22.10.21

22.10.2021 Barrel nuts.

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Friday 22nd 43F, heavy rain continues.

I have finally discovered the Danish name for a barrel nut. Tværbøsning.

These are useful fasteners where one wants a strong, mechanical fixing. Far superior to a wood screw driven into the vulnerable edge of plywood. The problem is a chemical reaction between different materials and rust. Almost all of these nuts are flash electroplated zinc over steel. Which are already rusting in the bubble pack in poor storage conditions. Using these out of doors is just asking for trouble if one ever hopes to dismantle the fixing. 

Stainless steel threads have a tendency to stick. Even when stainless nuts are used. Brass barrel nuts make sense. The material is easy to thread and machine. Now insert the bolt through an aluminium bar. The combination of different materials can lead to staining and electro-chemical reactions. 

Aluminium barrel nuts would work. Provided the thread size matches the loads.

Brass barrel nuts do not pop up in searches within Denmark. [Using the correct terms and avoiding AliExpress' online crookery.] So I ought to make my own. It is too wet to work out of doors. Not too wet to reach the workshop. 

I made an M10 barrel nut from a scrap of 16mm brass rod. I would have preferred a larger diameter to provide more shoulder to resist the considerable compression loads. 20mm rod?

 

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