How much force to bend

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I have a gokart with a solid aluminum axle 45" long.  Roughly 12" between bearing and wheel hub on either side.  It has a 1/4" keyway on it that is cut halfway down one side half way, and then continues down the rest of the shaft on the opposite side.Reason I ask, I think the axle is bend between where the bearing supports it and the wheel hub is.  Wonder how much more force a steel shaft of the same dimensions could take?Perhaps chromoly?I was hoping one of you with solidworks or something like that might be able to calculate it..... or perhaps point me to a place where I can calculate it.Thanks in advance!The Lord has declared, "This is my work and my glory--to bring to pass the immortality and eternal life of man"  Moses 1:39Link: My name is John, and I am a member of The Church of Jesus Christ of Latter-Day Saints.-- ColdCreekWorks.com --
Reply:Ditch the solid aluminum axle and go with a hollow steel one.  They aren't too expensive.  Less than $100, but more than $50.My name's not Jim....
Reply:Or chromoly tube one.Aluminum and axles don't belong together.
Reply:Originally Posted by BoostinjdmDitch the solid aluminum axle and go with a hollow steel one.  They aren't too expensive.  Less than $100, but more than $50.
Reply:Check with a magnet.... it is highly unlikely to be aluminum.  If you can set the shaft on some wooden blocks and then hit the high spot with a soft face hammer you likely can take most of it out.  Otherwise you will need some sort of press so you can push accurately.  if it is a one inch shaft I doubt you will have to push more than 500 pounds with a press.
Reply:Am I right in thinking that in some situations, a section of heavy wall tubing is actually stronger than a solid bar stock of the same O.D.?
Reply:Originally Posted by lotechmanCheck with a magnet.... it is highly unlikely to be aluminum.  If you can set the shaft on some wooden blocks and then hit the high spot with a soft face hammer you likely can take most of it out.  Otherwise you will need some sort of press so you can push accurately.  if it is a one inch shaft I doubt you will have to push more than 500 pounds with a press.
Reply:Originally Posted by patkenbarAm I right in thinking that in some situations, a section of heavy wall tubing is actually stronger than a solid bar stock of the same O.D.?
Reply:Tube is stronger or rather stiffer than the same amount of material formed in a solid bar.  If you have a press then you can measure the deflection of the shaft when it is turned in vee blocks set in the press.  If say the deflection of the bend in the axle is 1/2 inch then set the axle high side up and press down 1/2 inch.  Check it.  Likely you will have to bend it in the press 3/4 inch or more to get it to start straightening.   I cannot see an aluminum axle being very practical for a goKart unless you are not going to prang it up against anyone or anything.  I am wondering if the aluminum axle is a heat treated alloy such as 7000 series?   In any case you can straighten it and consider replacing it with a much larger diameter tube however that will require different bearings and other adaptions for brake disc and drive sprocket.
Reply:Originally Posted by patkenbarAm I right in thinking that in some situations, a section of heavy wall tubing is actually stronger than a solid bar stock of the same O.D.?
Reply:Originally Posted by patkenbarAm I right in thinking that in some situations, a section of heavy wall tubing is actually stronger than a solid bar stock of the same O.D.?
Reply:Originally Posted by MikeGyverIf it's the same material and everything else is the same than the solid will have a higher strength because there's more metal (it's essentially a thicker wall).
Reply:There are a few different questions going on here, what you have to do is ask the question you really want answered.Do you care about stiffness, strength, or something elseNow to you want to compare by identical weight, identical shape/size, or otherIf you calculate deflection (stiffness) of a solid bar versus a hollow bar of the same OD, the solid will generally deflect less, exceptions occur when the bar gets really big, and the load is relativley small and you take into account the weight of the shaft.  Same deal for a cantilever, which is closer to a cart axle.  There is also torsion to take into account.What it boils down to is that in a strength vs mass comparison, hollow wins.  If you look at strength vs OD, solid winsLast edited by Fred s; 07-23-2012 at 11:57 AM.Reason: spellingExperience is something you get right after you need it
Reply:Originally Posted by Fred sThere are a few different questions going on here, what you have to do is ask the question you really want answered.Do you care about stiffness, strength, or something elseNow to you want to compare by identical weight, identical shape/size, or otherIf you calculate deflection (stiffness) of a solid bar versus a hollow bar of the same OD, the solid will generally deflect less, exceptions occur when the bar gets really big, and the load is relativley small and you take into account the weight of the shaft.  Same deal for a cantilever, which is closer to a cart axle.  There is also torsion to take into account.What it boils down to is that in a strength vs mass comparison, hollow wins.  If you look at strength vs OD, solid wins
Reply:Originally Posted by KelvinThat makes sense but then why is a fluted rifle barrel stiffer than a solid (unfluted) rifle barrel?
Reply:Originally Posted by KelvinThat makes sense but then why is a fluted rifle barrel stiffer than a solid (unfluted) rifle barrel?
Reply:Originally Posted by BoostinjdmMore surface area and corners.
Reply:Originally Posted by KelvinThat makes sense but then why is a fluted rifle barrel stiffer than a solid (unfluted) rifle barrel?
Reply:Originally Posted by OldendumA fluted barrel of the same weight as an unfluted barrel would be stiffer because of the larger diameter.  Simply adding flutes shouldn't make a barrel stiffer.
Reply:I am no gun expert by any means but I thought you would get the performance of a bull barrel out of a barrel that weighs alot less. Im strictly a bowhunter, even tho ive been around guns my whole life so just my thoughts. I thought the intention of a bull barrel was to take the whip out of it, meaning with a fluted barrel you would get the stiffness of the bull due to the square corners, without all the weight. Just my thoughts, never studied that deep into it, until now.I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Originally Posted by patkenbarAm I right in thinking that in some situations, a section of heavy wall tubing is actually stronger than a solid bar stock of the same O.D.?
Reply:+1 dsergison... you posted while I was digging up a bookmark to the deflection calculator. It doesn't look like weight reduction was even part of the design/plan. If it were me I'd grab a length of 4130 shafting and have my key ways machined into the locations required and call it good. Most any shop could turn this around quick and cheap. For the time being I'd straighten the shaft you have and have some fun. If nothing else you'll learn the art of press straightening. Here's a simple deflection calculator:http://www.wa4dsy.com/robot/bending
Reply:Aluminum doesn't like cyclic bending. Don't be surprised if you axle lets go while you are driving.