I want to lengthening the sierra steering shaft as per the Avon book. I don't fancy paying for one from tiger. Is there anything I need to know before doing this. Obviously, I'll adopt a "belt and braces" approach, but what have others done.

I found a piece of close fitting steel tube of sufficient length - I think it was electrical conduit tubing.

I cut the ends at an angle - to give some mechanical grip if the welds failed. Then welded that to both sections. High heat, low wire feed to ensure plenty of penetration

Then I drilled through the tube were it overlapped the original shaft in two places (at both ends). Then I 'puddle' welded the two again.

Finally I drilled all the way through the tube and the original shaft (in the overlap area but at 90 degrees to the 'puddle' welds) and put an M4 bolt through with a nyloc nut on the end.

The nuts are not tight - the idea is to use the bolt to check the weld integrity. If the bolt/nut rotates in the hole (through the shaft/tube) the weld is still holding.

It's a belt & braces method but I don't fancy the consequences if it fails at speed

Make sure the tube has good wall thickness. Be careful when drilling holes and puddle welding. My uncle is coded welder and does not recommend this. It is easy for the tip to arc out on the outer surface first leaving a void in the middle = weak spot.
The jury is out on drilling after welding to fit the M4 bolt - doesnt this weaken the assembly??

seeing as none of the DIY shafts are subjectied to torque durability testing (std test in steering column production) you must satisfy yourself that you are happy with the end result.

You cant have enough penetration

Agree with everything you say Darren.

My tube had a wall thickness around 3-4mm.

For puddle welding I drilled the holes to 13mm diameter through the tube, letting the tip of the drill penetrate the solid shaft.

Proceeded to weld from the centre of the depression outwards in a spiral form - deliberately to reduce the chance of voids as per your Uncles recommendations.

Max power, low wire speed - glowed for 1-3 minutes afterwards.

HTH

quote:

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glowed for 1-3 minutes afterwards.

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I used a Steering Drag Link off a Land Rover (90 or 110 - Coil sprung model, the one from the steering box arm to the Wheel)

The Sierra shaft when cut in half fits almost perfectly in the LR shaft hole. I just opened up the two existing slots in the end (where the track rod end goes) and welded along there. Also drilled a hole before I put the sierra bits in, and then puddle welded that.
This is a tube with about a 4mm Wall thickness. If its good enough for steering 2 tons of Land Rover, it will be OK on 600Kgs of Viento.

If you cut the sierra downshaft in the middle you are 5" away from the u.j. I don't think it's going to get warm enough to do it any harm. I noticed in the spares shop near us they do the rubber donut bit separate, you grind the rivets off the old ones and replace them with M8 bolts. When I did my first one I just cut the shaft pushed the ends in a tube and welded round it and it's still alright so I think the next one will get the same.

You dont have a piccy of the donut, or a shop name / phone number.

Mines fine but it is a bit old.

I was a fair way away from the joints wth the welding..

Im also looking at my steering colum and finding that it needs extending due to it fowling the dash board and also for a better driving position due to a bit of a lancky situation going on.

I have enclosed a picture of the sierra column which is sitting in my luego locost chassis and wanted to know where people recommend cutting and welding ...

position 1 or 2 or none ?


steering column circles