N/A Spring modification, heat treating

[Hold_Over]

Sometimes in the process of tuning it is necessary to cut a spring and heat the last coil to collapse the end before flattening. I have seen several posts on here about heat treating after, usually with regard to what to quench in after. Water vs. Oil etc. I would question the validity of doing this.

I say this due largely to the fact that metal is conductive. The idea is to heat, quench and harden the coil you have just collapsed. The reality is if you apply heat at the first blue line in the photo, you are also applying heat to the closest coils of the springdown to the second blue line. Those coils will not be at the ideal temp for hardening, and will be effected by the process. Potentially creating a pattern of hard at the end, a different unknown hardness at the 2nd blue line, and then a return to the factory hardness once at a distance that remained cool enough to be unaffected. Vs an untreated spring that would have a soft/annealed end, tempered at the 2nd blue line. And then returning to factory hardness in the unaffected portion. Which would be a natural progression of increase, and potentially better transition.
I won't ramble on forever before leaving this out for discussion. However, I am a guy who has built my own coal fired blacksmithing forge, and made knives that require heat treat for hardness, and process for tempering to be able to hold an edge without becoming brittle at the apex. My question on this process is rooted in the idea that I would never spot heat treat a knife, and expect good results. You heat the entire blade before the quench to ensure uniformity. To restore proper heat treat in the spring it should be all, or none IMHO.

 

[Sqwirl57]

I heat treat all of my springs when I collapse or cut a coil. No idea if I'm doing it exactly right but I'm following the directions I saw on YouTube. I’ve never had one break except for a factory HW spring and I distinctly remember thinking something doesn't look right here. It broke immediately when trying to compress it back into the gun. The rest have gone thousands of cycles (a couple are well over 10k) without issue

 

[Hold_Over]

I expect there is zero positive impact generated by heat treating just the end coil. The fact you have gotten good longevity suggests there may also be zero negative impact given such a small amount of space being effected. Also that being in the compressed, essentially non-working portion of the spring. This may be an unnecessary step promoted by someone trying to justify high labor rates with how thorough their process in tuning is.

 

[boscoebrea]

Some would Put a wet towel on spring or the heat absorber piece ,simple to do. You do not need to be eladorate,just careful.

 

[Sqwirl57]

I expect there is zero positive impact generated by heat treating just the end coil. The fact you have gotten good longevity suggests there may also be zero negative impact given such a small amount of space being effected. Also that being in the compressed, essentially non-working portion of the spring. This may be an unnecessary step promoted by someone trying to justify high labor rates with how thorough their process in tuning is.

Heat treating definitely isn't the reason tuning is expensive. Thats probably one of the fastest parts of it. A couple minutes and done. Making guides and taking the gun apart multiple times, plus making sleeves, adding buttons or piston rings, and de-burring the tube takes most of the time.

As far as my understanding of why it gets heat treated goes, it isn't necessarily to strengthen it but more so to unweaken from the original heating, collapsing, and flattening

 

[Hold_Over]

Some would Put a wet towel on spring or the heat absorber piece ,simple to do. You do not need to be eladorate,just careful.

The towel acts a heat sink, which would in theory concentrate the unknown transitional hardness to a very small area. Potentially even worse as far as creating a weak point in between the end and factory specs. The use of a heat sink is generally to heat a siezed threaded component, and not destroy a seal in close proximity, not a spot hardening techique. Various different steels require very specific hardening processes. If you compare the very straight forward process to harden 1095, to a complex process to that of 154cm which requires a very temp controlled series of heating and cooling cycles. You will see there are too many unknown parameters for someone to be doing a comprehensive job in the garage with a spot treatment. What kind of steel, what temp/oil or water did the factory quench in etc.? Is there a tempering cycle that needs to be followed?
I have no issued about being thorough when justified. Cut a hole, de-burr the hole. Get a justifiable cause and effect that dictates process. I just don't see it here.

 

[Hold_Over]

Heat treating definitely isn't the reason tuning is expensive. Thats probably one of the fastest parts of it. A couple minutes and done.

I am not suggesting it is labor intensive. More of a wow marketing factor to those who would pay the bill,and aren't mechanically inclined to take on tuning themselves. Playing with fire looks impressive, even if there is no distinct advantage.

 

[Mycapt65]

This should get interesting. I had one spring break at the color change after closing the end. It was about a coil away from the end. I've always let my springs air cool after heating them cherry. I did experiment and water quench one of mine but I'm not sure if the one that broke was the water quenched one. I suspect it was.

After closing the end and air cooled I continually water dip the spring end in water or oil to keep it cool while grinding. I take it in slow steps to not overheat it. It's the same method I used to sharpen twist drills. The drills would be garbage if you got them to hot while sharpening them. Water worked about as good as oil for them. Just not as smokey. I believe the idea was NOT to change the temper of the bit with too much heat.

