Two piece poppet valves

[steamer]

300 series stainless steel is Austenitic Stainless steel, and does not harden by quenching.   The only way to harden it is to work harden it.    Red heat will anneal it.   303L machines nice as it's got more carbon in it    304 and 316 are miserable to machine, but are more corrosion resistant.

400 series is a martensitic steel that will respond well to heat treating....Made some great Ultra precision machine spindles from 440C...

I like the 2 piece idea here.....getting small diameters really consistent is no small task!, but centerless ground pins are everywhere.

Dave
 

[CI]

I am told that using a material like Class 40 gray iron for the valve head and a corrosion-resistant ground stainless for the rod gives the best of both worlds, ie: strength and corrosion resistance where it was needed, and an excellent wear and impact resistant material at the seat.

I don't have experience with making valves yet, but it won't be long, and I will be trying the two piece method.

I have seen a video of someone using a stainless rod, and a cast iron head, and they heat the top of the rod with an oxy-acet torch, and then peen the top of the rod. (can't find the video now).
It is a quick process, and does not significantly heat the head or the lower end of the rod.
I don't think you would want to try and siver solder a cast iron head to a steel rod, since cast iron is prone to cracking unless preheated and then cooled very slowly.

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[Dave Otto]

I have seen a video of someone using a stainless rod, and a cast iron head, and they heat the top of the rod with an oxy-acet torch, and then peen the top of the rod. (can't find the video now).
It is a quick process, and does not significantly heat the head or the lower end of the rod.
I don't think you would want to try and siver solder a cast iron head to a steel rod, since cast iron is prone to cracking unless preheated and then cooled very slowly.

Did you not see the photos that I posted above? Not necessarily SS stems but the process is the same.

Dave

[CI]

I did indeed miss that.
Thanks for the pointer.
 

[stevenz]

New to the forum and noticed a question about the fit or clearance for soldering as well as the response that clearance is required. I recalled that Harris published some info on clearances and their alloy catalog includes clearance recommendations for their various products. No idea if there are well understood clearances but this might be a place to start.

[CI]

My understanding is that less is more when it comes to silver solder clearances, ie: a thin silver solder joint is much stronger than a thicker one.
And of course if the fit is too tight, there is no place for the silver solder to flow, so it just sits on top outside the joint.
I have done some silver soldering, and it is a viable high-strength method to connect metal, but boy does it require a lot of heat.

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[petertha]

I found this to be a useful guide for stainless, well, the more common N-Am designations

https://nickelinstitute.org/media/1814/stainlesssteelsformachining_9011_.pdf