More Welding Jig

I've made a little more progress on the welding jig. Yesterday I concentrated on setting the fixtures, I had to build a couple more to get the height just right between the donor frame and my main boom tubed. I also cut and began to cope tor the first weld joint in the process:

The block- making process is tedious and time consuming, but you can get some good results if you're patient. Working on that...

Not easy to see in this picture, but on the upper tube I've begun the process of curving or "coping" the end of the tube to conform to the down tube of the donor frame.

 Here's a nicer overview shot of that area, and the jid itself. If you look closely at the connection of the main beam and it's vertical support, you can see the shims I added to keep it straight:

These are shots of the finished rubing block fixtures for the bike's main load beam. This design does the trick, but the slots re rather tricky to cut with what I have available. I've already modified this design somewhat to make that easier without sacrificing anything. The new desigh even saves some material too..

That's all for now, More Later.

Using recycled materials

I've recently been spending time at Free Cycles processing some material.
This usually involves cutting up bicycle frames and deconstructing wheels to get the hubs or the rims.
I did a Lot of this in preparation for building some cargo bikes several years ago, so this time I know exactly what kind of parts I need and approximately what quantities to do what I want to do.

The biggest issue when your resources are free for the asking is quite the opposite of what one needs to deal with in purchasing resources. Instead of not having enough, you end up having too much.
Problem is, Since the resources are free or practically so, the stuff is viewed as not having any value, and that means Anything could happen to it unless it's in you're possession somewhere. The resources are Available, but often they are Vulnerable- To being thrown out or otherwise carted away to the landfill by property or business owners who don't want it around, vulnerable to other collectors of such materials, who could show up at any time, vulnerable to the Elements, as most discarded resources generally end up outside.

One must collect up and store any materials they want to use in order to preserve them in a useable state, or keep them from simply disappearing. This takes dedicated space, as most of what one is collecting as a resource is not the sort of thing one wants to live with, Particularly since it generally takes a substantial quantity of individual-consumer discards to constitute enough of a resource to produce something substantial with, and Space Costs Money.

There is a danger in this, of overwhelming the space one can afford to have available.

A person has to have a bit of a scavenger's mindset, It's become counter-intuitive to most people to think in any other terms besides buying new. It's just unheard of anymore, the cultural mindset had turned almost completely to consumption. Even those with the least material resources of all dream of the most conspicuous forms of consumption they can imagine.

This creates kind of a social disconnect as well. Put simply, People think you're crazy for saving up a bunch of old junk. There are Names for such people... Like Hoarder. Names that speak of derangement and total disconnect with reality.
There is a danger of this actually being the case. There is a definite like between someone accumulating a large mass of some resource thought to be useless for some project that they intend to do, and those who do it just because they aare driven to by some other urge.

A person has to firmly have a goal in mind before aggressively collecting anything makes sense, or makes anything more than a mess. A person needs to have a good idea of how much is needed, so one can stop collecting and move on to processing it and then doing the project.

This can require a Lot of patience. A lot of times I'll get an idea for something, but it's fairly complex, and requires a lot of material resource, which just can't be accumulated quickly. I want to just DO it, to begin working immediately on creating the thing I see in my mind right now, before it fades, before I get distracted by other things and Forget. Experience with myself has taught me that trying to build anything before I have all the materials just leads more often than not to a half finished project being abandoned in frustration.

Welding jig evolution

Well, my shop space has changed a couple of times since my last post here, but the project is still the same, and has been making some interesting developments in this long time of silence.

My primary interest is in creating human powered vehicles, and the current project is building my next long john style cargo bike.

This one has served me well for about ten years now, but it's quite long in the tooth and there are things about its construction I was never happy with.  

...Like the fact that the basket is crooked, because I just Did it, by hand and by eye without any kind of fixtures at all. It tracks straight and rides really well, but the sides of the basket were kind of an afterthought. i was so impatient to ride it  by the time I go to that point that I rushed through it instead of taking the time, and the results have irritated me a bit since then.

To be more accurate, the current project is developing a System for creating cargo bikes from the available resource of older bicycles, recycled and repurposed. 

The efforts of the past six months have been intensely focused on creating a welding jig for ensuring straightness and accuracy. 

It’s taken a couple of different forms as I thought about it and tried things out,  I have photos documenting the things I’ve tried, but now I think I’ve finally hit on something that will work, and work well.

I’m almost ready to try it out, I the basic structure is finished, and now I only need to create the specific attachments for cradling the tubing and mating up with various shapes.

 

The first idea I had was... Interesting.

I used a flat base and drew a 1" grid on it, intending to use it as a layout tool.

The idea was pretty basic, Use the grid base to keep everything relatively straight, build fixtures to hold all the tubes,

 These blocks were just place holders, of course. They were the only things I could make with enough precision at the time. I didn't have a drill press or any effective means of clamping, and I really wanted to at least mock everything up to get a better idea of what I needed to do for it next

 

I hadn't worked out anything for securing the blocks to the board, or securing the tubing inside the blocks, I was really just playing around with ideas at this point. I decided to actually do the grid and start thinking seriously about using this design because i came up with somehting I liked while playing with the parts:

I do still plan to use scooter frames for putting together a longjohn front end at some point, but this was just an idea I didn't get a chance to complete. Some of the basics of this idea have carried through, though. I figured out how to cut a BMX fork in such a way that the curved shoulders of the fork legs will form a 90 degree angle:

That's something I've kept working with.



