Pipe bending questions

[rbray]

Hi Guys,
I saw a pipe bending rig at Harbor Freight and I have a question.
The machine has a 12 ton hydraulic jack and a set of half-moon shaped bending dies. Will this machine make smooth 'mandrel' type bends?
I need to make a new roll bar for my auto-x racer and I am wonder in this machine will do the job for me.
Thanks,
Roger

[Sonny]

rbray,
happenened to stop by shop this am and check board, while the '12 ton' sounds impressive, it is not a very professional looking bend and will result in small wrinkles on sharp 36 degree or greater bends. covered with foam and vinyl or racers foam surfaced foam tubing it might pass spec for historic type racing, but will not comply with most scca functions and definitely fia type international rules. i would suggest if you must design your own roll cage for semi-prof racing that you contact some of the nascar/arca/grandnational roll cage kit suppliers with your requirement. don't shortcut on this if you are going for safety or looks for sure.

[Dan Heck]

Roger,

Unfortunately, the 'pipe-bender' type tools can't do a good job on tubing. The non-mandrel bent elbows in the typical stock exhaust system are what you'll get with tubing vs. pipe in this type bender. My car's headers were made with a pipe bender instead of a proper mandrel bender and they look pretty crappy. Here's some info on the subject and a semi-inexpensive ["only" $500] option:

http://www.lowbucktools.com/hydbender.html

Dan

[RACER X #99]

Roger, I am not familiar with that type of pipe bender. but I can tell you that the bending shoes must fit exact or you will kink the pipe. I have made lots of roll bars with a hydraulic bender and with a little practice you can to. Just make sure that the bending shoes are a perfect fit for your tubing. Use .120 wall DOM tubing for all your bars 1.75 min.
Cranky ( professional pipe bender)

BTW the bender that Dan reccomended looks pretty good for a home unit.

[Sonny]

roger,
after reading the second post answer, i still suggest you contact csc in minn or someone like them, a full arca kit for professional arca stock cars is less than $300 in kit form and bent on a $20,000 dollar swage/rolling bender that gives nice looking bends. this goes for the structural capability of the cage as well as looks. when bend are made you stress the mild steel and thick thin the wall in the bend area to accomplish this. you will need to assign a cage id number and drill it to allow the tech official to caliper the tube wall. make this convienent for him also. cheapest best route to take, been building cobras/vettes since 1970 and have use this method even in our shops. what about the cage your supplier offers? if he doesn't offer one for liability reasons or whatever, your suspension geometry will probably be so "out" you'll never get a good handling car to begin with.

good luck

[mr bruce]

That Harbor Freight bender is basically a conduit bender. You need a real follow bar bender to bend mild steet tubing.Like the one from Pro-tools,(813-986-9000) A mandrel bender has mandrels that fit inside the tubing, to keep wall thickness consistent.Watch out where you get your tubing too. Lots of the stuff out of Canada wont pass tech because of inconsistent wall thickness.Most racing.series use sonic testers to check roll bar thickness now .What kind of car you got?By the time you buy everything to do a one off project ,you'll probably be way ahead cash wise to buy an already built cage.

[rbray]

Thanks for all the help guys.
I have decided to pass on buying the machine.
I need a new rollbar for my modified Miata that I autocross.
The SCCA requires that any open top car running in a mod class have a rollbar that is above the drivers head. The bar I have now is as high as it can be and still allow the soft top to function.
What I need is a way to bolt up some type of extention before the race and take it of after so I can put the top up.
once again thanks for all of your help.
Roger

[Dan Heck]

Miata rollbar, you say? Seen these?

http://www.bethania-garage.com/


Dan