[5vzfehilux]

Hi,

I made this as a sample u-bracket for some 4x4 rock sliders using a stick welder. 8mm mild steel welded with E6013 at 100 amps. I flap disc'd at the welded edges but as this was a test, I didn't bother with the rest as you can see. These are the brackets that wrap around the chassis rail of a 4x4 and then you drill a bolt hole and bolt across the top of the chassis if hosing wiring etc permits. In my case most will have to be thru the middle to go with holes in the chassis that are already there from factory and because of fuel and brake hosing across the top.

I have to make 6 of them for real. But I don't know a quick way to fit up and clamp the job etc to get them done without melting my small brain.

Anyway, the first joint to weld being only two plates to join is pretty straightforward as I can clamp that up easy with a right angle mitre clamp thing. That allows me to weld the outside corner first. To weld the inside corner, I C-clamped the bottom plate to the welding bench and had a big right angle magnet on the outside of the vertical plate face, to stop any pulling when welding the fillet weld. This worked ok.

But getting things set for the second joint to add the second 'upright' is where the fun starts. The width of this bracket is only about 63mm so that means my mitre clamps won't fit inside, to allow the whole thing to be held the same way as the first joint. I tried instead with a big magnet to hold the second plate on, but the arc did not like that at all - it jumped around blew out etc. So I ended up getting some 5mm angle scrap and clamping one face of the angle to the bottom plate and clamping the vertical face of the angle to the vertical plate. That sort of worked ok - a bit fiddly to get just right and very easy to mis-fit where as you can see the vertical faces didn't end up perfectly mirroring each other - one has a slight kink. It did at least allow it to stay square though while I welded the outside corner.

So when I came to the inside corner, now things are pretty tight for room. I tried the same method as for the first joint (clamp bottom plate to bench and magnet on the outside of the vertical plate) but it still actually pulled in a mm at the top of the bracket. It stayed at the right width at the bottom of the joint though. Test fitting on the car this actually gave a nice slide-on tight fit but it's obviously not ideal.

So any tips on how to clamp up for the second vertical would be great - mainly around saving time and giving me a repeatable method cos the way I've gone so far, it will take me a long time and no guarantee of everything square at the end. Main things are how to set up the second vertical to be square and how to stop it pulling in at the top.

Thanks,

[cj737]

With an open joint for your uprights (the intersection of the bottom flat plate to the upright) I really don't think you need to weld the inside corner. At least, I wouldn't feel the need if it were mine. This is provided you weld a full bead to fill the open corner.

The other added benefit of this is that the upright ends will tend to pull apart, which when bolted through will pull back together. That should hold very well if your welded corners are good. Can you run a 7018 rod? Use the 6013 for the root then a cover pass with 7018 (or equivalent in your country).

[tweake]

simple way to clamp it is to make a packer fit in-between thats the right size. camp the sides to that.

as you really wan the mount to sit hard on the bottom of the chassis i would not recommend welding on the inside, otherwise the chassis will sit on the welds.
a simple root pass will do. 6011 root 6013 cap, or if you want to go fancy 7016 root 7018 cap.

8mm kinda big for mounts. i suspect you probably only have 3mm chassis.
putting a bolt through the centre is not great without crush tube in the chassis. you do not want the bolt pushing on the edge of the chassis steel. decent impacts could deform the hole.
i can't recall how the pro's do it at the mo.

keep in mind if its a road going 4wd, its really easy to get it above max weight due to the weight of all the bar work.