That was about 2012 or thereabouts. As it often does, life got in the way, and the parts of this project got scattered.
The next thing I tried took a different route. Instead of the wooden graph base, I decided to build with steel:

The base was made of metal sawhorses and angle steel from bed frames.

I bolted the whole thing together with 5mm cantilever brake hardware, but only at the very ends of the angle steel rails. Each rail was two pieces of angle steel with a spacer between them to create a channel. The clamps in the picture about were for applying pressure on that channel to lock things into place.

I switched to wood for the blocks, as now I had better tools. I used small cut ends of the angle steel itself to create the tabs on the undersides of the blocks, which then slipped into the channel created by the two long angle steel rails. Then the clamps come into play.

This jig worked fairly well at holding the parts in place, but it wasn't as precise as I was looking for. The tubing pieces were now securely mounted into the blocks, held on by screws, but in drilling and cutting the blocks, I was still working by hand. The mounting holes for the screws didn't line up right, making the caps want to go on crooked, the tabs in the bases would want to move around, and it was difficult to get them positioned precisely in the center of the block, so they'd be just slightly off, but when all the parts were bolted in that "slightly off" would turn into "Way off" where the tubes were supposed to butt together.

Cutting the forks by hand was tricky too. It was very difficult to keep everything straight.
And this design fell out of favor as well.

I still have all the blocks from this stage. I'm thinking about ways to integrate them into the system I have now.

I didn't continue working on this for long enough to get past the initial basket shape for the long john and start thinking about how the rest of the bike would interface into it, I just took it apart. I had a better idea anyway.

A couple of years before, someone had shown me a design for a wooden sawhorse.

 I immediately saw the potential, but at the time was sure the bed frame welding jig was going to give me what I needed, so I just put that design on the back burner. I changed work spaces a couple of times, too, so it was all I could do to keep all the parts of my various projects together.
Time passed, and the idea finally came around again. I decided to try it.

It's double layers of 3/4' plywood, so it's pretty hefty. I have more images of how it went together,
but I won't post those right now. It went together okay, with some slight adjustments needing to be made to get the pieces to fit. i had trouble with the notches, because i wasn't sure how to cut them in order to get straight, clean edges that locked without play...

                                                                      Mind the Gap...

I eventually fixed all that with shims and figured out how to keep it from happening again. I had tried to use power tools to cut the first slots, but just couldn't get enough control to keep things straight and tight, so I eventually switched to a hammer, chisel, and wood file for making the various slots and cleaning them up to be able to function.

The finished structure is completely slotted together, everything comes apart and the major pieces all pack flat.
The fixtures that connect the tubing and the donor frame to the jig won't pack flat, but they don't take up too much space. This time I started with the donor frame instead of the basket area, and worked forward.

The fixtures are designed to cap over the main rail, so they can slide up and down for height adjustments.
The vertical slots on the fixtures correspond with horizontal slots cut into the main rail itself, giving the fixtures back and forward to give length adjustment, for dealing with different sized donor frames.

I used bike axles for the threaded shafts here, but as you can see the wheel nuts are too small to properly deal with the width of the slot, so I'll be putting some big old 1 1/2' washers on either side as well.





The fixtures holding the rest of the tubing, the load area, etc,are oriented a bit differently, and so are harder to clamp.

I plan to secure the tubes into place using really long hose clamps looping around the bottom of the main rail. The fixtures pictured and are not the finished article They have an additional block on either side to keep the fixture perfectly upright. I managed to cut and dress the slots for all of these so there is no slop or play.

 With all the rails being the same width, I can position the fixtures anywhere on the rectangle to support the tubes securely without being too close to the heat, except in one place, where the wood will be protected by copper sheets nailed into place on it:

This is the bottom bracket area, It's critical, because it's where the Cargo portion primarily interfaces with the donor bike, as in my previous long john. 

Not the best looking weld beads in the world there, but they were among my very first, and they've held strongly for nearly a decade now, and seen much hard use.

The photos of this area are kind of dark, and the paired horizontal tubes for the load beam have not been cut or coped yet, so it takes a minute to see the relevant details. Sorry. about that. Lighting is an issue in the shop I'm in now. Hopefully you can see just how the bottom bracket shell is contacted.

So that area is going to be capped in metal, because whether I decide to fillet braze or weld for that particular joint, there's no way the wood of the fixture is going to be more than a half inch away from the arc, or be bathed in flame.

I might end up having to find a different material for that bottom bracket shell cradle anyway, but I'm going to try copper sheets and little tiny nails first, because i think it might work.

I don't have enough fixtures made to fit everything up yet, or even to outline the bed/basket area.

That'll be what I'm doing tomorrow.

This catches the project up to the present. 

The first photos in this post were taken in 2012. Most of this work happened this year. This represents me thinking with my hands and working to figure out what I wanted with the actual parts instead of writing very much down, although by the time i got to the sawhorse stage, I'd pretty much given on Documenting vs. Doing the Thing, and started making proper drawings. 

I've actually got a bunch of drawings of my ideas for bike design, but I kept viewing the jig itself as simply a means to an end, to be handled quickly and not dwelt upon, so the real work of building the bike could begin. Once I got over that and started treating the jig as equally important, it was a lot less frustrating to be doing carpentry instead of metalworking.

Soon I'm going to have to publish that stack of drawings.

Anyway, we're caught up to the present. Thanks for hanging in through the whole process here, and I hope you found this interesting, and that perhaps some of this is useful to you. Feel free to ask questions.

More as this project progresses...