Did you get it from Amazon or ebay or who? The vintage turn signal switches had clamps, but better looking than a modern radiator hose clamp you probably have.

Options:
1. Send it back, if Amazon or friendly vendor, and buy a used original. Don't buy chrome unless you want chrome. Painting it is a PITA.
2. Cover the clamp with heat shrink tubing. Shrink it or leave it unshrunk, whatever looks best.
3. There are some nice looking exhaust clamps and industrial pipe clamps/hangers if you can get them to fit the switch body.
4. There are all manner of wide non metal cable straps with low profile heads. Not sure those with be tight enough.
5. There are some specialty radiator hose clamps/vintage radiator hose clamps/racing hose clamps that may suit you.
6. Old piston rod end or just the cap.
7. All kinds of steering column clamps/collars for mounting a steering column.

Many of the above may need "modified" a little. The switch body may need modified a little. Send good clear pic of it, if you get into that mode, for suggestions.


Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn