Outer Limits 4x4 Board

is it legal to weld to your chassis? all i want to do is weld some 10/12mm pads for slider/sidestep mounts 3 per side. have been told you cant, have been told you can only weld the side of chassis and vertical only? anyone know what is legal in qld?

Pretty sure this has been gone over a few times, so a little searching and reading first may help then consult your engineer.

BTW, vertical welding only is NOT good

In NSW it's illegal to weld on the flange of the chassis but the sides of the rails are fine. I'd say that rule is probably Australia wide.

Cheers Mick.

by welding you heat affect the chassis. makes a weak point.

do you really want to do that to the main part that holds your car together ??

talk to an engineer. that way when your sliders brake off and rip the chassis rails apart you can blame him for the cost of a new car.

i would never sell anything that welds onto a chassis. my public liability insurance would never cover it !!!

ditto above

I had to get a crack welded, easy just took to an engineering firm on Sunny Coast who were happy it was non-structural location and repaired

fumduk3 wrote:is it legal to weld to your chassis? all i want to do is weld some 10/12mm pads for slider/sidestep mounts 3 per side. have been told you cant, have been told you can only weld the side of chassis and vertical only? anyone know what is legal in qld?

This might be a stupid question but why weld to the chassis ? Why not bolts and a sandwich style set-up ?

fumduk3 wrote:is it legal to weld to your chassis ?

Yes ....... BUT .....




you'll need 2 things or it WILL end in fuglyness

1/
location, material size, & welding size MUST be ENGINEERED and paperwork supplied to support this

2/
A certified chassis welder's ticket holder is the ONLY person authourised to weld a chassis





Degree of dificulty to get both of those ..... 9.9


Which is why eveyone BOLTS additions to the chassis'





ofcourse you can always grab ya welder and just do it
But dont EVER have an motorvehicle accident or you'll need both of these 2 things....

1/ really numb ass ( cause your gunna get screwed in a big way )

2/ lots of money


Kingy

I've seen a few sliders with brackets welded to the chassis rails done by 4WD mobs and was looking at doing the same style because it looked a better design than the sandwhich plate. Then again i might look at reinforcing the factory mounts for the side step so not to worry about welding to the chassis. But i have had to cut n shut a few of those nuts the factory weld to the inside of the chassis after breaking bolts and the nuts breaking off when removing tow and bull bar because previous owner hasn't used grease etc. So going off what some have said that even this is illegal to do? Isn't it worse towing with a tow bar that has only 3 bolts holding it instead of the 6 its supposed to have?

Spoke to an engineer a while back about fish plates welded to the chassis for extra bracing, he reckond he could sign it off. Would be nice if thoughs fish plates had captive nuts on the back, would make bolting slidders on easy

from what i have been told as long as you dont weld on the corners of the chassi or vertically you can pretty much do whatever but your not allowed to weld anything to the chasi that is thicker then the chasi but it still all has to be enginered so best talking to the engineer that is going to engineer it because they all have there own ways they like thing done

This is for Nsw.

http://www.rta.nsw.gov.au/registration/ ... v_2007.pdf" onclick="window.open(this.href);return false;

i have had 2 roadworthy certs done and 3 dept transport inspections. neither of them have said anything about the sliders i welded to the chassis.

whats the difference between small plates for sliders to bolt to and welding engine mounts on?

deano86 wrote:whats the difference between small plates for sliders to bolt to and welding engine mounts on?

Most cars have a secondary frame for the engine, a K frame as such, this frame is bolted to the cars sub chassis

Its considered 'ok' to weld to the K frame because the risk of injury is very low from an engine breaking free & tumbling down the road whereas the risk from a slider skittling someone due to a weld failure is considered far higher.

With 4x4's the cross member that carries the engine isnt generaly considered as part of the chassis so welding to it is generally accepted as a borderline "ok"
In reality it should also be engineered and I have in the past been asked to certify engine mount welds from conversions...... on 2 instances I have refused to do this due to the poor standard of weld that was visiable

Some of the laws sorounding this are wishwashy to say the least, even to the point where "the weld appears to be complete and is of a profesional standard"
Inturpert that gem


Kingy

V8Patrol wrote:
Most cars have a secondary frame for the engine, a K frame as such, this frame is bolted to the cars sub chassis

Its considered 'ok' to weld to the K frame because the risk of injury is very low from an engine breaking free & tumbling down the road whereas the risk from a slider skittling someone due to a weld failure is considered far higher.

With 4x4's the cross member that carries the engine isnt generaly considered as part of the chassis so welding to it is generally accepted as a borderline "ok"
In reality it should also be engineered and I have in the past been asked to certify engine mount welds from conversions...... on 2 instances I have refused to do this due to the poor standard of weld that was visiable

Some of the laws sorounding this are wishwashy to say the least, even to the point where "the weld appears to be complete and is of a profesional standard"
Inturpert that gem


Kingy

ok so can you explain how this relates to say a fj40 chassi for engine mounts and box mounts .. as its a double C section chassi

Suzuki buillders have a shithouse welding technique.. weld and what spatter? meh paint over it..

My welds are 10x betterer..

Same goes for Lux chassis.. Silly Japs.

yeh i knew about the k frames and stuff i was mainly thinkin of 4wd type chassis were an engine mounts directly to the chassis i should have made my post clearer also what about when the chassis is actually being made does it go through some sort of process after all the different mounts and what not have been welded on?

the biggest drama with welding to a chassis is that you are preventing it doing what it needs to do..flex

if you are welding 10-12mm plates on there the chassis is still flexible all the way up to that plate where it becomes stiff..this is where the chassis will begin to crack..

the other important part is due to the thickness difference in the material if you were welding 10-12mm plate on their it is very easy to heat the parent material (chassis) too much while trying to be hot enough to weld the 12mm that you can in fact burn away the original steel on the chassis leaving sweet f@#k all holding the plates and your chassis together, result...snap

the correct way to weld any sort of plates onto a chassis is to make a curved end style plate similar to this <> however ideally the angle should be a slight curve as opposed to straight..this introduces the strength of the plate gradually

the plate thickness should also be fairly close in size to the thickness of the chassis..realistically 5-6mm is the thickest you should ever weld on there

the difference between welding where the engine is and welding slider mounts onto the chassis is the placement of the mounts..obviously the chassis flexes more in the middle meaning welds in the middle of the chassis are more prone to cracking due to the greater twisting motion

i have never, and will never weld mounts onto a chassis for road going cars for sliders..

dave

ok thanks mate

so what about at the very start of the chassis??? like where you would bolt the bull bar too. i am going to need to weld something on the inside of my chassis soon(nuts or plates with taped holes or nuts welded on the back)

Wambat wrote:so what about at the very start of the chassis??? like where you would bolt the bull bar too. i am going to need to weld something on the inside of my chassis soon(nuts or plates with taped holes or nuts welded on the back)

Usually you would use a plate with nuts welded to it and a wire to manouvour it to the right spot.

Cris

finding the right spot isnt going to be hard at all, its only got 3 inchs of room to play with so it will have to go some were there and its shallow enough to move around with your hands,

I don't know what the law is etc on this but I'm in QLD and I guess your wanting to weld in some little plates to simply have the bolts something decent to hold onto for the sliders.

I guess it would be ok, from a dept of transport view point.

As I've extended the chassis on 4-5 HR work trucks, this was before they were rego'd, and the dealership said to simply extend them to the bosses where I work, these trucks transport around 5+ tons of stuff.

All the trucks have been rego'd for a year plus now and nothing has been said to me about the welds and I haven't heard of any problems about getting all the trucks rego'd either, 1 of them has been slightly rear ended and everything was fine and still nothing said about it.

The welds I did were all vertical, and grind an angle to the side and did around 6 beads to make sure the gap was filled and the overall weld will hold. weather that's against the law etc I don't know but nothing has been said to me about it and I'd be the first to know if something wasn't right as I did the work and these days they chase after the person who did the job or work and screw them over not the company etc.

all the Hino HR trucks chassis aren't welded but riveted together, I guess due to shear forces, and would allow the chassis not to flex (flexing is bad it'll cause cracks) but the rails to slide forwards/backwards slightly, the rivets are 1, 1 1/2 inch thick and you'd have 2 rivets for each centre rail with 20mm thick steel shaped into a C they aren't boxed chassis.

The reason why Hino had no brand new 2009 extended tray trucks was that none had been made yet and it would have been a 6 to 12 month wait to get them shipped in from Japan and the company didn't want to wait that long, I suppose money might have came into it but when your buying 5-6 trucks in the 1 hit you'd get a good discount.

also hot rod chassis are welded up and you use K, X and X-H frames to stop torque flex from the motor, cracking the chassis but the members aren't in the centre of the rail length but slightly forward and behind the motor otherwise the rails will just flex around the centre point.

so if the rails are 3 meters you'd start the K member at 1.2meters from the front of the rails.


I suppose another solution is to use current mounting points and use longer bolts etc or use the body to mount from and that way you don't have to do anything with the chassis at all, the sliders I have are bolted onto the body and not bolted to the chassis at all.

zagan wrote:I suppose another solution is to use current mounting points and use longer bolts etc or use the body to mount from and that way you don't have to do anything with the chassis at all, the sliders I have are bolted onto the body and not bolted to the chassis at all.

I would expect the body to get a bit messed up at the slider mount point the first time it gets the full weight of the rig on it.

I would expect the body to get a bit messed up at the slider mount point the first time it gets the full weight of the rig on it.

Body bend...Never haha

mount to the chassis,i would recommend welding but get someone who knows what they are doing to help you. far stronger than bolting around chassis

PM brooksy from here he knows his stuff and is in SE QLD.

Most of us over the years have done stuff thats legal. Doesnt make it ok though.
Welds do fail, esp vertical downs..
There has been a few fatal accidents where forensics trace failures back to chassis weld.

Do you want it to be you or your family?

Bazzle

How do places get away with chassis extensions, where the wheel base is increased.

One would think that would be the place of most stress in regards to chassis flex.

You will find when truck chassis are extended they usually roll the axle back or forwards on the standard chassis and add to the rear after the axle if need be. Where a section of chassis is added, it is normally sleeved with a inner rail that extends past the joint a few hundred millimeters.

In the case of Victoria a report is provided by a VASS signatory that is provided to vicroads on registration.

A guy i used to work for had his brand new HINO extended.

They did this by cutting the chassis(C shape about 6mm thick) virtually in the middle, welding in a section, and then over the top of the extenshion the slid another C section that appeared to be a snug fit, and secured it with about 8 16mm bolts.

I dont know if this is dodgy, but the extended wheel base was a requirement of purchase and organised by the dealer etc. So i would imagine its an acceptable practise.