G3 Made Simple

It ran very smoothly on the rolling road and will run through my 8ft radius turnouts.

If I build a J15 in the future, I will have to replace my 8ft turnouts with 3 metre radius turnouts.

I'm very pleased with it and can't wait to take it to a Society Get- Together, to give it a good "running in" around a garden circuit.

I've now started work on the artwork for the brass etchings for the body.

Costings

6 'bespoke' wheels from Mark Wood £175

Motor /gearbox (GRS) £100

Laser cut frames £25

Hornblocks (Williams Models) £36

Battery pack (Strikalite) £35

RC receiver (Peter Spoerer) £85

£456 in all : Slaters wheels would have been marginally cheaper but are not available in the correct pattern/size for the J65 and I prefer Mark Wood's wheels in any event.

SUMMARY OF MAIN POINTS

*****************************

Tools used (in addition to usual screwdrivers, nut spinners/spanners, etc.).

80w Weller soldering iron

small hobby drill

hand reamer

Turbocad deluxe for the drawing (cost probably around £50 now)

*****************************

Contacts

Williams Models www.williamsmodels.co.uk

Mark Wood Wheels www.markwoodwheels.co.uk

Garden Railway Specialists www.grsuk.com

Peter Spoerer www.peterspoerermodelengineers.com

Strikalite (batteries/chargers) www.strikalite.co.uk

Geoffrey Nicholls

May 2014

Geoff is a recent convert to G3 and this is his first attempt at scratchbuilding a loco "on the kitchen table".

Anyone planning their first scratchbuild will find his "learning curve" notes helpful and, hopefully, inspiring.

**************************************************************************************************************************************************

This is my first scratch built loco in any scale and is battery/electric with radio control.

Being a member of the Great Eastern Railway Society and living in the area formerly served by the GER, the LNER J65 (GER E22) 0- 6- 0T (commonly referred to as a "Blackwall Tank") was a natural choice.

My first G3 kit- built loco was a LSWR Class O2 0- 4- 4T from a Garden Railway Specialists (GRS) kit.

I originally thought I'd emulate the GRS method, using laser cut frames with GRS frame spacers, hornblocks and a compensation beam, thus keeping the soldering of steel to a minimum.

The J65 was to be the trial run for a more ambitious project, an Eastern Counties Railway Gooch class A 2- 2- 2WT, so I decided the J65 had to be built to the same standards, to prove the method, and that meant a more prototypical frame spacing than the standard GRS kit (with its 49mm spacers). I discussed my proposals with several G3 Society members and was guided by their experience.

I do know my limitations; I can't cut a straight line in metal to save my life. Fortunately, I'm reasonably good at CAD, so drawing frames for laser cutting was easy to do. The frames are 1.5mm steel, because that's what everyone else does. The design was based on the way the Manning Wardle tank loco frames in the Williams Models kit are constructed. A combination of horizontal and vertical spacers, with tabs fitting into slots in the frames, creates a stable structure which is easy to hold together while you solder it. Holes were included for rivets, to locate the hornblock guides in position while soldering.

As I mentioned earlier, I had originally intended to use GRS brass frame spacers, but they are only 49mm long and I wanted the frames to be as near prototypical as possible, as that was what I would have to do with the ECR 2- 2- 2WT.

The G3 Society standard for wheels is 58mm back to back. I then added 2mm for the two axle bushes and found that, even with 8' 0" radius curves, I would need very little lateral axle play, so I settled on 52mm spacers between the frames.

I elected to use hornblocks supplied by Williams Models. They are designed to be sprung beneath the block but the J65 had it's real springs underneath, so I turned the hornblocks upside down. At rest the loco frames will sit on the tops of the screws on the hornblocks of the outer axles (springs fully compressed) but there will be 1mm play above the centre axle. The hornblock springs will then push the axles down when uneven track is encountered.

The cast iron wheels were obtained (ready finished and quartered on their axles) from Mark Wood and the motor/gearbox is a standard unit as supplied by GRS with their kits.

The coupling rods are laminations of steel : Originally I intended having the coupling rod fluting ground out but have now added etched nickel silver overlays.

Adding the overlays means the rods are thicker than originally planned and the brass coupling rod bushes supplied with the wheelsets are not now long enough. The original bushes provided by Mark Wood are threaded inside to match the M2 screws. I thought I could just replace these by longer sections of 3mm brass tube but the tube was too loose on the screw ; it was impossible to tighten the nuts without causing sufficient eccentricity to cause the coupling rods to bind.

I ordered a new set of threaded bushes and, having fitted these, II bought a rolling road and tested the chassis under power. Holding the motor up in my fingers, I could still feel a 'pull' with each rotation. I found one of the rods had slightly distorted during soldering the layers of the steel together, leaving a hole out of alignment.

Some fettling in the the vice with a file has fixed this.

Next, I cut some lengths of coil spring and fitted them loosely on the hornblocks. The frames just about float on the blocks but will sit firmly when the batteries and body are added. It will be necessary to fix the springs to the hornblocks (I used Araldite) to stop them twisting under compression.

I tried pushing it along on my track; an 0- 6- 0 with 13' 6" wheelbase (a scale 182.25mm) and, with 55mm width over the frames, will happily negotiate 8' 0" radius turnouts, although that leaves no further lateral play in the axles.

A "Strikalite" battery pack of 12 AA 2100mAh batteries, the Revolution RC receiver and a DPDT switch (for switching the batteries between powering and charging), were mounted onto a temporary "footplate" of plywood.

Gauge 3 Society member Geoff Nicholls explains how to scratch- build a Gauge 3 loco chassis with the minimum of tools and skill.