Bolting VS Welding.

[machinist@large]

Semi trailers have their sides fastened with rivets… Keep in mind that those rivets, as well as the rivets used in olden days, are not the pop rivets you buy at the hardware store. They are solid rivets hammered/peened in place, either with heat or by sheer force.

The reason the side panel's in your example are riveted instead of welded together is because of the grade of aluminum they're made out of; they fall into a class of types that are heat treated, and can not be reliably welded together. That includes spot welding, which would be the most preferred way to assemble such a structure if it were made of steel.

Were I to build a bolt together kart, I would most definitely use sleeves (The "spacer" that goes in the tubing) and either loctite or locknuts, preferably the non-nylock ones.

Non nyloc? is there a reason for this (I use them alot) well not U.S or AUS TM ones of course but nylon inserted nuts
Do you think there's something wrong about using them?
Not a single one came loose (well mainly because I never build a vahicle with them of course) but I also used them on my cars over the years.

Now I'm baffled, please let me know, maybe I have to rethink my behaviour (i.e. at least check them again... now it's set and forget)

'sid

Used correctly, the nylon insert type work well; I'm guessing the reason you haven't had any issues, 'Sid, is because you haven't exceeded their intended operating range.... And with all the types of thread locking compounds available out there now a days, most people should be able to find something that will work in their application....

Having to delved into 1800's rail road construction some time back ago. the problem wasn't the riveting of the rail road bridges, it was the metal used to do it.. Iron alone could not hold the stresses steel could. Once steel became available, they used it to build some well known bridges today, that are still standing and still working like they where "almost" brand new. and even then, the steel was riveted. I think now, most were updated though, and welded at major stress joints..

Why do people seem to think that I'm saying riveted and/ or bolted construction is automatically bad or wrong? If you go back and re read my post, nowhere did I say it was wrong, or couldn't be done. All I said is that it would require more thought and planning than many people seem to think it needs.

By all means, weld if you can! I'm not saying to go free willy and bolt your stuff together, without an ounce of research into the subject.

For someone like myself, I have been making friends who will on occasion let me use their welders, and I've personally come to enjoy stick welding [TIG] It just has so much control, and I feel like I screw up less with it, because I had done a lot of soldering during my childhood.. now I'm sure I'm gonna get even more heat for comparing TIG to soldering...

John, you're confusing the two processes again; stick welding, your filler rod is also the electrode that carries the current used. Tig welding, the electrode is held in a separate torch body, and only serves as the delivery system for the arc, and the filler metal is supplied separately. As for your description comparing Tig welding and soldering, Tig can only join similar types of metal; soldeing can be used to join many different types of metal, due to the low melting point of the metal being used to "glue" the join together.

Well AFAIK, welding is still not allowed for most (if not all) structural parts of an airplane.
Those have to be riveted!
friction-stir welding is the only exception and that only has been done to floor panels of an airbus A400 military transport yet.

'sid *slowly strolling away whistling*

Traditional aluminum alloys used in aircraft construction are usually considered to be unweldable, hence the riveted construction. Friction stir welding is the new exception; so new in fact that it's being developed as we speak, with your Airbus application one of the first to make it out of the lab and into the real world....

I built a lumber rack for my little Toyota pick-up without a welder years ago. I used two 12 guage triangles about 6" long to make the 90° uprights and attached them with self tapping sheet metal screws. Those started working loose so I used a two part epoxy on the triangles and the screws and they haven't moved since. The whole thing is one inch square tubing bolted together with 5/16" nuts and bolts with the aforementioned lock washers. Contrary to popular belief, those washers don't hold by spring action but by the sharp edges of the cut ends digging into the metal. Anyway, despite putting 100, 000 miles on the truck and many many hauls so heavy I had to be extremely careful turning without putting the truck on it's side- nothing has failed. Not a single nut has come loose. I didn't use spacers in the tubing or Loctite. By now rust may be on my side.lol. You guys up north could just drive a bolt together kart on winter roads- Loctite red? - meet your one-uppense- Loctite brown! Lol.

The nylons are supposed to be a one time use only nut. They work mainly by friction, whereas the other kind is an interference fit type.

Back in the 40's a lot of warships were built with rivets. Electric welding technology came about, production was streamlined, and ships were built in a matter of weeks rather than months. However, every single ship that was welded together sank, while a few of the riveted ones survived. It's theorized that the issue was the welded sections would not allow the ship to flex slightly as it passed through waves like the riveted ones did. Add to that my theory that metallurgy back then wasn't what it is today, and semi-skilled welders not laying a good bead added up to disaster.

