This is High Quality Stuff.
Thanks to a lead on the 7mm E-group I discovered this American company, which manufactures some useful stuff. I ordered these rivets from their website on the 23rd May. They E-mailed me confirmation of order within hours and dispatched on the 24th. They arrived here on the 27th. Impressive service.
The rivets themselves come in a variety of sizes and materials and are exquisitely machined.
All I have to
do is drill an appropriate sized hole, fit the rivet and solder from behind.
I shall be experimenting with them when next I build an engine for myself I have 0.4, 0.5, 0.7 & 0.8mm head sizes and will report on their use in due course.
I used some to embellish the Mitchell 517 No: 1475