Chassis A-frame mods - weld vs drill and screw

[Curryhouse]

I have a couple of mods on my list of things to do that require fitment of a couple of brackets and angle iron rails to the A-frame. I don't have a welder and intend to drill and screw (10-12G) the fittings. Could such drilled holes create a weak spot that may lead to cracking? Would welding be a better option to minimise risk of weakening the A-frame?

 

[Soaring]

I don't like the idea of welding or screwing to the A frame, and I'm sure both warranty and it insurance could be affected. U bolts are an alternative that avoids either, would these work in your application? Reversible too for resale.

 

[achjimmy]

@Curryhouse in theory anything you do to the a frame can potentially weaken it. if you look at the mark a u bolt leaves on the corners of the tube after install that has the oppertunity to become what is referred to as a "stress raiser point " and for an example would be a "no go" in aircraft or racecars. follow proper guidelines and common practices and you will be fine. There will be a lot "redundancy " built into the engineering of a Jayco drawbar. After all how many Jayco drawbars have we heard of failing?

Don't weld across or ideally screw anything to the topside of the drawbar tube. The sides are fine for screwing, and welding but you still want somebody that can weld properely. screws ideally keep to the centre of the tube. Additionally you have issues with wires needing to be removed from the drawbar beforehand if welding, which can be a pain.

As @Soaring said u bolts are ideal in many cirmstances on the drawbar.

Below is how I did my gas bottle relocation with u bolts, but also welded on the inner jockey wheel clamp. But you'll notice I bent the upper support to cross the drawbar tube and only welded it on the opposite corners not across.

The ubolts are solid as and offer no deflection.

 

[Curryhouse]

I don't like the idea of welding or screwing to the A frame, and I'm sure both warranty and it insurance could be affected. U bolts are an alternative that avoids either, would these work in your application? Reversible too for resale.

. Thanks @Soaring. Both are basic mods; one is a bracket holding a new pole holder. U bolts could likely be used for this one. The second was fitting a piece of wire mesh between the A-frame arms and in front of the gas cylinders. Thought it may be handy for a carrying wet hose. I was going to fix a small piece of angle iron on the inside of each arm and have the mesh sit on top. Will think more about the idea now.

 

[Curryhouse]

Thanks Jim. Good advice. Will look again at the mods to come up with a different plan of attack.

 

[Soaring]

. Thanks @Soaring. Both are basic mods; one is a bracket holding a new pole holder. U bolts could likely be used for this one. The second was fitting a piece of wire mesh between the A-frame arms and in front of the gas cylinders. Thought it may be handy for a carrying wet hose. I was going to fix a small piece of angle iron on the inside of each arm and have the mesh sit on top. Will think more about the idea now.

Cheers @Curryhouse . Another alternative to the u bolts are the worm screw type hose clamps. You can get large ones from places like Blackwoods that are large enough to go right around a drawbar and clamp up tight. This might work to hold your mesh in place.

 

[17triton]

I didn't like the idea of welding either to my drawbar. Like the others said about weekening and resale. This is my bike rack mod I used plate steel and hi tensile bolts to secure it. It's a lt heavier than what you would require for a basket but you could use the same principle.

http://www.expandasdownunder.com/threads/17tritons-17-56-1.2759/page-2#post-40663

 

[Curryhouse]

Cheers @Curryhouse . Another alternative to the u bolts are the worm screw type hose clamps. You can get large ones from places like Blackwoods that are large enough to go right around a drawbar and clamp up tight. This might work to hold your mesh in place.

That was an option that crossed my mind however wasn't sure where I could get the larger size. Luckily there is a nearby Blackwoods - I need to pay them a visit. Thanks for the suggestion.

Hi @Triton - that's a substantial bike rack and a clever one at that. Pleased for you that it got design approval

 

[Drover]

I used threaded rod and made some plates to clamp over the rail as I couldn't find the U bolts I wanted, the ones I did find were exceedingly costly, used the same idea to clamp my stone guard on, drilled a plate pushed threaded rod into hole and welded it up, then just used a nut on the other end with a plate.

 

[homerJ]

I have a couple of mods on my list of things to do that require fitment of a couple of brackets and angle iron rails to the A-frame. I don't have a welder and intend to drill and screw (10-12G) the fittings. Could such drilled holes create a weak spot that may lead to cracking? Would welding be a better option to minimise risk of weakening the A-frame?

Drilled holes generally dont create a weak spot provided they are not too large. (In fact, the TE Cortinas used to crack the front rails and the fix was to wet the area with WD40 to reveal the end of the crack and a small hole drilled to stop it cracking further)

As others have said dont weld if you can help it. If you have to weld along the sides of the drawbar, not across. Also, if you make whatever you are attaching with multiple contact points and it 'sits' on the drawbar the welds are only holding it in place so can be just short runs.

 

[Soaring]

Drilled holes generally dont create a weak spot provided they are not too large. (In fact, the TE Cortinas used to crack the front rails and the fix was to wet the area with WD40 to reveal the end of the crack and a small hole drilled to stop it cracking further)

As others have said dont weld if you can help it. If you have to weld along the sides of the drawbar, not across. Also, if you make whatever you are attaching with multiple contact points and it 'sits' on the drawbar the welds are only holding it in place so can be just short runs.

Drilling a hole can work to arrest crack propagation, however the crack would have started due to an introduced stress concentration point. This is what is trying to be avoided by not messing with the drawbar.
Welding tends to alter the grain structure of the steel, but the end result is similar, an introduced stress concentration point.

 

[ShaneT]

. The second was fitting a piece of wire mesh between the A-frame arms and in front of the gas cylinders. Thought it may be handy for a carrying wet hose. I was going to fix a small piece of angle iron on the inside of each arm and have the mesh sit on top. Will think more about the idea now.

Thats how mine came from factory. That aluminum screen security door stuff welded to angle then 4 tech screws into the chassie.

 

[Curryhouse]

Thats how mine came from factory. That aluminum screen security door stuff welded to angle then 4 tech screws into the chassie.

Thanks @ShaneT . I ended up using a smaller gal mesh, a couple of pieces of angle and two tek screws. Should do the job.

 

[Dove]

I wanted to carry an extra 20lt of fuel for our next trip. I was about to drill holes thru my draw bar to mount the jerry can holder and then I read this thread.

I now have the holder bolted to the frame using a steel backing plate. No holes in the draw bar. I will try to add some pics.

 

[cruza driver]

Neat job @Dove do you have any stone protection so nothing can flick up at the jerry can?

 

[Dove]

No, hopefully as its a steel jerry can stones won't be an issue?