Metallurgy has improved tremendously since WWII, that is true. What isn't true is that many of the ships built with welded joints sank because of that fact; what got most of them sunk was the fact that they were prime targets for the enemy, transports and cargo ships. And while there were design flaws in the hull plan for the first class of liberty ships, the design was quickly modified to remedy the problem. At the same time, the US Navy was leading the charge to help codify and develop the use of the arc welding process as applied to naval ships. That included training the yards on how to weld.

 

[Poboy kartman]

It's 34° f and raining right now but I will post up a picture when the weather permits taking one.

 

[J_Walker]

I kind of meant both, machinist. I'm not the best speeler, or use of gramma. one, you tap to get started. while the other you heat the area, then apply. Like soldering...

again, refer to my INB4 statement about "SOMEONE" gonna correct me on my comparison... It was a quick an easy statement, wasn't much thought put into it. Sorry again, but do you always have to get so frustrated with EVERYTHING I say?

 

[Poboy kartman]

I kind of meant both, machinist. I'm not the best speeler, or use of gramma. one, you tap to get started. while the other you heat the area, then apply. Like soldering...

again, refer to my INB4 statement about "SOMEONE" gonna correct me on my comparison... It was a quick an easy statement, wasn't much thought put into it. Sorry again, but do you always have to get so frustrated with EVERYTHING I say?

He's not frustrated, he's just clarifying what you were saying.

I wasn't sure what you meant either. So "stick" with "soldering" cause you can't weld a "Mig"- not even with a "tig"- wait, what the heck did I just say?

 

[machinist@large]

Grrrrrrrrr.....

I kind of meant both, machinist. I'm not the best speeler, or use of gramma. one, you tap to get started. while the other you heat the area, then apply. Like soldering...

again, refer to my INB4 statement about "SOMEONE" gonna correct me on my comparison... It was a quick an easy statement, wasn't much thought put into it. Sorry again, but do you always have to get so frustrated with EVERYTHING I say?

John, the thing that had me seriously annoyed was the fact that NO ONE seemed to understand what I meant about proper joint design; i.e. looking at the way riveted structures are put together as a reference point for starting a design on a bolted structure. Bridge, gokart, ship, whatever. Just because you calculate that a pair of 3/8" bolts would be more than enough to carry the intended load won't do you a bit of good if the rest of the joint isn't capable of handling the concentration of ALL the potential loadings at that one (or two) point(s). Your bolt will be sitting there with a grin on it's face while the rest of the joint rips itself to shreds around it.

That's why I suggested looking at how the old timers designed things to be built using rivets; they had the technology to have used just one big rivet if they wanted to, so why didn't they? Because the stress loads surrounding one big rivet are the same as one big bolt. Anywhere you have a bolt/ rivet/ screw type joint, you have the same issues with how you're going to spread out the load so that not any one bolt/ rivet/ screw becomes the focal point for the load. When the forces in question become to great for either the bolt or the surrounding material to deal with, that is where the joint will begin to fail.

And while welding has it's own share of design issues, it has one great advantage; designed and welded properly, all of the loading on a joint should be carried by all of the joint, instead of just a handful of stressed out areas....

I stand by my closing paragraph in my first statement; "...if you are looking for maximum strength with the least amount of weight, go buy a welder; if you're looking for options in design, start studying......

 

[Poboy kartman]

John, the thing that had me seriously annoyed was the fact that NO ONE seemed to understand what I meant about proper joint design; i.e. looking at the way riveted structures are put together as a reference point for starting a design on a bolted structure. Bridge, gokart, ship, whatever. Just because you calculate that a pair of 3/8" bolts would be more than enough to carry the intended load won't do you a bit of good if the rest of the joint isn't capable of handling the concentration of ALL the potential loadings at that one (or two) point(s). Your bolt will be sitting there with a grin on it's face while the rest of the joint rips itself to shreds around it.

That's why I suggested looking at how the old timers designed things to be built using rivets; they had the technology to have used just one big rivet if they wanted to, so why didn't they? Because the stress loads surrounding one big rivet are the same as one big bolt. Anywhere you have a bolt/ rivet/ screw type joint, you have the same issues with how you're going to spread out the load so that not any one bolt/ rivet/ screw becomes the focal point for the load. When the forces in question become to great for either the bolt or the surrounding material to deal with, that is where the joint will begin to fail.

