Technical To drill or not to drill.

... sure they did. Old school JD engine rods, with pistons, nearly 100 years old.

... and still do.

 

Interesting! I stand corrected... What are the newer rods for?

 

Torsion (twisting) forces on an I-beam axle are not as severe as you might think. The majority of the torsion caused by braking is taken up in the leaf springs or wishbones/parallels. Even axles with drilled axle ends like kidcampbell71's are not in any trouble. The calcs show that the web does as little in the torsion stress arena as it does in the bending arena. Again the deformation is a function of the moment of inertia to which the web contributes precious little. Just has to be enuf web left to keep those flanges where they need to be. They do all the heavy lifting (pun intended)..

 

I can tell you one thing for absolute certain; they are for $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$!!

Speed costs. How fast do you want to spend?

 

Hole-ee Hotrods Batman ! Know that we know the hole story, maybe the Batmobile should.....nah, better not......

 

Unless your life in lived in .001 second and you are lightening everything else drilling your axle is for looks. If you like the look drill it. its not a 10 minute job but if it floats your boat its worth the labor.

Here is the thought, my current project was first a land speed car then lived the rest if its life as a dragster. It does not have a drilled axle.

 

I remember going to World of Outlaw sprint races years ago and seeing steering wheels with holes drilled in them to lighten them up. So I guess if your as crazy as Steve Kinser, Doug Wolfgang, and Sammy Swindell I say go for.

 

Damn . Just imagine the sound this thing would make at 100mph plus with no body on it.

 

It would be Whislin' Dixie!

 

Interesting, nobody has claimed they have had one fail that was drilled.

 

They shouldn't!

 

Drill

 

But the twisting force caused by the brakes is transferred to the hairpins, shouldn't apply any force to the center part of the axle.

 

That's cause those people are no longer with us. LOL

 

In the '70s and '80s we used to drill the con-rods and the flywheels both. Light bike light lower end.

 

So, to stir the pot again. No reported failures.

 

I'll agree that the main purpose of drilling an axle on a street driven car is for looks, and it's a look that I like and have on my '31 "A" Hiboy.
I'm guessing, but I suspect the first drilled I beam was on a car used in competition, and that it was just one of many things done to that car to lighten it up to the max. You do reach the point in lightening the car that every little bit added to other little bits adds up to lots of pounds.
Then somebody saw this on the race car, liked the looks of it, and decided to copy it on their street driven car.
There's another factor in this weight reduction no one has mentioned, and that's unsprung weight, which can be a major factor in tire adhesion on uneven surfaces. IMO. the biggest shortcoming of I beam front suspension is unsprung weight, and this drilling des, percentage wise, make a difference in unsprung weight.

 

The engineers say not worry about it.

Armchair quarterbacks say to not do it.

Enough said.

 

I've drilled every axle on every car I've built. Its a personal preference, I like the way it looks. I have a Superbell cast axle on my '32 and Posies called Superbell and asked if it could be drilled. Their answer was 3/4" holes 1 1/2" on center is the correct pattern with no reduction in strength of the axle. That is good enough for me. I don't paint my wheels red either, anything but.

 

I hand drilled a 47-54 Chevy 1/2 ton truck axle for my ‘56 Chevy when contemplating a Gasser. Used a 1/2” drill with various size drill bits and step drill bits as well. Went to 3/4” diameter from center of web with 3/4” side to side width. I used a 4x4 post strapped to tailgate of my Chevy pickup, strapped the axle down on the 4x4. Started from center of web outward to the ends. Best I remember, (2016) it took 6-8 hrs, Looked great when finished, I was completely tired and sore. Did not build Gasser and if there is a next time I will have a heavy duty drill press.

 

The trick tool is a vertical mill, with a nice end mill.

You can do an axle in about an hour.

 

That last shot of the split bones confuses me. You drill holes to get rid of some weight but fill those holes with tubing to strengthen the bones? I'm sure that there would be a net gain in weight not a reduction...

 

And I am sure you are correct, that being said, I shot the photographs, only to show what the car owner had done, the car isn't mine.

 

I say drill.

 

He didn't say why he did it. It's more of a look then a function. Personally I like it.

 

Drilled by a friend of mine. I like the extra holes, less wind resistance!


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While I'm in favor of holes, I Don't understand why you would drill holes in brake backing plates. Seems that would be detrimental for stopping when it rains.

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My first thought...dead men tell no tales

 

I'm an engineer and I agree. We tend to be very careful about what we put holes in and things like edge-distance comes up, read up on it.

 

Lots of hole threads on here. Search function.