Bolting VS Welding.

[J_Walker]

Well, I found someone locally to me again to help me with welding. [mostly just someone who owns a machine!] he's got TIG and MIG machines, mostly keeps them in the bed of his truck [covered of course] so that makes it easy for me when I need his help.

I was talking about building a pedal powered "gokart" since I bike a lot, one would be pretty neat to make, and cheap!

well one thing lead to another.. and we got to talking.

"A pipe would break before a good weld would"

then he showed me this book, I don't know the name of the book, but it was really cool. comparing using bolts VS welding.. and I thought to myself, wow this whole time we're telling someone who wants to build a simple 20mph gokart that they must acquire a welding machine first to weld some steel. to have a safe gokart, but is it true? well according to said book, that's not exactly true. Two 3/8th bolts will hold a joint together as well as a weld would.

There was a few pictures in the book that showed ways to use bolts in tubing. my favorite was a "bushing" kind of piece of tubing that acted as a spacer inside the piping, so when you torqued the bolts down, they wouldn't squish the tubing.

Does it look as good as a nice roll of dimes? No, it doesn't. but would it function as good, and be as safe? sure will!

Now, for anyone reading this, I'm not saying to go out and build a gokart with a 250cc engine out of dumpster wood and some bolts. No, you still have to using tubing. and your brain. But I believe that this should be at least looked into, at best.

 

[itsid]

Oh, just think about checking all the bolts every other time just to make sure they didn't came loose on your last ride..

'sid

 

[J_Walker]

Oh, just think about checking all the bolts every other time just to make sure they didn't came loose on your last ride..

'sid

Red loctite! You need a torch to get that stuff off! but indeed that would also be a PITA. like I said, its not an fix all alternative to welding. as welding does outweigh the rights of just using bolts. It's just a thought, I considered it on my pedal kart. not exactly keen on rattling loose bolts either!

but don't forget, they make those neat little washers, where they are like normal washers in a sense, but they are cut, and lifted to create a springy effect, I've used those before with really good results, without loctite. I forget the name of them..

edit: Helical Spring Washers

something like this image would work I think, just make sure the bolts are "falling with gravity" So if you lose a nut, the whole thing wouldn't come falling apart exactly right away. Again, until I actually build something that allows me to use this bolt method. I'm skeptical.

also another alternative. is to use something like maybe cotter pins? Torque your nut down, mark the place it sits. take a tiny drill bit, and a drill a hole. buy a box of cotter pins, install them. Works wonderfully on keeping my motorcycle's rear tire nut from rolling off

Over all vibrations would also be a consideration. Gokarts already have it bad enough welded, what would that "free play" in the frames feel like?! only way I would think to counter act that, is use some sort of rubbery hard plastic to dampen the vibrations..?

 

[itsid]

cotter pins are great,
but spring or even sawtooth washer are not (IMHO)
I'd rather rely on nyloc nuts than these washers...

Anyway, I like the idea of bolts (especially the 'easy undo if necessary' part )
but for vehicles I think I'd rather go for welds (being chicken and all )

I'd love to see what you can come up with.
So make sure to post a build log of the pedal kart

'sid

PS Oh, and if you can, please find out the books name and author; I think this might be interesting.

 

[OzFab]

Yes, bolts can be as strong or stronger than a weld but, how would you join two pieces of tube at 90° to each other with absolutely no welding?

 

[itsid]

Yes, bolts can be as strong or stronger than a weld but, how would you join two pieces of tube at 90° to each other with absolutely no welding?

..with a small third piece in the corner, or a trapped nut, or barrel nuts, threaded rod inside one of the tubes...

'sid

 

[Doc Sprocket]

While possible, I'd call it far from practical. For the amount of effort required to properly build an entirely bolted-together frame, the poor, wretched, welderless masses would be far better off to scrape together $100 for a low-buck buzz box.

 

[OzFab]

 

[jjarkys]

now, for anyone reading this, i'm not saying to go out and build a gokart with a 250cc engine out of dumpster wood and some bolts.

lol.

while possible, i'd call it far from practical. For the amount of effort required to properly build an entirely bolted-together frame, the poor, wretched, welderless masses would be far better off to scrape together $100 for a low-buck buzz box.

x2

 

[itsid]

Me too..

but if I got John correctly, that's not the point,
the point was, is it reasonable that we tell 'everyone' that it cannot be done?

