Tempering Rivet Snaps

I need to make a couple of narrow 1/16" rivet snaps to get into awkward places.

I was going to use silver steel and harden it out, but in water or oil? And what to temper it down to?

My only previous experience in similar heat treatment has been when making small reamers out of silver steel - but these were left hard.

Hi Nick, never made any of these but used a lot of SS for tools cutters etc personally I would harden in oil, nice cherry red, clean up and degrease, final clean with fine new emery then temper to a dark straw in subdued DAYLIGHT -- artificial light gives a false colour. This should be hard enough to resist wear but tough enough to withstand shock.

John

Are you only dealing with copper rivets or do you want to use them with steel rivets as well? That might have an influence on your choice of material.

I agree with JohnF with the dark straw, or even a little past that into blue-purple. They need to be tough and not brittle, rather than hard.

In the first instance copper, although I can see a future need for soft iron/steel, so I was planning ahead and trying to avoid remaking them in the future

As stated above, Dark straw is correct, or 245 degrees c you want them tough and hard but not brittle. This tempering in all hcs tools is a compromise between these factors.

When I made the rivet snaps for my traction engine wheel spokes I used silver steel. Hardening was done by soaking at 800°C and quenching in brine. It is critical to vigorously agitate the part when quenching. Otherwise you don't get anything like full hardness. I tempered at around 240°C. The snaps have been used to close 3/16" steel rivets using a flypress, so they have a fairly hard life:

After 150+ rivets the upper snap has a slightly mushroomed head, but it should last the remaining 100 or so rivets. If I was making the snaps again I'd reduce the tempering temperature by ten degrees or so. The flypress is probably less of a shock load, but the forces are much higher, than using a hammer. My initial riveting trials with a lump hammer failed to close the snap head properly, whereas a few good swings on the flypress did the job:

Andrew

Thanks - and Andrew I envy your perseverance! Thank goodness none of my current projects include so many large rivets!!!

Andrew

Just looking at the wheel rim photo above, it would appear to have slightly bulged the rim inwards on the two rivets nearest the edge. Or I could have just imagined all the above !!

I reckon you will have got some really good strong joints if the rivets have expanded with such outwards pressure in the holes like that.

Phil

That's correct; same on the front wheels as well:

We can safely say that my wheels aren't pretty, but they're not going to come apart.

Andrew