Best method to ensure a square cut on a mandrel bend?

If square is the right term....I making some cuts on exhaust j-bends. I would like the cuts to be square so the pieces will mate and swivel as seamlessly as possible.

 

I have found using a hose clamp will make a fairly square cut mark.

 

Yep....hose clamp works for me too. Position the screw in portion at the bottom and slice away.

 

Bandsaw for me.

 

drink as much as possible, that way you have something to blame your misguided cut on.... - the saw is family

 

Here are a few hints. Lots of other photos and a few simple tricks to make it work.

http://www.jefflilly.com/fabrication/header-fabrication
http://www.jefflilly.com/fabrication/exhaust-system

 

Some excellent tips there - I like the use of a pipe cutter to score a line and also making a tack welding clamp from hose clips and an offcut of tubing. I use a piece of angle iron and G clamps for joining straight lengths.

 

**** you Barett. Nobody likes you.

That's good stuff! I read about that header mock up kit in Car Craft. It's on the list! Thank you very much.

 

If you have a centering square, that will make a nice line for the bandsaw....

 

The cuts Im trying to make are in the bends

 

Slideing the right size O-ring over the tube will get you real close.

 

Sharp tubing cutter with cutting wheels in all three positions (no rollers)...

 

Fabbing the exhaust for my 50 Pontiac I came up with this: I draw the offsets or curves I need (I use CorelDraw but hand drawn is fine) and mark the bends with this little fixture. Cut the tubing and touch up the cut if necessary on a disc sander ( I built a 12" sander for this, but a combo belt/disc sander like a Craftsman works too) Tack it up carefully and make whatever welds you can on the bench. Just takes time.

 

I do tons of them with a 7/8"-2 1/8" Ridgid brand tubing cutter.

 

Works good and also leaves a slight kerf to give room for a weld bead.
But if TIG welding Bandsaw gives a squarer end. Also if using a tubing cutter in a bend usually you can't completely rotate tha tool cause it hits the leg of the tube. BUCKD

 

I don't have a band saw yet, but that's on the list, too. I ordered a chain cutter last night, that might do the trick.

 

There are a couple of angles I can't get into on the average U-bend, but not many. I try to make my first cuts kinda generous, then trim back from there to get my finished angle. My cutter came from a local pawn shop for about twenty bucks and has served me well for many years now.

 

I've done alot of mandrel exhaust- both my 55 & my 32 use mandrel U bends cut to fit.
I don't bother w/ a band saw.
I use an o-ring to mark & then cut w/ a chop saw w/ laser sight. Perfect square cuts every time.