After cutting the aluminum one i realized it was hardened after it was welded so I was not able to weld it back together. So instead of messing around I made this Chromolly driveshaft

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Very nice work

Nice stack of bottle brackets too!

 

nice notepad too!

 

Nice work....

Did you make or purchase the ends? They're nice looking pieces, regardless. Just curious if its your machine work.....Looks like it'll stand up to just about anything you want to throw at it.....

This ought to be one fabulous machine once you're done....

'JustDreamin'

 

I designed the ends and turned them down (roughed them in). Then had our head machinist finish them, I think it is wise to know your limits. This driveshaft spins at engine speed (in front of trans). So it has to be very accurate. The ends are a slight press fit into the tube. Then I welded it all together, next step is to make sure it is balanced

 

It is all of these little things that take SO DAMN LONG.

It should have been a 20 minute job to shorten and weld and I had to make a whole new one.

The only other option was to have a company make a carbon fiber one for like 1500-2000 Way over my budget

 

very nice work
especially with making the ends, etc.

 

I will not know how nice it is until it spins at 7k with 600hp going though it

 

Well whats the advantage? Strength? I know the weight is going to be higher with the chromoly piece. Looks great, love it when people fab up their own stuff.
Phil

 

The advantage is that it'll hold up after he's modified it.

The aluminum shaft is probably heat treated. If you look at most aluminum alloys (wrought or cast) most all of them need a fairly specialized heat treatment process to have any strenght. Take for instance 6061-T6. Great stuff, yield strength is like 40 kpsi (40,000 lbs per sq inch). In non-heat treated form, which is what you'd have if you get a TIG torch (or any welding process for that matter) anywhere near it, the yield strength drops to about 8 kpsi (8,000 lbs per sq inch). That's only an 80% reduction in strength (Yikes). And the process for heat treating aluminum isn't simple or inexpensive, so doing it on a single piece basis is usually pretty pricey. And the ends are likely to be castings anyway, so if we assume they're 356T6 (one of the best casting grades) the yield strength (in heat treated form) is only 30 kpsi.

The Chrome-moly stuff won't suffer the same problems, because its undoubtedly in the annealed condition already, and could easily be heat treated to be significantly stronger. 4130 for example has a 60kpsi yield in annealed (hot rolled) form, 85 kpsi in cold drawn form, and can be heat treated (drawn @ 1000 degrees F) to 133 kpsi yield. I personally would leave it alone, because of the risk of distortion, and wanting to keep the material from being the slightest bit brittle.

So basically, in as welded condition, the chrome-moly is at least twice as strong as a factory shaft in heat treated condition.


Personally, I think his choice of materials is spot on. Yes, it may weigh a bit more. But it won't give up nearly as easily. And if he was really concerned about weight, he would have scallopped the flanges to eliminate a fair bit of metal. But that's also alot of machine work, for not alot of reward. Sure, the reduced weight would be nice, and the higher gee-whiz factor would be great, except that nobody will probably ever see his driveshaft while its in the car.

'JustDreamin'

 

Dreaming u nailed it there, I would have loved to "scallop" the 3 sides. However that would have been far more difficult. Do do it properly I would have had to set up a CNC program which I do not know how to do. Weight is always important, but none the less I am on a budget and am trying to get the car done.

 

You wouldn't have had to do it CNC. You could do it old school with a rotary table and lots of time. Either way, the end result would have been very little change in performance for a fair number of man hours of work. Not worth the investment, especially since there's so much car left to fabricate.

Keep at it, you'll get 'er done and be driving before you know it.

'JustDreamin'

 

Would you make to sell? I was thinking of doing the same thing. It looks great. Are you using any rubber couplers like the stock one.