A few of my favourite photos

For me, these summarise my weekend.....

A massive thank-you for the skills, enthusiasm, support and fun, to Hugh, Jo and TVOR - i am now indebted to you and obliged to finish the project :-)

Hugh, Tim, Jo (photo by TVOR)

She Rolls!

Can you imagine how exciting it is to see your idea come to life as a real rolling chassis?
This engine, rear axel and front forks have all been bolted to my kitchen worktop jig for more than 5 years! gathering dust in my garage and buried under other projects.  And it was quite a strange feeling when we all finally agreed that she was tacked/welded together enough to release her from the jig.

With the aid of Jo's overhead lifting gear, she rose like a phoenix as one solid and complete vehicle.  It was a momentous occasion.  And then, there she was.... on her own 3 wheels.  And I could push her back and forth.
We all took turns to sit on the seat (balanced on a plank of wood) to make "vroom vroom" noises

Note - those pipes sticking out the back of the frame - they're all going to be chopped right back - I want that diff very exposed!

It was getting late in the day, and we had lots of tidying up to do yet, so there wasn't much time for self congratulations, and I quickly stripped everything off the frame so that Jo could (at his leisure over the next week or so) weld up the bits that we couldn't get to while the engine was in place.

For interest sake, the frame weighs 36 kilos (it will change a bit as i cut the tube ends off and add pedal brakets etc

We set about tidying jo's workshop up.  I was going to throw the kitchen top jig away, but Hugh suggested keeping it...... just in case he fancied making a trike too!  And who wouldn't? it is a beautiful looking thing :-)

Saw, Bend, Grind, Weld

The whole process was much slower than I had expected.  
After we had worked out and perfected our bending and fishmouth techniques, I was hoping it was going to be a simple case of "just do it!"   But it turned out that every step of the way was just as tricky as the step before.  We seemed to keep kidding ourselves that "once we've done this bit, it'll be easy!"
Nothing was 'easy', but we did have an increasing skill to sort out each problem, and I did find it increasingly more exciting to see the whole thing starting to take shape (albeit slowly)

This whole weekend was supposed to be as much a pleasure as it was to build a trike frame - and it was - but I was always slightly pressured by the ever decreasing time we had available.  I certainly didn't want to be leaving Jo on sunday evening with a half-finished frame on his bench that he couldn't move out of his way ready for work on monday morning.  And so I did feel a slight growing tension on sunday to get this thing as a rolling chassis - and yet at the same time I wanted to enjoy the chatting and cups of tea and general flopping around that you do when you are relaxed.
Jo seemed relaxed about it all, and so I tried to also.

"Good Enough"

We had previously agreed that our manta for the weekend was "Its Good Enough"
We all suffer from procrastination and wanting to do our best, and this is why our projects have been taking so long to progress.  But with some friendly nudging and jibing, we seemed to make progress simply by reminding each other now and then, "Its good enough" and "Just do it"

Fish Mouths

One of the things that i had been steeling myself for (over the past 6 years!) was the tremendous effort I was going to have to make in creating the tube joints and interfaces.  With limited facilities at home I was preparing myself for cutting and filing each tube joint by hand.  Actually, I find great pleasure in using hand tools, and I'm not bad at it either.... but man, its a slow job.
Added to this the fact that I was planning to weld this frame with my TIG welder which requires much finer fitting tolerances, I imagined that shaping the frame was going to be a log slog.

However, now down in Jo's forge with space, tools, and skills on tap, I was able to re-evaluate this whole process.
Firstly, I decided to ask Jo to do the welding for me.  He uses MIG welding (and he is good at it) - some custom bike builders scorn MIG welding as not being strong or neat enough for bike frames, but as my tubes are larger than most and my design is heavier than usual, we decided that a well executed MIG weld would be perfectly acceptable for my frame - and with Jo doing it, he would be fast, accurate and get a proper penetration.
Secondly, As MIG welding can be a little more forgiving on the fitting tolerances of the tubes (particularly heavy ones like mine) I didn't need to be so fussy about the shaping of the tube interfaces - the fishmouths.

    

There are many ways to design and make a fishmouth in a tube - including hand filing/fitting, drilling with a hole cutter, and using software to print out a cutting template.  Jo introduced me to a very simple method of 2 single straight cuts on a table saw.  There is a great explanation of this process (and much more tube fabrication information besides) on this site.  With a table saw and a hand grinder we were able to create perfectly acceptable fishmouths quickly and easily

Another important decision we made was to not try and make 2 bends in a single piece of tube - so that we wouldn't be faced with having to write off a perfectly accurate bend because we'd cocked up the second or third.  Instead we simple butt welded the single bend sections together (with the use of a tight fitting box-section stub for alignment).  This made it so much easier in the design/assembly/tacking process as we were able to rotate the bends relative to each other to create the perfect shape - and consequently reproduce the exact mirror assembly for the other side of the bike.  With Jo's expert welding on my thick tubes, we all agreed there would be no worries about the strength and integrity of the frame

Subsequent bends

After a little bit of research, it was apparent that packing sand tightly into a tube would support the tube walls during bending.  Some people use heat in the process, and some people warn against using heat.
We decided to do ours cold.
We welded an architectural steel ball into the end of the tube, inverted the tube and filled it with silver sand.  The trick in doing this is to pack the sand down as tightly as possible (we rammed, hammered and tamped with vigour).  Once completely full, we hammered another architectural ball into the open end and welded it in place.
Now our tube was ready to bend.

             

The process worked like a dream!  With a hydraulic pipe bender like this, you dont need heat.  And although I am sure that flushing the sand through with water would certainly pack the sand tighter, we found that we could hammer the sand down perfectly tight enough to give us minimal flattening during bending. 

First bend

3 men for 3 days equals a lot of manpower, thinking capacity, labour and enthusiasm (even more so when you add a good contribution from TVOR who popped in on a couple of days for moral support and sensible suggestions)
With the component parts all lined up and fixed in place we set about doing a first bend on the chassis main rail.  Jo's hydraulic bender made my own 16 tonne bender look like a childs toy.  We made a quick adapter to enable us to use my filed out die to fit his press..... and we gave it a go.

Disaster.  Even with Jo's superior mandrels, the device wasn't man enough to hold the tube taught enough to avoid flattening the tube on the bend :-(  It was getting late in the day (of our first day) and this kink in the tube, kinked our enthusiasm until Jo teased us with an idea;
"I've heard of a technique for bending tube using sand.  I've never done it myself, but I've heard about it.  I've got some sand - we could try it!"
And with that we agreed to call it a day and return tomorrow with excitement to try an experiment.

That night in bed, on my iphone, I looked for some evidence that tube could indeed be bent smoothly with the aid of sand.  And sure enough, there is a technique.... though details do seem to vary from person to person

  

We've got this far before...

But this time it's so much more pleasurable. This time I'm working on a proper work bench with lots of space.
Lining up and fixing down still took a good couple of hours

Parts all ready for assembly

There was no way I was going to get this done in my pokey little garage so we hired a van, threw all my trike bits in, and Hugh's bike too, and took it down to Jo's workshop