Wednesday 9 December 2015

Custom tie bars

The front suspension has tie bars from the chassis (centre point ) to the stub axel mountings. These tie bars prevent the geometry changing under load. The suspension was manufactured by Bowden in the 50-60's as such the track width is greater than standard A7. I could not find any such wider tie bars on the usual s/h sources so I had to fabricate some. The suspension end had to be heated to yellow and bent. The tie bar tubing was cut out of  25mm x 3mm thick CDS. The cup ends were turned out of 38mm bright bar and the axel ends out 25mm bar as pre attached diagram. After turning the 43mm long section it was grooved and bent to the correct angle. The groove is necessary to keep the bend angle tight, I welded it up afterwards.

Chassis end
Upright end

The finished tie bar vs original
To secure the tie bar end I used a full nut and  one half nut made out of an old castle nut but with the same thread and a larger spanner size cut down on the lathe. The half nut is on the inside. There are two thrust washers cut out of 30mm bar 3mm thick. The thread by the way is a 5/16 x 16tpi UNC thread form available from Tracy Tools.

Update 4th Aug 21

The tie bars were subsequently modified to have jack screws to adjust their length as part of a Rack and pinion upgrade.

Here is an Index page for the build

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