I thought this next step would be a breeze and would only take me 10 or so minutes. I could not of been more wrong...
The spacing between the front and middle wheel is closer than the middle and rear wheel so the coupling rod will only fit one way round. It does mention this in the instructions so as long as you read the instructions you should not get caught out.
The process to fit the rods is quiet a simple concept but takes some time to complete.
Before you even think to fit the rods go get yourself a good quality round file that will fit
through the holes in the coupling rods as this is essential.
To start you fit a 5BA steel washer over the crank pin on the rear wheel, you then slide the rod
onto the pin and using a short crank pin bolt fit the rod to the front wheel fitting another
5BA washer between the rod and the outside crank, do not worry about the middle wheel at the moment.
You do the same for the other side. Now the fun starts.
After fitting both coupling rods I could hardly move the wheels at all. The reason is that the crank pins are slightly off centre with the holes in the coupling rods and so when the wheels rotate and outside cranks are pointing either forward or reverse they bind.
To fix this you rotate the wheels until they bind, you then look which outside crank is pointing
forward or reverse, then remove the crank rod from it and using the round file slightly elongate the
hole on the front of the crank. You then refit it and try again and keep doing this until the wheels
rotate freely and no longer bind.
This took me about 2 hours to achieve.
Maybe I was too careful and filled too small amounts of each time but I did not want to make the
fitting of the coupling rods too sloppy.
Now that the front and rear wheels are connected and not binding it is time to connect the middle
wheels with another 5BA bolt and washer and go through the same filing process again.
This only took me about an hour to achieve.
Below is a close up of the frame with coupling rods fitted and then a picture of my 2 year old son
Thomas checking for binding points with one of my cats 'Cindie' stalking the chassis behind him.
