I had originally planned to go to Kettering show this weekend with a stop over on Friday night. Taking the decision not to go has given me an extra couple of days of thinking/modelling time in which to really get my head into the inside motion.
Fellow modeller Paul Penn-Sayers had offered to cut out a motion plate for the J6 for me. Paul has also supplied lots of information and patiently answered my ‘newby’ questions regarding inside motion for which I am eternally grateful. While I fully intended to take up the offer events somewhat overtook me.
While studying the GA drawing to work out which bit was which on Wednesday evening I had the thought of importing it into Inkscape (the drawing package that I use to draw for the silhouette), rescaling it to 7mm scale and then highlighting the components that make up the motion so that I could see what they are.
You can see the difference in the layout of the motion compared with the Midland variation in which the motion set from Laurie Griffin is based – below is a snip from the LG instructions.
While I was doing my stuff in Inkscape, Chris suggested using my silhouette to create a template for the motion plate to test whether it would fit between the frames etc. I thought that a great idea and within a very short space of time I had drawn up and cut this
I used that to transfer the measurements onto a spare frame spacer and drilled/cut filed it out. Due to using it as a template to scribe around, some of the measurements were fractionally over size, while the internal ones were slightly undersized. I kept filing until the slide bars fit and I got this. – I added the framing top and bottom afterwards.
Looking at Paul’s and Nick Dunhill’s superb motion plate examples, I realise that I will have to file some relief in the tops and bottom of the slide bar seats/openings in a similar manner to the centre opening where the eccentric rods will pass through, in order to allow for the up/down movement of the piston rods.
This is it in the frames – held by a blob of Blue tack
Although as I say I am very grateful to Paul for his offer to cut one out for me and looking at the example posted by Heather Kay on Western Thunder, it would have been of a much higher fidelity than my first effort has achieved but it’s a skill learned and Paul’s help has helped me to make sense of GA’s which has previously eluded me – all the lines blurring into a shapeless mass. Another skill which will only improve with practice and should translate into better quality models at the end of it.