Annealing: Settled on a method with highest repeatability - using garage tools

[Alantoo]

But I have three cases sizes to deal with and they correspond to 3/8", 12mm and 14mm/9/16".

Yes understood, and what you have done looks great, I hope my comment didn't come over as negative in any way...it was intended as a heads up to a simple solution for others with 308 cases.

I ended up using the 1/2" drive hex socket key because just like you, I found using a 1/4" hex to square drive adapter with the case held in a ordinary socket was very wobbly at the square drive point, I guess one could use a 3/8 square drive hex socket key for your smaller cases, but you would still need to make your Ø14mm one. The big advantage of making your own is you can make the hole that much deeper which supports more of the case and keeps it spinning truer.

At the time I was looking around for a cartridge case chucking device I was at home with odd socket sets rather than at the forge 6 miles away where there is a lathe or two which would be very easy to drill a bar at one end and turn down a drill chuckable stem at the other, hence my KISS solution.

For future reference...

If your Ø6mm drill is producing slightly oversized holes it may be because the cutting edges are dissimilar leg lengths...it is quite a useful ploy if you actually want a clearance hole to deliberately grind them to an offset centre...

Another possible remedy to a loose bar in a hole is to tap in a series of centre punch marks or chisel cuts around the spindle...the little levee thrown up around the dot or dent is sometimes enough to fill the gap and take out the rattle...even if just to centralise while the glue goes off.

Alan

 

[Ozalid]

My understanding is the brass needs to reach around 500 degrees to anneal, I just hold mine in my fingers over one of the gas cooker jets, by the time the heat has conducted to my fingers the case neck and shoulder is coloured, I then drop the case into a bowl of water, job done.

 

[25 Sharps]

A while back I invested some time in building a Skippy-style annealer. As with all projects, the journey is half the fun. But what I soon realised was that the annealer I could make was not going to give AMP performance. And it would be a faff to operate.

So...what I have done instead is perfect the method by which I anneal using a cordless drill cupping the case head in a ratchet socket of appropriate dimensions View attachment 162232 . I am 100% sure that this method gives repeatable results.



What makes this method accurate is a multi-way check using several methods found on SD and YT. Vitally important: perform annealing in a darkened room. The iridescence of the brass is subtle and best viewed in black out. Second discovery: if your burner is too cool, the whole case gets heated by the time the neck is ready. Better to run a hot flame and have lightning responses to the colour change described below.

1. I used Alan's soap test to verify that the neck had reached annealing temperature whilst being rotated in flame. Repeat tests showed that soap threshold is reached when...
2. ...inside neck colour switches from black to black-red View attachment 162234. There can be no lingering in the flame past that point because test runs reveal that in just 2 secs more colour changes to...
3. ...candy-apple red View attachment 162235 and that spreads down the shoulders View attachment 162236in sub 1 sec thereafter at which point...
4. ...removing the case from the socket with bare fingers is uncomfortable. Burnt fingers/hot socket means the brass was heated too long. Uniformity of finished product confirms method View attachment 162239

This is and has been the standard way of doing it for some time now….

 

[zambezi]

Interesting YT clip produced by AMP Annealing: They demonstrate that annealing twice [at the right temperature] does not alter the properties of the brass.