Proper Half Shaft Lengthening Methods

[drivetrainUW-Platt]

We just got a quote to have our half shafts custom made with the correct splines and if they could match the Honda spline they were going to be between $150 to 200 each, way out of our budget.
I would like to know if the stock shafts can be safely cut, sleeved, heat treated and balanced. It appears 4130 or 4340 is a popular driveshaft material so would a tube of that cut the length and welded work? I have seen where teams v-mouth the ends so that they can get more weld.
One other options, any teams wish to share where they get there shafts done for cheap/free.
Really hoping to get the drivetrain completed this next week so any help would be greatly appreciated.

[drivetrainUW-Platt]

We just got a quote to have our half shafts custom made with the correct splines and if they could match the Honda spline they were going to be between $150 to 200 each, way out of our budget.
I would like to know if the stock shafts can be safely cut, sleeved, heat treated and balanced. It appears 4130 or 4340 is a popular driveshaft material so would a tube of that cut the length and welded work? I have seen where teams v-mouth the ends so that they can get more weld.
One other options, any teams wish to share where they get there shafts done for cheap/free.
Really hoping to get the drivetrain completed this next week so any help would be greatly appreciated.

[Cement Legs]

I think the real issue here is that driveshafts are simply expensive. We shopped around and with this component you really are gonna get what you pay for. Cheaper shafts are cheap material, arent gun drilled or heat treated, etc etc. If you can get shafts made for $150 I think you should consider yourself lucky and pay the price. We figured we could have made ours for around $130 each. But compared to the Taylor Race shafts that are time tested and proven at $160 it was a no brainer for us.... call it $130 for the shafts and $30 for piece of mind..... http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Chris Allbee]

I'm with him on this one. We "mysteriously" had axles break all the time from about 2000-2003. About 2-3 set a year sometimes, all while making an impressive 35-40hp :P They were 4130, solid, mildly heat treated, and occasionally welded (properly). A little research and poling around in 2004 led us to the conclusion that 4340 on a high heat treat (minimum RC45-ish) and gun drilled were the way to go. The amount we were quoted to have them made was around $150, so when I heard about the Taylors, like Mr. Legs says, it was a no brainer. Honestly Mike, there are several parts you can afford to save some cash on and go with the cheaper alternative, this isn't one of them. have the team donate some of their beer money and get the parts you need to have a reliable drivetrain. That car isn't going anywhere with broken axles.

[drivetrainUW-Platt]

sounds good guys, I will get a more specific quote and see if they can match the splines, Any idea what the spline dimensions are for a Honda half shaft?

[Jersey Tom]

4340 is the way to go. Nasty to machine, even fully annealed. Not sure if its weldable.

I'd really suggest just getting halfshafts machined from bar stock, rather than trying to do some weldment. You'd definately want to "V" the ends so you can get a good depth of fusion, but even then, your student weld quality is gong to be questionable unless you have someone AWS certified.

I dunno about filler rod selection and if they even have high-carbon filler. I was under the impression filler like ER70 and ER80 has a very low carbon content, so when welding steels of the XX30 type it dilutes the steel you have in your puddle for a more maleable weld that wont just crack.

ER80 only has an as-welded tensile strength of 80ksi IIRC. Hardened 4340 is upwards of 200ksi.