I'm looking to fit a rear seat to my van, the existing bolt holes are slap bang on top of a chassis rail so I will need to fabricate something.
Unfortunately there's a lot of obstructions underneath so I'm limited as to where I can drill through and get a decent sized spreader plate in (ideally I'd have liked to bolt right across the width of the van). I've marked on an image roughly where I can get through, a concern I've got is that it is mainly only possible to drill in the space between the seat mounts - will this be strong enough?
Obviously safety is critical here, so I'd rather over engineer this.
A few ideas I've had:
1. Weld a wide piece of flat bar (possibly 200mm - 300mm wide, unsure on thickness was thinking 6mm?) width ways across the van to each of the front/rear existing seat mounts. This should mean I have a good amount of flexibility where I can drill holes. Downside would be removal of the seat would be really difficult, but perhaps not a deal breaker.
2. Bolt box section vertically in as many places as I can (was thinking 50mm x 50mm x 5mm?), I'd probably manage to get 4 of these fitted. Then bolt flat bar/steel plate to the top and bolt the seat to the flat bar. The seat would hopefully be removable, but not as secure as parts of the flat bar would be floating?
3. Box section widthways (probably 100mm x 50mm x 5mm?) and bolt the seat to the box section. This wouldn't leave me a lot of flexibility vertically (which would be helpful), also I'd have to drill access holes to get a socket on the bolts through the van floor which would weaken the box section.
Be interested to hear peoples thoughts on how they would tackle this as well what thickness of steel you'd use etc.
Thanks in advance for any help!
Unfortunately there's a lot of obstructions underneath so I'm limited as to where I can drill through and get a decent sized spreader plate in (ideally I'd have liked to bolt right across the width of the van). I've marked on an image roughly where I can get through, a concern I've got is that it is mainly only possible to drill in the space between the seat mounts - will this be strong enough?
Obviously safety is critical here, so I'd rather over engineer this.
A few ideas I've had:
1. Weld a wide piece of flat bar (possibly 200mm - 300mm wide, unsure on thickness was thinking 6mm?) width ways across the van to each of the front/rear existing seat mounts. This should mean I have a good amount of flexibility where I can drill holes. Downside would be removal of the seat would be really difficult, but perhaps not a deal breaker.
2. Bolt box section vertically in as many places as I can (was thinking 50mm x 50mm x 5mm?), I'd probably manage to get 4 of these fitted. Then bolt flat bar/steel plate to the top and bolt the seat to the flat bar. The seat would hopefully be removable, but not as secure as parts of the flat bar would be floating?
3. Box section widthways (probably 100mm x 50mm x 5mm?) and bolt the seat to the box section. This wouldn't leave me a lot of flexibility vertically (which would be helpful), also I'd have to drill access holes to get a socket on the bolts through the van floor which would weaken the box section.
Be interested to hear peoples thoughts on how they would tackle this as well what thickness of steel you'd use etc.
Thanks in advance for any help!