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Mikey_mike 09-14-2004 06:03 PM

Mandrel bender
Hello all,

I would like to know if any of you have the proper definition for a mandrel bender? I have been looking for a while now and i thought i would ask.


302 Z28 09-14-2004 07:04 PM

A mandrel is drawn through the inside of the pipe to form curves, this keeps the outer walls of the pipe from scrunching down in tight bends. The bend of choice when speaking of exhaust.


Mikey_mike 09-15-2004 03:30 AM

Thanx Vince,

What does the piece thats drawn through the tube looks like? I guess it depends on the bender? Someone said like a ball?

DirtyDaveIrving 01-02-2005 10:11 AM

Definition: Mandrel Bender
Mandrel bending is when a set of balls, called a mandrel, is inserted into the pipe during bending. These balls are positioned and pulled through the pipe so that the bends are not deformed and maintain a close to perfect shape throughout the length of the bend. The pro’s are that the tube can be bent on a much tighter radius and still flow well due to the pipe being round and not collapsed. The machinery is expensive for a good quality CNC mandrel bender with the appropriate tooling.

BillyShope 01-02-2005 06:36 PM

A mandrel bend can be made on most benders if you want to go to the trouble of attaching a ball to a rod which is inserted into one end of the tube. Remember, the tube is being bent at only one spot and that spot is usually a constant distance from one end of the tube. The ball isn't pulled through the tube to make the bend. It's merely sitting there, at the point where the tube is being bent, and preventing the tube from collapsing.

Beenaway2long 01-03-2005 10:40 AM

I'm coming to Orlando in February. Any good Rodding museums around?

(Sorry about the thread rob- back to the mandrel bends)


cboy 01-03-2005 12:10 PM


Originally posted by BillyShope
A mandrel bend can be made on most benders if you want to go to the trouble of attaching a ball to a rod which is inserted into one end of the tube.
What's the ball made of? And doesn't it get pinched in there pretty tight once you make the bend? How do you keep it from getting stuck in there for good? Is it something a novice would want to try while using a Harbor Freight or similar type pipe bender - which is the wrong size for bending tube?

Dewey 01-03-2005 12:26 PM

Here is a video if an 'economy' (they conveniently leave off the price - when they say "call us for prices" that it marketingese for "Our widget is so stinking expensive we are ashamed to publish it!")mandrel bender. Note the long tool bed - this is to capture the mandrel inside the pipe that sits at the point of the bend thanks to the rod anchored at the far end of the bed. Ball is tool steel.

bullheimer 01-10-2005 01:11 PM

not sure what a mandrel is, if it's balls it's balls. as far as i am concerned tho, a mandrel bend in round thru the whole length of the bend. i dont know what muffler shops use, but in the electrical trade, our pipe benders by code, have to leave the inside diameter the same as unbent pipe. my bender here in the shop is just par for the course, you can find them at Greenlee's tool site, whatever that is. you can try but it might not work. i also have a bender from G-B which is gardnerbender. i have the mini-egor hydraulic bender. go figure, ive never used it for car exhaust.

try this:

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