And I think it's nice to know, that under certain circumstances it's not a bad idea at all;
and in fact it could be done.
(That's why I asked for the book, to maybe lighten things up a little more )

'sid

 

[Doc Sprocket]

Speaking personally, I tell people not to to a bolt-together frame because in my own humble opinion, it's a daunting enough challenge to engineer one's own frame- especially as a newbie, and doubly difficult to properly engineer a bolt-together affair that's not going to fold like a cheap suit.

Now- "Newbie?" you say? (I heard somebody out there question that.) Yes. Why? Because the odds are VERY good that someone competent enough in fabrication to pull this off, is likely to have access to a welder.

It is for very similar reasons that I advise people to avoid wood. Sure enough, it can indeed be done- and quite stoutly, too. But the very last thing I want here, is to see some kid die in a flaming pile of toothpicks.

Therefore, when faced with either of the above, I tell them they are best to source a good, used frame somewhere, and build up from there.

 

[jjarkys]

Now- "Newbie?" you say? (I heard somebody out there question that.) Yes. Why? Because the odds are VERY good that someone competent enough in fabrication to pull this off, is likely to have access to a welder.

Or they just have to much $$ and time on their hands and want to be unconventional. Like this guy.

http://youtu.be/keAkjqjnFt0

 

[J_Walker]

I'll indeed ask about that book when I see the guy again!

now while I'm still in the planning stages for the pedal car thing. I'm having a problem on frame setup. for the lightest weight, but the most strength per the weight. Blech!

Also the splitter car, I saw that a few weeks ago for the first time on youtube too.. Lol

wood veneer and epoxy is pretty amazing stuff.

 

[machinist@large]

More info needed.....

OK: I guess this is where I'm probably putting my head on the chopping block....

While a gokart built using strictly bolted steel connections is feasible, it's going to be a pain in the to make it work with the same structural integrity as one of properly welded construction. I think one of the biggest obstacles for us to even discuss it logically, is we need to have the title, chapter and verse (as well as the ISBN #) of the reference book John's referring to...

Now, as to building a kart using just bolted connections? you're going to have to go back in history, to a time when you couldn't weld large structures together.... back when the newest and finest things were assembled with....rivets.....

For practical purposes, you're going to need to bone up on the way joint assemblies were designed and built around the turn of the last century (1901; NOT 2001). Bolted construction and riveted both had to analyze the forces involved the same way. And before someone tries to bust my chops about bolts being used in modern construction on a regular basis, let me remind you that the modern uses for bolted construction almost always use welding to fabricate the components to be bolted together. It's an integrated design process that uses the strengths of both types of connection....

I guess I would describe it this way; if you're looking for maximum strength from the least amount of weight, go buy a welder. If you are looking for options in design, start studying. I won't claim it can't be done, just that it's not as simple as you would think at only a glance....

 

[Scout]

Now, as to building a kart using just bolted connections? you're going to have to go back in history, to a time when you couldn't weld large structures together.... back when the newest and finest things were assembled with....rivets.....

For practical purposes, you're going to need to bone up on the way joint assemblies were designed and built around the turn of the last century (1901; NOT 2001). Bolted construction and riveted both had to analyze the forces involved the same way. And before someone tries to bust my chops about bolts being used in modern construction on a regular basis...

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.

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.

 

[itsid]

..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 vehicle 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

 

[J_Walker]

OK: I guess this is where I'm probably putting my head on the chopping block....

While a gokart built using strictly bolted steel connections is feasible, it's going to be a pain in the to make it work with the same structural integrity as one of properly welded construction. I think one of the biggest obstacles for us to even discuss it logically, is we need to have the title, chapter and verse (as well as the ISBN #) of the reference book John's referring to...

Now, as to building a kart using just bolted connections? you're going to have to go back in history, to a time when you couldn't weld large structures together.... back when the newest and finest things were assembled with....rivets.....

For practical purposes, you're going to need to bone up on the way joint assemblies were designed and built around the turn of the last century (1901; NOT 2001). Bolted construction and riveted both had to analyze the forces involved the same way. And before someone tries to bust my chops about bolts being used in modern construction on a regular basis, let me remind you that the modern uses for bolted construction almost always use welding to fabricate the components to be bolted together. It's an integrated design process that uses the strengths of both types of connection....

I guess I would describe it this way; if you're looking for maximum strength from the least amount of weight, go buy a welder. If you are looking for options in design, start studying. I won't claim it can't be done, just that it's not as simple as you would think at only a glance....

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..

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...

 

[itsid]

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*

 

[Poboy kartman]

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.

 

[Scout]

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

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.