Friday 8 January 2016

Steering wheel

The standard A7 steering wheel is 15" and does not give a good driving position (too close to chest and hands too far apart). I decided to search the inter-web and found a 13" wheel from a US hot-rod site, the only problem is there is no compatible boss. Nobody appears to make a boss for an Austin Seven (that I can find). The spline is 50 x 0.5mm deep grooves and 22mm in diameter.

I decided to make a boss and mount the steering wheel on the bottom of the boss to gain greater arms length distance from the driving seat. It turned out to be the most tricky engineering job so far in the build.

 Well I could bore you with the detail of how to go about this but it is difficult. You must have access to a shaper machine and either a CNC controlled rotary table or  a division plate (or be very good at setting 50 x 7.2 deg using a manual rotary table. Here is a picture of my CNC controlled setup.

The tooling manufacturing just to start making the part would put most people off:

* rt angle shaper tool + HSS steel cutting tip (foreground).
* shaper steady fabricated out of 5mm steel plate to support the job (the crap bit of welding surrounding the job).
* Shaper bed extension fabricated out of 10mm thick steel plate and a piece of substantial "I" beam (to support the rotary table etc).

That took me two days making things + a day to set it up and do a test piece and then manufacture the boss.

The result turned out better than my wildest dreams, it fits the A7 steering column like a glove.

Finished steering assembly

Complete with 750 club fixing nut motif
I have to thank Aliblast services (Ali McGill) for the use of his time and shaping machine.

Update 4th Aug 21

The steering wheel remains but has been made removable on a splined shaft as part of the Hilman Imp R&P steering upgrade. The shaft was made of round bright steel bar with McGill Motor Sport splined removable steering wheel kit, the other end was fitted with a knuckle joint. The hollow shaft was made out of a  scrap standard lamp tube and the ends were made out of machinable plastic. The alloy spacer was made recently to make the car more drivable.

Here is an Index page for the build

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