And while welding has it's own share of design issues, it has one great advantage; designed and welded properly, all of the loading on a joint should be carried by all of the joint, instead of just a handful of stressed out areas....

I stand by my closing paragraph in my first statement; "...if you are looking for maximum strength with the least amount of weight, go buy a welder; if you're looking for options in design, start studying......

I read the frustration in your post, but never forget that the people posting are often 180° away from the ones that don't, and almost always the non-posters outnumber those that do by a large margin. No confusion here on what you posted and I'm far from alone. ... (You know it's true. ...)

Now. ...... Gonna try and post pictures of the rack:

 

[J_Walker]

Alright while everyone's already looking at this thread, instead of creating a new one [if I don't get many hits then I might just end up doing that.]

I'm scratching the pedal kart. Its a good idea, but pedaling everywhere on it will get old quickly. so on a new idea. CycleKart! Only issue I'm having is finding an alternative to the wheels/hubs. TO have them made, is pricey. to buy vintage ones? Even more pricey. So any ideas for Tires/Rims/Hubs ?? I have pretty much everything sourced, even the engine [evil laugh]

 

[itsid]

Alright while everyone's already looking at this thread, instead of creating a new one [if I don't get many hits then I might just end up doing that.]

I'm scratching the pedal kart. Its a good idea, but pedaling everywhere on it will get old quickly. so on a new idea. CycleKart! Only issue I'm having is finding an alternative to the wheels/hubs. TO have them made, is pricey. to buy vintage ones? Even more pricey. So any ideas for Tires/Rims/Hubs ?? I have pretty much everything sourced, even the engine [evil laugh]

No need for "vintage" ones.. you can use bicycle instead of motorcycle hubs, they're also made with internal drumbrakes.
shipping will be the biggest issue if you don't get them locally; but they're quite common in the Netherlands

Why brake hubs? because at least the Sturmey Archer and the Sachs ones I had, can be disassembled far enough to remove the axle and fit a new one or a simple bolt to mount them onto a wheelchair; which is the second best source (but wheelchair wheels are utterly expensive -well around here that is-)

And if you want wider tires than usual, at least some small motorbike rims (36 spoke) will fit a Sturmey Archer bicycle hub (with the correct sized spokes of course, which would be 2.3mm)
Had that done to one of my german muscle krates. a looong time ago

Those Hubs are smaller than the ones on that bugatti, but they're not too expensive.

If you want to have big ones like that, you might want to check ebay;
they're fairly common on a small former eastern german motorcycle.
search ebay.de for "MZ Vorderrad" and you'll find a number;
a little bit smaller than that (wheels hubs and all) but still bigger than a Bike hub are the ones of a company called "Simson" they're sometimes cheaper than the MZ ones too
(A Simson 16" rim is actually what I put onto my 20" bike with a strurmey Archer 3speed drumbrake hub )

If you find hubs you want and the seller wont send overseas, let me know;
I will try to take care of that.

'sid

 

[J_Walker]

well, I'll have to look around the locally before I go looking over seas.. but I'm reading the reason for just not "any" dirtbike rim is a few things, one is rolling the tires over the edge of the rim! second is, motorcycle axles are supported on BOTH sides of the axle, not just one. so it has a smaller axle dia.. on a one sided axle, you need something stronger. there for I'll be looking for something like Honda CT90 wheels [recommended through cyclekart forums] but at like 40-60 bucks a pop. I could go to Walmart and get some cheap alloy tires [not spokes though] for like 100 bucks.. and the 40-60 dollars doesn't include the shipping from all over the US!

of course, I'm not looking for a direct replica either. Just something I can have fun in. so I'm open to alternatives.

also the engine is over 20 HP... so I need a pretty beefy axle.

 

[itsid]

there for I'll be looking for something like Honda CT90 wheels [recommended through cyclekart forums]

Fair idea;
BUT the CT90 Wheels run on 6301 bearings, the same as a Honda DAX or Monkey; with anOD of 37mm and an ID of 12mm (so a 12mm axle)

The Sturmey Archer hub has a bearing retainer for 37mm bearings AFAIR, so you can still mount the same 12mm axle!
But to be fair, those are getting expensive.. more expensive than a new ct90 hub even

The MZ and simson run a 15mm axle

just sayin'

'sid

 

[J_Walker]

Hmm, more and more thought I put into this, the more and more. its not gonna work out. will I ever get to use this engine?!