Saturday, 12 January 2019

SQ4 Chainguard again

After months of messing about, I have attacked the Square Four's lower chainguard again - mainly after having seen the proper version.

The thing I realised is that in about 1951 the pillion footrest hanger, to which the chainguard is attached, moved below the frame tube - all previous years have them above the frame tube and of course the chainguard bracket has to suit this arrangement.

Also in 1951 came the stop switch, mounted on the chainguard. The chainguard now looks like this, and it was used from 1951 right through to the end:

It's also much shorter than I previously had it.

What I hadn't bargained with was the effect this has on the brake rod. With the brake light switch mounted in that position, clearance to the brake rod is minimal if indeed there is any clearance. I already had issues with the brake rod, which was running in as straight a path as possible; those of you with Square Fours (prior to the arrival of the brake cable) know that this area is not very satisfactory - there is little room between the stirrup and the brake plate, and the chain adjuster is on there too.

No, the only answer is to bend the brake rod more than desirable and a few hours with the mighty Rothenburger saw that happen. Some pictures:

Straight run past the chain adjuster

Kink around the adjuster and over the stirrup

Significant bend toward the lever

So there you have it - the grey primer shows you that this is not finalised yet and I am none too happy with the rear brake - of course the bend in the rod has introduced a lot more play in the pedal before the brake engages. I might try this again...

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