Hello Guys

May I get a few ideas for a little problem we have. We are workin on a boat and need to set about 50 very special pop rivets . . . but we cant find a tip that is even close to the right diameter for any of the tools we have.

I got a spare tip and went to drill it to size - well hello it was "harder than the hobbs of hell" and all I did was split it a little. It must be some sort of case hard on it.

How could I anneal this so I can drill it. I doubt we'll wreck it with 50 rivets even if its "soft" and a tip is expendable.

Cheers - Foster

Depends on the material. In practice, with carbon steel, you basically heat the area to a dull red (or, lower transformation point) and then let it cool slowly. Whereas with brass, you heat it to red and then immediately quench it.

I would try spot drilling the piece with a carbide drill, or, center drill first to see if that would gain me access to some softer material below the surface. What is it you are drilling?

Thanks Westpac

Its steel (the guide tip on a pop rivet tool, it sorta guides the shank and stops the head of the rivet being pulled into the gun).

I just wasn't to sure if ordinary annealing would work with modern case hardening - guess I'll just have to try it. We don't have any carbide drills in the size required (4.2 mm).

Many thanks

Heat it to red, hold it there for a while and then bury in sand and leave it cool slowly. It should be soft enough to drill our or ream then. How much do you need to open it?

quote:

with carbon steel, you basically heat the area to a dull red (or, lower transformation point) and then let it cool slowly. Whereas with brass, you heat it to red and then immediately quench it.

Just a comment---The only reason to quench brass is when you are annealing cartridge case necks and you quench to stop any annealing of the base of the case. If you are just annealing a sheet or "chunk" of brass it makes no difference at all whether you quench it or not, once the brass reaches annealing temperature it will be soft no matter how you cool it.

If you are sure that it's case hardened, you can use an oxy acetylene torch to heat the area you want to drill.

Get it red hot and very slowly retract the torch allowing the area to cool over roughly a minute...

This is all you really need. Burying it in sand works well too.

4.36 mm equals 11/64"

Where I am at in the States, you can buy a 11/64 carbide masonry drill bit for $3 and change. USing that with a few squirts of oil should get you through.

Another way of annealing is to simply bury the item in the coals of a fire and let the fire go out overnight. It will be soft in the morning. If your item is delicate you can fold up an "envelope" out of thin sheet steel (can't use aluminum flashing because it will be gone in the morning) and put it in that first, but personally I do not think you'd need to bother with doing that for a rivet gun tip.