The off set mushroom in the sierra up right is only held in place by pinch force, and to pass SVA/IVA many centres have required a second method of fixing. Many builders have simply drilled a hole in the casting into the mushroom and tapped for either M6 or M8 screw.

Now for some reason, I really did not wish to do this, feeling that drilling into a highly stress cast steel part, could cause possible stress fractures in the future! I may be wrong but still did not wish to do this, so I worked on another method of second fastening.

In the front hub there is a squarish void, as seen in this picture.


This gave me an idea of making a hook style clamp arrangement, that would lock into here and bolt into the mushroom, the next picture gives a better explanation of what I mean.

The small hole will let any water drip out (was really there from the lathe work), the larger hole is clearance for an M8 bolt.
This view shows the bottom clamp, turned to fit inside the mushroom!

These are handed so two made up and more welding to beef-up the clamp. The top of the mushroom has two holes, both off centre. One is tapered to match the Transit drop link, the other threaded m8.




The m8 bolt pulls the mushroom and clamp together against the upright collar and stops the mushroom from coming out of the upright should the pinch bolt come loose.

Of course, the idea is it never comes loose, so use of split washers and thread lock on the m8 and m12 bolts certainly helps.


This is my way of 2nd fixing, may not be ideal for many, as you do have to have things like milling machine and lathe to accomplish it.

I would welcome, you views.

Adrian.

Clever idea...

Although I didnt have any issue at SVA with no second means of attaching the items together.... the tester was far more interested in sharp edges and menial thnings.... silly twunt!

I needed the additional fastening and simply tapped an m6 thread through the front of the upright and used an allen head as a second pinch bolt, hich he was happy with.