A Special Builder's Notes


The Special Builder's Breakfast Club

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02 November 2012

A Good Day's Work.

Though there's not a great deal to show for it, I have at least cracked the new linkage for the gearbox. As usual, one or two bits had to be done twice as my guesstimates were a bit short one end and the shifter lever hook-up is not yet complete. I started by making an aluminium saddle - this is all a mock-up of course, the real thing will be 4mm steel and a bit more elegant - and cutting a hole in the side so the selector arm could get through to the base of the gear lever.

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At this point, the selector arm had a 90 degree bend in it which is why the gear lever hole on top of the saddle is offset forwards. The small cross on the side marks where the hole for the main shaft goes. I later discovered the error of my ways. The main shaft must be in line with the selector arm otherwise it all gets in a muddle and before you know it you've got a geometric lock. So the gear lever hole was wrong as well.

A new selector arm was made up and the mainshaft re-positioned further back. The selector arm had also to be dropped by 1/2" as everything was too high to accommodate the swivelling block (milled the night before) which connects all the gubbins to the gear lever.

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Then I found that the new selector arm was 1/2" too short and so another one had to be made up. (I'm really pleased with the Myford; it's almost a pleasure to have to do everything twice!) Finally, a new gear lever hole was cut in the top of the saddle and the other hole for the mainshaft was made.

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Then came the test and I'm delighted to say it works. I've just got to firm it all up with some collars on the mainshaft and I also need to shorten the vertical shaft which operates the selector lever and I should be home and dry. I'm almost not going to bother with the shifter lever mechanism at this stage at it's so simple - it doesn't have to go around any corners, just straight from the shifter lever to the end of the mainshaft. The other thing that I'll have to do is weld a block to the gearbox casing so that the nearside of the saddle can be secured - there's no handy studs or bolts on the nearside. I think I'll take advice from Learned Counsel on that front; there may be some special technique for welding steel castings. I also have to make sure that I don't restrict access to the  gearbox  dipstick.

Which reminds me. I notice that Learned Counsel has got the Jowett Joystick chassis back from the powder-coating people. They've done a lovely job although I understand that the Waxoil the previous owner had put in the chassis tubes got a bit smelly in the oven. I've had a few more bits powder-coated as well - the rear brake back plates and the spring hangers which means I can assemble the springs on the chassis permanently - that'll be another good day's work.

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