Burrell Passenger Trolley

Chassis

Trolley Intro

Trolley Superstructure

Testing the welding jig in the workshop Insert; joint prepared for welding Using the jig to align the final section of the frame The final piece tack welded in place

Week Beginning 2nd October:  The basic chassis is a 1800x300mm rectangular frame made from 30x30 x 3 mm box section steel tube.  As I am a novice welder I decided to practice by making a trial joint.  I 45 degree mitre cut two short pieces of tube and prepared them for welding by chamfering the edges to be welded.  I have a large angle plate and I used this to hold the tubes in the correct position for welding. 

With the tubes securely held I found it easy to produce reasonable welds.  I tried using the angle plate to hold the long tubes for the chassis but it did not work out.  I then had the inspiration  to use the test piece to make a jig.  I welded on steel strips to form channels into which I would clamp the tubes prior to welding.

Somehow it took me over a day to prepare the four tubes for the chassis frame.  In the processes I broke two hacksaw blades and given I have not broken any for years, I was surprised.  I put the aberration down to the difficulty caused by cutting at 45 degrees to the vice.

Once the preparation was complete it did not take long to weld up the frame.  I tack welded each new piece into position using my jig.   As an addition precaution I clamped an piece of angle iron between the long sections to prevent them twisting and to hold them parallel.  With everything tacked in place I checked alignment prior  welding all the seams.  To minimise distortion to the frame I rotated between corners doing only one seam at each before moving to the next. 

As I had heavily notched each seam I was able to dress each joint flush.   I removed the bulk with my angle grinder finally finishing off with a file.  Since buying a new, quality, angle grinder it has become my tool of choice to remove large quantities of metal.

Front Axle

The most complex part of the design is the front axle incorporating Ackermann steering.  Originally I planed for the wheels to point parallel to the tow bar but after researching the Ackermann geometry I decided it was just as easy to do it properly. In fact it improves clearances and simplifies the connection of the track rods to the tow bar as they don't share the same pivot.

The stub axle consisted of a pivot and wheel shaft turned front 1"x1" solid bar to which I welded the steering arm.  Conscious of the vertical load that will be transmitted to the chassis I incorporated roller bearings above the stub axle.   It was only once I had made the first that I realised that there is a severe twisting moment on the king pin.  I had to revise my plans to do everything I count to increase the length of the pivot.  
   

Welding the king pin strut in place
 

Trial fitting the axle to the chassis

Friday 13th:  I have been busy all week on the front axle completing it today.  Looking at the picture below  there does not seem to be that much differences to Monday's however think I have made progress as I now have one of the more difficult aspects behind me.

Saturday: Excellent progress the chassis is nearly finished!   

I fabricated the back axle from 30x5 and 25x5mm steel strip welded into a H section.  At its ends I welded stub axle similar to the front though without the pivot.

I welded the axles to the chassis frame using standoffs to set the distance.  In addition I have added some diagonal bracing  and plan to add more to strengthen the chassis and prevent it twisting.  I hope I will not regret making a long ridged chassis - time will tell.

The completed chassis