4 link bars
 

I have a Heidt rear 4 link in my 67 Nova.

I'm changing the 4 link bars to 1.25" diameter tubing and adding johnny joint on one end.

1.25" tubing comes in various wall thickness. 5/16" wall is just a little too big ID to drill and tap 3/4" NF threads. I'm looking at the weld in inserts. Drill the tube and weld the insert in.

Question. The inserts are 1" diameter. When I drill the tube it will leave the wall thickness at .125" for the length of the insert Will that compromise the strength of the tube right at the end?

I can also get heavier wall tube but will that be too much weigth?

why not just use .120" wall ChroMo

stiffer than DOM and has a far better fatigue life.

Don't have a good local source for chrome moly and more importantly a welder that can weld and heat treat correctly. I work for a company that stocks a huge amount of steel of all types so I can get the 1.25" DOM dirt cheap.

Anyone else on the weakening issue?

1.25" by .120 wall DOM is more then strong enough.

Also, you can get the 4130 and NOT treat it, no problem. Just use ER80s-D2 and not ER70...

The weak link on the link... will be the joint and not the DOM. If you are concerned utilize two small "plug" welds when you weld the bungs in. Just be sure to use 4130 bungs, if you use cold rolled steel bungs you can pull threads, but a 4130 bung will have to have a material failure post HAZ zone before threads will fail.

Just for reference, Most Off-Road links... TT on down only use .120 wall tube.

Jason

Thanks for the help. Can you lead me to source for the for 4130 weld in bungs?

Thanks again.

rodendsupply.com

1 800 284 2902

thanks
Jason

Thanks,