Lightening Holes: just cool or functional

I've always considered it a style thing, and the tubes are for drainage. You don't need water collecting in the boxed frame or in your wishbones.

 

This post is very technical and I don't or raqther Can't add to that, I just thought I would show the process Jeem is refering to.

As a side, this process does bring back the integrity of the boxing plates

 

I agree..its like putting beads in a flat panel..................and if its the look your going for.................Littleman

 

wow, i little part of me feels proud. I have contributed a worthy thread other than new pics of my car. HAHA. Littleman, your cars are unreal and one day I'd hope to have enough money to own one.

 

Couldn't you just use lighter tubing? I would think it would be strong enough, since it's not very long and it's mostly trying to resist compression or stretching, and also some twisting . Look at how those thin driveshafts hold up...not exactly the same but....

 

I think even with the lightest tubing there is still a gain or the loss is neglible.

 

Dude, you think too much.

 

maybe i do, maybe i do. But the only way I'm going to wrap my head around this whole frame fab thing is if i ask questions like this. I'm a youngin compared to most of you old codgers and I need to ask the questions so one day I'll have the answers.

 

Littleman,

Please - don't take that the wrong way. I am not saying it doesn't work.

Plainly put - It does.

I am just saying that it's not any better than boxed rails w/gussets. It's not any worse either - just different...


And if you think it looks more attractive - that makes it all the better.

If you go to the track and inspect the REALLY fast cars - the top fuelers for instance - and put your fram next to theirs... yours will look like a Sherman Tank.

The only point I wanted to make was that there is a reason for "lightening" holes - and it really is a misnomer because they did very little to actually lighten a car. In fact that affect is minimal unless you are considering reciprocating/rotating masses...in which case they are very helpful.

That and they stopped cracks from totally breaking your car/part all the way through....


..which could save your neck...



......what I mean to say is that Littleman - your car is sweet, and I imagine it will do what you want it to.

There's more than one way to skin a cat.


The point of this post was to answer the question about lightnening holes - not to pick apart someones hot rod.

That's all.

 

neat stuff, but I was never good in math... here is an answer from one of my college quizes...

 

Trust me Broman..no harm done...I do not look at it that way.....at all.....the holes I blasted through are obviously not for weight loss, hopefully the torque from the Hemi will make up for all the weight gained..........I just wanted to show that their are reasons you would want to sleeve them.........I love the look of the real early coupe bodied salt cars........I have drilled a car full of holes back in high school for less weight, I have drilled and sleeved and have drilled and belled them, it all depends on that holes function, personally if I were to drill a car for less weight, I would bell them all for some strength, depending on the thickness your attacking..........and if I am drilling for weight , I better be running tuned headers and such, because I would be looking for ever advantage at that point, thats for a full on drag car of course, but that can carry over to any street car...........bottom line what is the cars function and how does the builder want to get there.............................Littleman..........drilling a car full of holes for weight gain, is getting into the nitty gritty of going just that much faster...

 

X = 5cm, that's easy a 3, 4, 5 triangle is a right triangle. This is some funny shit to read, beings I am a Civil Engineer.

 

that was an easy one for sure, especially since we are talking about cylinders instead of triangles.

 

thats a good point.
1.If you are going to drill holes in your frame its more of an aesthetic descision as the weight you might shave off would be negligible in the grand scheme of things
2. If you are going to do that you probably would want to use pipe because you would get all kinds of leaves and dirt and water collecting in there.

 

Thirtyfivepickup - I got your joke....

Some of the others should lighten up a bit. (pun intended).

Littleman - I'd fill the holes too if I was building a Hemi.

BTW,

I wasn't making this shit up. I read about it in old fabrication mags once. I also wondered why folks would drill holes all over the place, so I looked it up the hard way - yea you know - in a book. 'Course I did manage to graduate high school and go two years through college before even seeing the internet.....Yea, once upon a time people read books, it was crazy! We din't have air conditioning or cable TV either, and noone died because of it. I keep trying to convince my wife about things of this nature, but she can't seem to grasp the concept of life without luxuries like cell phones and e-mail and reading the news blogs on lunch hour.....ohh well......:shrug:

 

I drilled about a dozen 2 1/4" holes on each rail of my HA/GR. I filled these with light tubing. This really did the job to stiffen the frame. Before, if my son stood on the frame, you could see it flex (150 lbs max). I'm pushin' 260. Now I can stand on top with no visible flex. It's also more stable on the track. That's all the proof I need. I'll use filled holes on my model A. I ain't posin.

