Sunday 27th October
It has been a long time since I have been able to get anywhere near the trike due to other commitments and the weather. But today was a lovely bright, cool, calm day (instead of blowing a gale and teeming with rain). The trike was unusable with the existing front-boom clamping arrangement; the 4-way wedge operated by a hidden slide mechanism. If you put any real pressure on the pedals, the boom pushed out and away from you. It had to go.
This presented something of a problem, the boom insert is so much smaller than the square tube of the main keel that there was more than 3mm of space in both side-to-side and top-to-bottom between the insert and the keel-tube. To begin fixing this I looked at a couple of options:
- Cut-down long-nuts on one corner of the keel tube and bolts pushing the corner of the insert towards the opposite diagonal corner.
- Pack out the insert tube with external plates welded on to increase its width so that a standard “pinch-bolt” arrangement can clamp the tube.
Having a gap of 3mm or greater on 2 sides of the boom insert all the time sounded like a recipe for collecting rainwater to me so I rejected option 1 and cut some pieces of 1.5mm plate to weld to the sides of the insert.
Shown below are the two pieces of 1.5mm plate inserted into the keel tube along with the front boom so you can imagine what a terrible loose fit it had been.
I am NOT sure whether to just weld these plates on every few inches (top & bottom) or to try and weld along the entire length of the plate’s edge. A Continuous weld might induce a warp/bend/twist in the insert tube so for the moment I have just welded every few inches.
Here it is in the keel tube, the fit is not bad at all. I may opt to fully weld these edges as equal and opposite welds ought to balance out in terms of inducing any bends in the insert tube.
The next task will be to make some pinch-bolt sleeves and weld them onto the underside of the keel and cut a slot to form a clamp arrangement.
That's all for now.