An Excursion in Chassis Building

I have been tinkering with a project that is outside my usual comfort zone and quite honestly, for a time it threatened to remain so... I've been following the progress of Mark Clark's "Locos'n'stuff" range for some time and keeping an eye out for anything that may be suitable for use in O9. The new 'Larger diesel bogie' offered some hope as 9mm gauge was included in the specification. So I ordered one, with the possibility in mind of making a less chunky chassis for the A1 Models Keef than he Bachmann 'brick'.

First impressions were good, the etch neat and the parts well packaged, but my first read of the instructions was not too hopeful, as there was no explanation of how to fit the layshaft, gears and wheels etc. Thinking I had a missing page I contacted Mark, who gave me the missing details but admitted he often missed areas familiar to him out...  

The build of the etched parts went OK, the frames were shortened to be the same length as the Bachmann chassis and the wheelbase set at 22mm. It has to be said that building to 9mm gauge gives very little clearance to get the soldering iron in! I then moved on to getting the layshaft in place, tricky but achievable with perseverance. Then came the bit I was dreading, the wheels... I had purchased a new desktop vice to assist (well, I say purchased, persuaded a relative to buy it for my birthday!) and having got the gear fixed in centrally I pressed the first set of wheels into place, and it is important to say I was looking from above the frame... To my horror disaster awaited underneath...

With the wheels pressed fully on the axles (as recommended), the frames were bent inwards. I contacted Mark and he advised to remove them, straighten the frames and then file the bearing faces flat to the chassis side. This time the wheels went on OK and after some adjustments I was able to give it a test run, having fitted the motor and drive belt into place. With pickups fitted I was able to run it properly.

Test running started to show up a downside of the wheel profile which is aimed at wider gauges, with a thick, rounded flange. There was a very narrow sweet spot between getting the flanges between the rails and the back-to-back through Peco 009 pointwork. This was further exasperated when trying the chassis on the 6 and 5 inch curves of the 'Getting Something Moving' project, where the flanges were bumping up over the rail head in places. There was not enough flexibility in the setup for curves this sharp.

On a whim I removed the wheelsets again and replaced them with a set of the much finer Greenwich 8mm wheels as the central axle size is the same. With a few tweaks to the pickups these have bedded in well and on test on the sharp curves rides much better.

Whether I'll repeat this excursion into chassis building I'm not sure, I haven't yet decided if the Keef will actually receive this chassis or if it will be put aside for my Narrow Planet/James Hilton Perrygrove 'Jubilee' kit, as I don't really want to put that on a Kato chassis with overlength wheelbase.

The thought did occur to me that in 14mm or 16.5mm gauge form this chassis could be used under the A1 Models Keef to give an O14 or O-16.5 loco... Hmm...

Colin