4 replies to this topic

[hoggy]

Hi, is 6mm steel too thick to use as internal spreader plates for a bolt in roll cage?

Also I was going to use plates on the underside of the sills and wheel arch, are these necessary or will the washers suffice?

 

Thanks.

[fwdracer]

3mm is more than adequate material thickness. A spreader plate on the outside is belt and braces - good thick washer will suffice.

[MRA]

RAC blue book used to specify the size of the plates as 6"x6" and on both sides,

 

3mm is more than adequate material thickness. A spreader plate on the outside is belt and braces - good thick washer will suffice.

The plate thickness is almost irrelevant once it gets to the same as the shell thickness, what you need is for the plate to flex in a roll and not be so rigid as to punch through the shell, as it flexes it will become in tension which can carry 3 times that of the same area in shear.  this should apply to both sides, a washer need to be quite large so it doesn't tear out.

[hoggy]

Thanks guys, I guess going by what Mra is saying then 6mm may be too thick.

[MRA]

I also round off the corners as any sudden change in direction will become a stress raiser, belt and braces are sometimes the only thing that keeps us safe.