Friday, 5 April 2019

Welding Nuts

As you will know, the swinging arm Ariels make use of Spire fasteners and matching screws in various places, which look a lot like blunt self tappers. These appear in the rear mudguard and the seat base. Additionally, the bikes use captive nuts in sheet metal cages (I made one here) in the headlight and in the chainguard.

Of course, the captive nut in the chainguard was missing. I thought about making one, and having fiddled around for a while making a 5/16" one for the headlamp, I wasn't about to make a smaller (1/4") one for the chainguard that no-one would ever see, so I decided to weld a nut in.

Now the tab on the chainguard is not so large, and I wanted something larger than a conventional nut to weld to, and secondly I wanted to make sure the thread was in the centre of the square hole in the chainguard, so I came up with a special nut, designed to be welded in:


It's turned up from a piece of 3/4" round bar on the lathe:


It's got a 0.35" diameter journal to fit into the hole, and a lead in chamfer to a 1/4" BSCy thread:


The back is also chamfered, to allow me to make a fillet weld easily:


I'll make some 5/16" ones for the mudguard and seat.

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