Thread relief on tenon

It is my understanding that most actions can be treated. The ones that cannot be treated are 416 SS actions (Stiller et al) and cast actions such as WBY and Ruger. I had my Defiance Machine action treated but it is CM steel. I had another one treated and the customer took it to have it Cerakoted and the guy grit blasted all the black treatment off and Cerakoted it black!:confused:

This isn't a thread about treatments so I will stop here.
 
I sure would like to see a picture of something that has been treated. Id like to see just how dark the finish really is? I really really like the look of CM bat actions, so much so that i just ordered one. Lee
 
skeetlee said:
I sure would like to see a picture of something that has been treated. Id like to see just how dark the finish really is?
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Lee, here's a die of mine that was treated.

Treated die (lt.) and untreated die (rt.) -Al

d1-1.jpg
 
Here are a few more photos for you Lee:

DSC_0251.jpg

DSC_0253.jpg

DSC_0213.jpg

DSC_0097.jpg

DSC_0073-1.jpg


As far as I know, if you contact Joel Kendrick and have a barrel or action to send in, he is going to send you to me unless you have a Type 7 FFL. MMI now only processes barrels for firearms manufacturers and they have a minimum batch fee of $200. If you want 1 barrel done, you can ship that to Freedom Gunworks to be included in the weekly batch. Turn around is typically 3-4 weeks and the cost is $75 per barrel. This post is not to serve as an advertisement for Freedom Gunworks but more as a public announcement for those interested. At one point, I was named the official gunsmith for MMI, as far as I know that hasn't changed.

As for what Butch said, we're seeing a 100% increase in barrel life. I can't claim 3 times the barrel life, but in my experience that would be more caliber specific than anything. The black discoloration is a side effect of the process. It is a thermo-chemical induced hardening process. A barrel COULD be set back after it's been treated, but it would quickly dull a reamer. IMO, it be advisable to replace the barrel vs setting it back.

As for blasting the black off and "cerakoting" it, nothing wrong with that. I have a few theories on rust. Rust is a decay of the surface material, the metal erodes, the brown we associate with rust is the waste evidence of this reaction. If that metal is so hard that the level of degradation is minimal, corrosion or "rust" will be minimal. Surface discoloration generally. I've processed a part, blasted it, then observed the rusting characteristics. With 4140 carbon steel, surface rust will form overnight. On a processed part with the "black" blasted off, even with excessive sweaty hands handling, there is no rust formation. After prolonged exposure, discoloration might appear, but that has been the extent of it. I'm not advocating this to be the norm, just something I have noted in a very small test sample (6" part, but only 1).

I'll answer what questions I can.
 
Here is a poor picture (took with my phone)-but illustrates threading up to shoulder. Done on Victor 16x40 lathe at 320 rpm manually. I use a full form ISCAR Threading Tool

barrel_threads.jpg
 
Here is a poor picture (took with my phone)-but illustrates threading up to shoulder. Done on Victor 16x40 lathe at 320 rpm manually. I use a full form ISCAR Threading Tool
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It still cut a relief. In the heavy duty world, thats where the part will fail. Setting it back won't look pretty either.
 
Looks pretty darn nice I think. Relief? Everything has some somewhere. And for strength, I'd say there's about zero chance of a failure.

Photos show a lot of sins... Them's nice threads.
 
And for strength, I'd say there's about zero chance of a failure.
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A thread like that will last forever in a barrel application, but for a high stress application, that threading up to a shoulder is the worst condition that you could leave it in. It will break right in that relief groove, that the insert cut against the shoulder.

Those threads are more for looks than a useful means to add strength to the assembly. Your only using 4-5 threads, and you don't want them to be on either end, especially if either part was threaded on a CNC.
 
TRA said:
A thread like that will last forever in a barrel application, but for a high stress application, that threading up to a shoulder is the worst condition that you could leave it in. It will break right in that relief groove, that the insert cut against the shoulder.
TRA
Those threads are more for looks than a useful means to add strength to the assembly. Your only using 4-5 threads, and you don't want them to be on either end, especially if either part was threaded on a CNC.
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There is no relief groove there! The small cut at shoulder was made by the turning tool and is no deeper than the root of the thread (.990 inch). Do the calculations as I have! Those threads were done manually-not by cnc.

Not sure how you are "modeling" threads to make the statement you made. Have done lots of engineering and design of threaded joints for pressure vessel applications.

Jim
 
Jim Borden said:
There is no relief groove there! The small cut at shoulder was made by the turning tool and is no deeper than the root of the thread (.990 inch). Do the calculations as I have! Those threads were done manually-not by cnc.

Not sure how you are "modeling" threads to make the statement you made. Have done lots of engineering and design of threaded joints for pressure vessel applications.

Jim
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I am sure a video of the threading operation at 320 RPM is in store for us skepticals!!
 
In my mind if jim said he did those threads on a non cnc machine then that just goes to show us how talented he really is. I have no doubt to his claim. Jim makes some nice stuff and this is just another example. Looks darn good! I believe I will be making a relief cut when I get up and going. Lee
 
JIm,

I'd appreciate it if you'd tell us how you set up and time the end of the threading pass.

Thanks.

A. Weldy
 
Thanks Jim

Will be looking forward to seeing your method.

On the other hand, if Jackie can't do it, I probably shouldn't even think about.

A. Weldy
 
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