Cold bending

[Knuckelhead]

I’m doing the build up of my WJ/high steer axle conversion and want to know if cold bending will work on a Tera Flex adjustable track arm. If I remove the bend located at the differential and shorten/rethread the LH part of the arm, it will work perfectly. I don’t want to use spherical ends, build a new arm and change the frame mount… TIA

[zachv]

It should be fine if you can get the bend out that you need. Sometimes the piece will have a "memory" of the bend that will never come out. Do you need it straight or just a few less degrees on the bend?

[Knuckelhead]

Probably closer to 7 degrees of bending needed, close to straight. I’ll be looking for a shop with a press tomorrow…

[StealthTJ]

Originally posted by Knuckelhead:
Probably closer to 7 degrees of bending needed, close to straight. I’ll be looking for a shop with a press tomorrow… I wouldn't cold bend it, not a part as important as that.
If you're using a shop that has a press, they'll have a torch to heat it.
The metal will thank you ;)


Fred

[StealthTJ]

BTW, are you talking about the Tera track bar or their steering arm.
If it's the track bar, what works really well (for the WJ conversion) is the RE "heavy duty" track bar and the drop bracket (weld it to the frame don't drill through and bolt it). You'll have to cut the track bar to length but that's an easy job. Their drop bracket along with the WJ Pitman arm aligns everything just about perfectly.


Fred

[zachv]

Originally posted by StealthTJ:
I wouldn't cold bend it, not a part as important as that.
If you're using a shop that has a press, they'll have a torch to heat it.
The metal will thank you ;)


Fred Using the torch will cause more damage than cold working.

[edudley]

Zach you the expert here but wouldn't you run the risk of cracking the material if you do it cold. At least worm it is more maluable.

[Knuckelhead]

I have an acetylene torch but, I was thinking along the same lines as Zach. I don't believe the Tera track arm is hardened and I'm only bending it about 7 degrees...

[zachv]

I have always been taught that heating a material such as mild steel will cause the molecules to deform and cause a weak spot. IMO, heating before bending will allow the tube to crush instead of bend. I am definitely not an expert in this area--just going off of what I have been taught and have experienced. I have absolutely used heat to bend things before, but I believe that cold working is generally accepted as the stronger way to manipulate steel.

Overall, if you need something almost straight, why not cut the bend out completely and weld in a straight piece of tube?

[kwrangln]

Were it me, I'd just cold bend it, easy enough in a press. In fact a guy at work is waiting for me to get a chance to do the same for his front trac bar on his rubi.

The heat method would work just fine if a press wasn't available. From my experience with metal work and all the classes, a crystaline structural change in the metal wont be a concern untill its heated to just below its melting point. Keeping that in mind, heating to a cherry red color (bright yellow to white will be just below or right at melting point) will allow you to bend it with little more than arm strength, but not be hot enough to affect things.

Changes in the crystaline structure of common steels is usually associated with the heat affected zone of a weld, where the weld area itself is heated to the melting point (allowing fusion between the filler metal and base metal) and the area immediatly surrounding it is heated to just below the melting point allowing the lil bits that make up the steel to move around and get out of line. Think of the crystaline makeup of steel like a handful of wooden coffee stirrers. With em all lined up you cant break em, throw em in a pile on the ground so they are all mixed up, pick up as much of the pile as you can, and you can probably break a bunch of em easily. The only way to realign the bits in the steel is through a heating and cooling cycle, or heating and work cycle.

All laymans terms, I dont do much of the book type terminology and whatnot, but it is what it is.

Hope this helps a bit, or at least makes things as clear as mud.

[kwrangln]

Just reread the origional post. Since the trac bar is likely tube, if your going to use heat, pack it with sand before heating to keep from deforming the tube when you bend it. Thread in one end, hold the tube verticle in a vice right below where you want it to bend and fill with dry sand to a point well above the area you will be heating. When using this method, dont have both ends of the tube capped, plugged etc without a breathing hole as the sand will have moisture and buildup pressure inside the tube.

If it is in fact a solid bar tapped on each end for the fittings, then disreguard and bend away.

I'd still do it cold, nice and slow. Just some thoughts.

[Knuckelhead]

Got it done. Cold bent it on a 20 ton press. If you looked close enough you could see the marks from bending it on the original jig that was used when it was made (its solid, not hollow). Then shortened the arm and rethreaded it in a lathe. Thanx for the advice. smile.gif
Now all I have to do is swap the ARB, Warn hubs and axles out of the low pinion, weld on the sway bar brackets, space the calipers, grind some more metal, paint, ect..ect…ect :D

[James]

Originally posted by Knuckelhead:
Got it done. Cold bent it on a 20 ton press. If you looked close enough you can see the marks from bending it on the original jig that was used when it was made I can't see a thing! Where's the pics? :D

[Knuckelhead]

Still in the camera. :D And I’m the illiterate one, remember? If anyone wants to come by and take pic’s their welcome….
The track bar did turn out a whole lot better than I expected. I was even able to tweak the frame end of the bar for the greater axle drop compared to compression, I even straightened the other (right-hand) end/half of the bar. Now I get to fine tune the draglink ;) . Piece of cake IMO…