The Jalopy Journal
Discussion in 'Traditional Hot Rods' started by reekie6, Oct 17, 2019.
You see how "right" holes look on this one or that one when built with some attitude.
Never drill any axle as it weakens them. Think about it, you're at the red light and launch hard and the axles can't handle the torque grenading. Now your differential will be buggered and the whole experience.... Oh your talking about the front axle! Never mind.
How do you weekend an axle ? As Trump would say drill baby drill ! My front axle is cut in two narrowed and drilled. Put in a 40 ton press and bent for alignment and never failed. I wouldn't worry about drilling a few holes in it.
Well that was embarrassing. Fixed it, thanks.
Maybe the question should be, has anyone experienced a failure with a drilled front axle?
fan of both drilled and non drilled.. but I'll go with non drilled, chromed and the insert painted to match.
Most of the time, when you remove metal, it weakens the item! How much? Depends! Drilling an axle right takes some skill and time and possibly some money. That being said, if I wasn’t sure if I liked it....... I wouldn’t do it!
On the flip side.... if I really liked the look..... I would do it!
Each to his own!
The structural strength of an "I" beam axle, is just that, an "I" beam. when you drill it, especially with holes that are large, you compromise the strength drastically. Yes, I know that people have been doing it for years, but facts are facts. I vote to not drill it, looking cool is one thing, safety is another.
strength aside, personally I like the look of no holes, on most components. I don't mind sheet metal with dimple died holes in a tasteful way, but I'm not sure how HAMB friendly dimple died parts are.
I'd like an engineer to chime in. I believe that a hole being round would not have stress points due to th elack of corners and therefore if not excessive would not be overly weakened. But as I said a structural engineer should comment.
48 yr Mechanical Engineering grad & practicing eng'r. Beam axles are I-beam section members. That shape derives all its strength from the top (in compression) and bottom (in tension) flanges. The web between only has to keep the top and bottom flanges from deforming, adds virtually no bending strength. Thus just about any drilling pattern has no detrimental effect on axle strength. Some guys take that to an extreme and cut long slots removing a lot of web. This does endanger the top and bottom flanges collapsing but if just drilling, not to worry. Just keep the holes in the web and don't remove any flange.
Had these for 28 yrs on my daily driver, zero problems.
The ends on mine, are drilled. I didn't want it all holed up. I like it, like this. 117Harv's work. Best polisher on the HAMB. I only polish knobs. Well ... one anyway.
Top is polished, and drilled. Bottom is finished polished ... Gibbs oiled.
on a 32-34 highboy
chromed & drilled
@willys36 has it... the web is like a lattice on a truss. It keeps the flanges in alignment so they don't deform under compression/tension. We do large structural members with blockouts in the web all the time, or castellated steel beams that follow the same principal.
If you wanted to get all technical about it you could do a load analysis on the section to determine where to put the holes, but holes are well within the realm of design.
I'm guessing the holes were drilled after the polish work. Bob
I drilled my forged axle, I like the look and it will be plenty strong being forged steel to begin with.
The drilled axles I’d be most concerned about would be the cast axles like Magnum for instance.
OK, For the historical record who had the FIRST drilled front axle and when? Photos would be nice to see. Bob
You are not supposed to chrome them either, but....
I'm absolutely not an engineer! haha!
But if a piece of flat bar has holes in it, surely that would make it easier to bend (on edge, the "hard way"), than if it didn't have holes? Or no?
That's essentially the "web" of the I beam, right? Flat bar bends easy on the flat sides, and difficult to bend on edge "the hard way". The top and bottom of an I beam would bend easilly (with downward or upward force) if the web weren't there?
Or is it the case that these I beam axles are stout enough that the holes don't degrade enough to make a difference during normal use?
I'm sure I'm over simplifying it, hah! I would love to take some engineering classes, I usually just throw way thicker metal at things because I don't know how much is actually needed for sufficient strength, haha
If Henry Ford could have saved 50 cents worth of metal on every axle he made, he would have figured out a way to do it.
Again the top and bottom flanges take all the stress. As long as they don't deform, the web is not needed at all for strength purposes. That idea is impossible without the presence of something holding them in place. enter the web on an I-beam, the x-pieces on a truss (steel bridge, wooden roof truss, etc.) If you want to investigate the math, find a text book that describes calculating the strength of various shapes by first determining the moment of inertia. The bigger the area of a shape component, the farther away it is from the center of mass, the stronger the composite shape is. The web of an I-beam is right at the center of mass and has little area so not much bending strength in any direction. The flanges have relatively large areas and are spaced far away from the center of mass so have lots of relative strength. The web's job is to keep them steady via the center of mass. Holes have zero impact on them doing that job.
Envision what each component of an I-beam is doing when trying to bend it. The top flange is being shoved, trying to compress it. The bottom flange is being pulled. Neither has much bending stress so the shape is very strong since steel has very high tensile (pulling/compressing)strength. The web is being slightly bent but is insignificant compared to the push/pull of the flanges.
@flamedabone ... HOLY SHIT !! I love it.
So supposedly, you CAN chrome steel and remove molecular issues from the process, by baking the chromed parts for a time frame, immediately after the chroming process. Like within, hours.
I can't tell you the looks the chrome guys give you, after saying as such. I haven't found anyone yet, as "educated". I'm some sort of whack job to those guys.
Another misunderstood process. Hydrogen embrittlement is real but only happens on high strength steels over 140,000psi yield strength or Rockwell hardness of 32HRC. This is in the range of grade 8 bolts and stronger. Weaker steel alloys do not suffer from this and that includes axles, frames, etc. those can be chromed and welded with no hydrogen embrittlement problems.
I have to agree. That axle is sleek and slick. Nice change up on the hole(s) placement.
Let me throw this out there. Think about those running wire wheels. Thin spokes with lots of air in between. I suspect the outer ring acts just like the top/bottom of an I beam.
Yeah it's got holes in it! They match the shock mounts.
I like mine drilled but hate seeing drilled axles with that big gap in the middle saying Super Bell. There needs to be a hole right dead center.
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All the comparison of a drilled axle to a truss goes out the window the minute you put twist into the equation. A dropped axle twists with braking force due to the lever action of the drop. Trusses don't have twist factored into their load bearing. Holes weaken any I beam axle unless it doesn't twist.
OK, so as this debate continues on, I keep envisioning that Ford axle with all those full circle twists in it. So,how many twists are in it? 20, maybe more, maybe less? I'm sure someone could post up a picture and maybe we can count the number of twists, but lets go with the 20 full circle twists (which is probably a lot less then counting might show), just because we need a number so we can understand.
So we take a fresh Ford axle, and drill holes in it, then we twist it in circles. I can see where the holes are going to weaken the axle as it twists. The question is, how much did we weaken it with the holes? Lets say we lost 50% of the axles strength when we drilled the holes. Would that mean the axle MAY fail after 10 full circle twists? Remember, the original one didn't fail after all 20 twists.
I'm not seeing a life threatening event going on here. I can't imagine an event where the axle will see the twisting force that axle went through in a normal axles life span, which has carried on for many years.
Hot rodders have been drilling holes in axles for many years. It would be interesting to find out exactly how many have failed in all those years. I suspect that number is pretty low.
We tend to do a lot of unsafe things with our hot rods, I believe drilling holes in axles is probably one of the less unsafe thing we do.
That said, if your not sure you will like the look, I can tell you without any doubt, its a lot easier to remove the metal with a drill then it would be to put the metal back in the holes, if you don't like the look. Gene
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