Unfortunatly the manufacturer of my chassis omitted to weld the gearbox(type9) mounting plates to the chassis box section.
Can anyone recommend a substantial way of fixing plate to the box section without welding, as I don't want to remove the powder coating. Someone said rivit nuts but I was concerned if they could fail under the torsion force? Could putting bolts through deform the box section?

Cheers for any advice,

John.

bolts could be overtightened, crushing the tube. This could be avoided with some washers, maybe a drilled bar of 25x3mm flat.

Use a crush tube if you want to get technical.

Drill a hole bigger than the bolt you are going to use, big enough for a bit of pipe to fit in that the bolt will fit though. Cut the pipe off a little shorter than the thickness of the tube (but not much shorter only 0.5mm say). Slide the tube through, bolt through it with a washer each side. Shoudl grip well enough, and you wont crush the chassis tube.

Hope that makes sense...

David

makes sense too me, short of welding thats goto be a close second best n what i was about too suggest.

although its the best option,surely that would seriously weaken a major chassis tube...for a gearbox mount your going to want a 10 or 12mm bolt, then the tube around it, so that (for a 12mm)would mean drilling maybe a 15mm hole in the tube..there wont be much metal left in the sidewall.......or does the bolt with tube replace the lost strength??

I would say weld it and repaint your powdercoat...It won't be seen..even though you know it's there.

The bolt that holds the box to the plate is a big one ie 10mm but doesnt the plate hold to the chassis with 4 x8mm bolts??

using a 10mm tube would take no more metal away from the tube than a rivnut??

Defo would not use rivnuts for the job as I doubt they are upto it?????????????

I have seen the front tubes bend at the point of the rivnut when spanked(head light brackets held on with said nuts )

just my 2p worth

It would've been better if they'd 'remembered' to weld them on in the first place....eh?

Anyway thanks for the advice all, much appreciated. Because of my lack of welding gear/skill I think the 'crush tube' is the best option.

Cheers, John.

To make the crush tube more effective only drill one side big enough to allow the tube through and leave the other side the size for the bolt. This way the box section is clamped and crushed, not just crushed. If it is just crushed it could eventually deform and the gearbox would then become loose.

An accurately fitted crush tube is the only way to do it, in any case this isn't a major part of the structure.

I wouldn't get too paranoid about damaging powder coating.


I thought that with mine to start with but have now done loads of welding and touching up (use plasti-kote super enamel)