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12 June 2011 Going up – spanners and fishplates...

In between working on the models we have shown recently I have been experimenting with spiral ball lifters. I started with the standard fishplate lifter, which once you get going on doesn’t take too long - honest! With that built I was interested in having a go at a spanner lifter. Inspired by Max Morris and Graham Jost’s efforts on this subject, I thought I would have a go at coming up with a simpler means of fixing the spanners using a threaded rod. Max had fitted bosses to the centre hole of the spanners and fixes them to a Meccano rod, Graham had made an elaborate arrangement of rods in bush wheels to keep his spanners in the correct orientation.

My first attempts involved attaching the spanners to a threaded rod using a nut positioned in the centre hole with a washer either side secured with nuts either side of the washers. Good plan but the nuts are thicker than the spanners preventing the washers clamping the spanner tight. I then realised that the small rubber pulleys, supplied with most of the modern sets, will fit inside the centre hole quiet firmly. After some experimentation this proved unsatisfactory as it did not hold the spanner firm enough on their own and were too big to be squashed into the centre hole of the spanner. Then I realised what would do the job, those small white rubbery washers that are used to hold wheels and gears on to normal and tri-axels. Again a modern part that we seem to collect by the bucket load (well small bucket!) and hardly ever use.

The technique I used was to start by locking a threaded coupling to the end of a treaded rod using a nut. Then drop on a washer and force a rubberised plastic washer down the rod. This is best done using a short strip or fishplate to force it down over the treads. Next the spanner is dropped over the rubbery washer and a standard washer is applied over that. Tightening a nut down onto this assembly will lock the spanner in place as the small rubbery washer is forced into the space around the rod centring the spanner the washers then clamp the spanner in place as the nut is tightened. All that is needed is to repeat the process all the way to the top of the rod.

Rubber washers push fit into the open ended spanners

When using stamped washers you will see there is a smooth side and a sharp side. Take care to position the sharp side to face the spanner on each side. Oriented this way, when the nuts are tightened the washers will grip the spanner more securely.

Next job is to design something to use them in. I have an idea for building a marble bouncer/ping pong ball lifter/ball bearing roller all in one model where the separate balls interact with each other but that is a way off yet.

Ralph.

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