 

I ran this past my wife who is a math wiz and she just sat there and thought about it for a minute. Then she stood up and said that if she ate a dozen donut holes, she would definately gain more than a pound and blame me for letting her do it. She then smiled and walked out of the room.

Now I'm really confused and have an unexplainable craving for Tim Horton's. Thanks.

Vance

 

Just for fun, I did a little something to show some stresses in a 48 inch long piece of standard steel 4"x4"x3/16" wall rectangular tubing.

Here's what it looks like with welded ends and 2.5" diameter holes with no tubes welded in


Here's the same piece with 2.5" I.D.x.0625 wall tubing welded in


Okay, big deal, pretty pictures... here's what I did with them

-2000 pound distributed load across the top supported on either end. This picture shows what it would look like with over exagerated deformation, but it shows the stress levels at each hole and what the material "wants" to do under load. These are shown with a factor of safety of 6! Still no red on either of them and the numbers show that they are both really close in terms of stress.

Holes only:


now with the ports AND tubing welded in


Sorry the numbers can't be seen on the side. Didn't want the pictures to take up too much room.

But wait! There's more! I have point loads to show which will be more applicable to what we do around here.... hold tight!

 

Now for the point loads.

Same beams but with 1000 pound load concentrated on the center of the beams with a 2x2 foot print (about the size of an engine mount). These were done with a safety factor of 3.

Ports only, no tubing


ported and filled with the same tubing


Same deal. Exagerated deformation to show what the metal WANTS to do. Nothing is in the red on either of these.

So what the hell am I talking about?? What's my point??

Both beams are strong as hell even with 2.5" diameter ports. The tubing seemed to add a little strength of course, but not alot because it was only 1/16" wall tubing (basically exhaust tubing). It appears from the quick study that all the tubing would do is keep crap from falling/collecting in the frame.

 

Great info! While you're at it, test tubing with NO holes, and test all three for twisting (torsional?)force resistance.
P.S. How about 2x3x1/8", seems to be the most popular (and what I'm using!)

 

Just one more bit, these beams were shown not attached to anything. Obviously we're not going to have something that long and not welded to something else like a K-member or some type of other lateral support. We also run everything in parallel (ish) when building a frame so all this would be essentually decreased. Even though this demonstrates how things would look sitting in the shop and not on the road, based on what I see here, even in the dynamic state (driving and bumping down the road) these are still really strong.

 

Give me a bit. I need to do some work around here. I'll show some hypothetical torsional stuff. Doing a solid 2x4 beam would be MUCH stronger and have a great deal less stress. The diagram I would do whouldn't tell you a whole lot. It would basically look the same, but without the holes and without the greenish colors mixed in.

The 2x3x1/8" won't be too much less as long as you scale the holes down appropriately. I would suggest using thicker walled rect. tubing (3/16") if you're going to port it though.

 

All that math wasted on something that is done because it looks cool..............


Or in Littlemans case (as well as mine) to beef up some pie cuts

 

ok, my mind just exploded.

 

Okay, here's the torsional stuff. We would see torsions very different in our frames becuase of the way things are supported. The entire frame would work together sort of like a web. Each member would provide suport in some way. However, since we're just sort of doing this for "fun" or whatever you want to call it, here's what they look like.

Reduced to a 200 pound load at the end of a 6" lever and restrained at just one end. Factor of safety shown at 3 however it showed nothing worse than 4 and some change...

Without welded tubing


And here's with the welded tubing inserted


As you can see, there is a little red in there this time. We would never load any members of our frame like this. This is only held at one end and completely disconnected from everything. But, it shows where the stresses would be located when put in torsion. The diagrams aren't totally worthless.

 

I've already started it with 1/8" wall.

 

What's wrong with a hot rod looking cool? Isn't that a BIG part of it?

 

coolness and WOW factor are a huge part of building a rod, I was just wondering if the lightening holes had something to do with speed or style and the response generated from this thread are overwhelming. I couldn't have dreamed I'd get such well thought out and concise responses like from Littleman and Scooter.

 

There's some sharp motherfuckers here, those are just two examples.

 

Dipshit, look at any pics of my touring. I HAVE DRILLED AND FILLED framerails! Yes, I did it because I liked how it looked. Without style we would all be driving Yugos.

Scooter, thanks for those tests. Fun stuff to look at.