 

[Hold_Over]

This should get interesting. I had one spring break at the color change after closing the end. It was about a coil away from the end. I've always let my springs air cool after heating them cherry. I did experiment and water quench one of mine but I'm not sure if the one that broke was the water quenched one. I suspect it was.

After closing the end and air cooled I continually water dip the spring end in water or oil to keep it cool while grinding. I take it in slow steps to not overheat it. It's the same method I used to sharpen twist drills. The drills would be garbage if you got them to hot while sharpening them. Water worked about as good as oil for them. Just not as smokey. I believe the idea was NOT to change the temper of the bit with too much heat.

Correct, when sharpening the drill bits the idea is to never exceed a temp that changes the hardness and create a need to redo anything. When collapsing a spring you have deliberately exceeded those parameters to make the metal movable into the new shape.

 

[Sqwirl57]

This post started me down a bit of a rabbit hole where I found this. My simple brain can't find any fault in the logic. The next comment recommends 375°

Granted this is to heat treat newly made springs which doesn't really apply to springs purchased from places like ARH or Vortek. Just thought I'd share

 

[Hold_Over]

This post started me down a bit of a rabbit hole where I found this. My simple brain can't find any fault in the logic. The next comment recommends 375°

View attachment 448048

Granted this is to heat treat newly made springs which doesn't really apply to springs purchased from places like ARH or Vortek. Just thought I'd share

This says to "temper" which I believe. Same as with a knife blade where you could use an oven. After the initial hardening, you would use a tempering process to remove brittleness from the refined edge before sharpening. It is basically a controlled mild softening that adds to durability particularly with a striking edge to eliminate chipping while in use.

 

[dizzums]

i can tell you from experience, if you dont have the heat 'exactly' right on a spring, it will snap in short order when put into use .. barring being an expert your best bet is grind the end as flat as reasonable, polish it a bit and call it a day ..

 

[Mycapt65]

i can tell you from experience, if you dont have the heat 'exactly' right on a spring, it will snap in short order when put into use .. barring being an expert your best bet is grind the end as flat as reasonable, polish it a bit and call it a day ..

Unfortunately you have to heat the spring to close the end. Grinding it flat alone is not an option.

 

[Hold_Over]

I've always let my springs air cool after heating them cherry.

This process would anneal this spring end, essentially removing hardness from that portion. The quench is designed to cool at rapid rate causing the molecules to shrink back quickly into a denser pattern creating hardness. I would be interested in the shot cycle with air cooled vs quenched. Assuming both were done in a way that longevity was not effected, the air cooled softer end of the spring should in theory work a bit as a vibration damper.

 

[JEFFPPC]

A fellow in our group tunes by cutting springs. Dresses with a file only. Those guns shoot extremely well.

 

[Mycapt65]

This process would anneal this spring end, essentially removing hardness from that portion. The quench is designed to cool at rapid rate causing the molecules to shrink back quickly into a denser pattern creating hardness. I would be interested in the shot cycle with air cooled vs quenched. Assuming both were done in a way that longevity was not effected, the air cooled softer end of the spring should in theory work a bit as a vibration damper.

So what's the answer? Air cool and remove the hardness or quench unevenly and possibly have failure at the areas that aren't at the proper temperature for quenching? I'm not sure what to do now.

 

[Sqwirl57]

So what's the answer? Air cool and remove the hardness or quench unevenly and possibly have failure at the areas that aren't at the proper temperature for quenching? I'm not sure what to do now.

I'm thinking people should just keep doing it however they have been doing it if it wasn't giving them issues before. This is like the whole "what lubes are best" argument that happens every other month. Theres are many ways to skin a cat. Some may be a bit better but if the results are the same.... I'm fairly certain that half the things we do to springers don't even matter anyway but if they don't hurt and you like doing them, does it really matter?

 

[JimBentley]

I was told by a former tuner and maker of springs to just cut the length and collapse the last coil by heating it. There is no need to harden it. It's worked for me on a few dozen springs that have lasted thousands of rounds.....so far.

 

[Hold_Over]

I was told by a former tuner and maker of springs to just cut the length and collapse the last coil by heating it. There is no need to harden it. It's worked for me on a few dozen springs that have lasted thousands of rounds.....so far.

This right here makes the most sense to me from mechanical perspective. As mentioned in the first post, would give you the first coil essentially annealed/soft metal , moving to something that has been tempered, and finally back to full heat treat from the factory. Likely the best scenario giving a mild vibration damping effect at the contact point followed by progressive hardness.

 

[KWK]

I was told by a former tuner and maker of springs to just cut the length and collapse the last coil by heating it. There is no need to harden it. It's worked for me on a few dozen springs that have lasted thousands of rounds.....so far.

That is what Tinbum suggests.
But it might be better to listen to the AGN metalurgists instead