(i think this is a drag question more than fab but if not i will move it)

i looked at an (old) exhaust bender/swedger/expander tonight fully loaded with tooling. the exhaust bending abilities dont terribly impress me, but i brought along a piece of 1-3/4 .140" wall (yes .140) and this was the result. this is worst case scenario, maxed the travel and the die sorta lodged so the corners made a hair more indent than i expect on a 90* bend.

i know this would be fine in the old days,, but would tech send you home for this in a 10 second car nowadays? which type of racing sanctioning bodies tend to be the strictest?


***my only question is if the tube will pass or fail, no guessing, need facts. please hold rants about why i should buy a $25k machine..





(last shot is of the outer radius at apex. there is no deformation.)

thanks for your time.

 

pm camp1320 for the absolute correct answer. For some odd reason he has all the answers about passing tech inspections for nhra.

 

thanks for the reply ill keep that in mind. i let the machine pass though. kinda glad i did.

 

Mike you can buy a number of different benders for less than 2000.00 dollars that are used by many of the chassis builders. I myself have a hossfeld a(with Hyd) which will cost you more but there is a nice bender made by mitler bros that is a rotary draw style that is really nice and I beleive the basic machine is about 3000.00 I haven't looked lately but the only thing I didn't care for was the large radius of the dies bu they may have changed that. There are allot of shops that use the jd squared benders. The jd stuff is similar to the hossfeld as it works on a compression principle rather than the draw type. Either type will work for race car applications. As far as that bend goes it would depend on who looked at the car and how obvious or visible it would be. If the bend was on a car that needed to be certified then I would say no. And the other thing is that that bender wouldn't bend anything thinner than the material you tried.

bob kasper
kasper fabrication & machine
609-851-2810

 

thanks for the info bob. the reason i was interested was because of the expanding and swedging as well as a shitload of dies, fullshoes and halfshoes that came with it all in good shape. the machine went for $1500 but as i said, id decided against it.

im familiar with all those benders u mention and have actually built 2 rotary draw machines here. turning dies is very time consuming. that machine was tempting to fill in temporarily, and to just whip out crappy exhaust.

if i can ever find the time again the hydraulic bender im going to build will utilize a hydraulic ram that pushes a sawtooth rack past a pinion gear which is keyed to the center shaft that dies will be keyed to, supported by big transmission bearings ive been collecting. ive gotten acceptable results with rotary draw and one pressure die (half shoe) but i would like to try thin wall material maybe using inserts or sandbags inside the tube, maybe full on wiper and pressure dies if i can think of a feasible way to machine them.. anyways..

"..if i just had the time."