit any of the little details from the original brass chassis to the Bachmann one (sand boxes and the lubricator arm)?

As most of my time in this hobby is spent thinking about how to solve such problems (rather than actually doing anything) I decided, in the mean time, to see if I could deconstruct the old chassis.

The old brass chassis

I knew I wanted to retrieve the lubricator arm assembly and maybe the brake rigging from the old brass chassis, but I had foolishly soldered all the parts (including the axle bolts) into place. I also wanted to see if I could get the wheels off intact (for use in the future).

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After a bit of soldering-iron wrestling, I managed to get all the wheels, gears and motor away from the chassis. I could now strip the brass chassis back to bare metal.

Paint stripping

I have a range of chemicals (normally used for other household or DIY applications) that I use for paint stripping. For metals and brass, there is a chemical I use that can remove paint in a matter of minutes…Nitromors!

‘All Purpose Nitromors’ is a paint and varnish remover which I bought from Homebase or B&Q. This is one of those chemicals where you heed the warnings on the tin! This is vicious stuff! On my first trial with Nitromors (stripping white metal figures) the chemical ate through my rubber gloves and burnt my hands!

It will eat plastic, so if you have any plastic detail on a model, it is very important to remove it. It will also eat any glue joints, so unless you have soldered your model together, expect it to fall apart too (such qualities can also be quite useful).

I have a small metal pie-tin than I fill with Nitromors and then drop my models in (I think plastic containers are too risky).

As expected, after a few scrubs with a toothbrush, the brass chassis was back to bare metal. After a good rinse and scrub with soda crystals I dropped the chassis into my sonic cleaner, which removed any remaining residue.

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I noticed after this step that the solder joints had become quite brittle, which makes me wonder whether the sonic cleaner was the cause (I hope not).

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Bachmann Chassis

As the chassis appeared a bit more fragile after the ‘purge’, I decided to cut off the brake rigging (deciding that I wasn’t that precious about including it on the new chassis).

I then noticed that the Bachmann chassis was actually thin enough to sit inside part of the old brass chassis frame. I decided to cut the front end of the brass chassis off and change the position of the spacers, which miraculously allowed me to refit the front end of the brass chassis around the Bachmann one, thus:

  1. filling the annoying gap at the front of the engine;
  2. creating a front mounting for the chassis; and
  3. retaining the front-end chassis detail

Result! Granted, the rear section will not be quite as simple, but I will tackle this next.

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Converting a Bachmann BR 03 Shunter chassis to fit inside a Craftsman BR 07 shunter

The running quality of my locos is important to me. Irrelevant of how well made they are or how detailed, if they cannot run along a piece of track smoothly or cross a point without stalling, then the loco is of little use to me.

The long suffering Craftsman BR 07

My BR Class 07 Shunter is one such loco that looks much better than it runs. This Craftsman kit was purchased partly completed in 2003. One of the areas completed was the chassis, which was quite jerky and the rods appeared to be binding. I decided to deconstruct the chassis and start again.

I rebuilt the chassis with a new set of wheels and a new Mashima can-motor. I spent a very long time making sure that the chassis was set up properly so it would run smoothly. This was all done on a straight test track. I didn’t realise that the engine would not enjoy going round curves or crossing points.

I persevered, redesigning the pick-up arrangement on the wheels. I was also trying desperately to find a method of keeping the motor from rocking backwards and forwards, which made the fly-wheel skim the inside of the bonnet. My attempts at stabilising the motor eventually led to the DCC decoder blowing up, and the 07 quickly went back into storage (it was that or out the window).

Craftsman chassis (left) and Bachmann 03 chassis (right)

After purchasing a couple of the new Bachmann Class 03 Shunters, I started to wonder whether one could be adapted to replace the Craftsman chassis. I did some quick measurements and decided it was worth a go.

Body modifications

The first thing I did was widen the opening for the chassis and cut away some areas inside the 07’s body cavity. This modification also required removing the floor of the cab and cutting away the control panel (no doubt much easier if the body has not been constructed). The opening into the rear bonnet also required opening up slightly for the DCC decoder harness.

It looked as if the 03’s chassis may actually fit inside the frames, but the chassis itself would require some modifications.

Chassis modifications

The main modification required was to remove the front end of the 03’s die-cast chassis. The length of this section of metal restricts the chassis from sitting where the 07’s wheel sets are prototypically positioned. My new hacksaw was used to cut away the front of the chassis, with some masking tape around the motor core; stopping any metal shavings getting inside.

Once this was finished I unscrewed the axle nearest the crank shaft from the coupled wheels and used a mini-saw to grind away the coupling rods so the cranks could be removed. At this stage I was a bit nervous whether the new chassis would still operate properly.

Reinvigorated

The new chassis runs very well and sits as low as I hoped it would. The 07 will now happily cross the point work of Brewery Pit. I next need to reattach some bits to the 07 that unfortunately fell off while I was accosting it with a mini-saw. I also want to see if I can fit some of the former chassis’s little details to the new one.

I am fully aware of the inaccuracies in the chassis including: the wheel sets not being entirely accurate, with a slightly different spoke arrangement; and the brakes being fitted the opposite way around, but (as I said at the start), if I have to compromise the accuracy of the loco to ensure I can actually run the darn thing, then so be it.