Making seat mounts from aluminium

[Noj_1991]

Hi all,

I'm hoping one of you clever people can help me with whether my seat mounts will be suitable or not.

I've done loads of googling and forum searches, but I just can't get my head around it.

I have a 630mm gap that I need to bridge and mount a seat too, so the seat will be directly above the gap.

If I got 2 x 670mm lengths of 5mm thick, 60mm wide 6060 grade aluminium flat bar, and bolted them across the gap (with a 20mm overlap on either side) and then subsequently bolted the seat to these bars, would it take my weight (80kg)

What about if I jumped on it?

 

[berkeman]

Hi all,

I'm hoping one of you clever people can help me with whether my seat mounts will be suitable or not.

I've done loads of googling and forum searches, but I just can't get my head around it.

I have a 630mm gap that I need to bridge and mount a seat too, so the seat will be directly above the gap.

If I got 2 x 670mm lengths of 5mm thick, 60mm wide 6060 grade aluminium flat bar, and bolted them across the gap (with a 20mm overlap on either side) and then subsequently bolted the seat to these bars, would it take my weight (80kg)

What about if I jumped on it?

Welcome to the PF.

Can you post a picture or sketch of the situation? What is the seat mounted to?

 

[Noj_1991]

Welcome to the PF.

Can you post a picture or sketch of the situation? What is the seat mounted to?

Cheers for the welcome.

After getting my hands on some aluminium, I can see it's not going to work, it flexes too easily.

I appreciate box section would be better- but would it be enough?

 

[ChemAir]

Typically, in a car, you will support off of tubing. There are a few that make formed aluminum as a base, and it uses the seat for additional rigidity. Kirkey has a variety of brackets that you may get ideas from. There will typically be one of these on each side of the seat, but I don't know that it will span the distance you have in the OP. Flat aluminum will not do a good job making this span. For aluminum, you will need a bend to give you a vertical structural element for strength. 6063/6061 are not considered formable without annealing. 3003/5052 are better aluminum selections for formability, if you make them yourself.

Typical Kirkey bracket

Other seat mounts that may give you ideas:
https://www.swracecars.com/store/Seats--Seat-Mounts-OSCAR_248.aspx
https://www.cachassisworks.com/p-358-tube-style-seat-frame-for-full-chassis.aspx
https://www.cachassisworks.com/p-357-stock-floor-seat-mount.aspx
https://www.appliedracing.com/search?query=seat+mount&submit=Go

If this post is not for a race car or the like, I apologize for sending it down a rabbit hole.

 

[Nik_2213]

Slightly off-topic but, if I did such to a car I owned, I'd have to declare it to the insurance who may require a formal inspection. Similarly, formal and semi-formal competitions have rigorous safety inspections. May I suggest you ask those authorities sooner rather than later ? BEFORE you 'cut metal' ?
Based on their findings, you may be able to eg nest box-sections, add spreaders, double brackets etc etc to satisfy safety concerns.

Be aware that you, at rest, may be 80 kg. Your butt arriving rapidly will provide a bigger shock-load. Washboard surface will double it etc etc...