How To Reduce Spring Length!!!

[Nathan1991 25]

Good evening people,

 

I would just like to ask everyone, what is the correct way to reduce the length of a mainspring,

In the past I have started by using a dremel to remove the coils then using a blowtorch collapse the last coil before quenching in oil and finish. This is how I shortened my last spring but after about 50 shots it snapped, maybe just bad luck but it may have been caused by the heat from the blowtorch interrupting the molecular structure of the steel. On the other hand many people including davyt63 use the same method as me and he didn't seem to experience any unwanted consequences.

 

Any advice welcome, cheers peeps

 

ATB Nathan

[barrywhite 282]

Look up hardening and tempering high carbon steel .this is about temps different steel is different temps ...to make a coil spring the hole spring has to be heated to 850c every bit then cooled rapidly every bit ..that is called hardening the spring is very stiff at this point and can snap very easily the spring has to now be tempered ...by heating to 300c and cooled rapidly every bit of the spring at the same time .you now have a spring .any heating of the spring will change this setting .if a small area of the spring is heated then the properties of the metal will change .If a small area of the spring is heated and bent into shape then the hole hardening and tempering process has to be done to the spring again .To shorten springs it seem weihranch just cut the ends of that is why I believe they do this .I would try to get the correct spring for the gun an old style one not xs or square section if you are that bothered .I could be wrong and if I can learn how to shorten a spring better than I know I will be happy because having a hacked of spring in a gun pisses me of .

Edited March 28, 2014 by barrywhite

[Nathan1991 25]

Thanks Barrywhite, what do you think about the collapsing process and is it needed at all? Some say not, but others swear by it. I have recently bought a Titan xs for my hw35 and I'm worried I will encounter piston slam due to the 35mm stroke compared to the hw80 with a much larger 80mm stroke. The reason I bought the Titan is because out of all the reviews the vast majority would recommend them and I have a hft comp in April so it needs sorting

 

ATB Nathan

[barrywhite 282]

I did have a square section spring in my hw 35 a long long time ago .but I did change it for a standard spring later .if you need a spring press to get the spring in the gun I would say it is to long .I was able to get the spring in and out of my hw 35 wearing leather gloves in case ,I never needed a spring press .It took a little effort but it was not to bad .With the square section spring the gun stayed together by luck I would say .As I have said I cannot see how collapsing a spring the way it is shown can work .If the spring still works and stays working it is luck .I have just cut 2 springs in my life 1 in a small old german air gun it was the only spring I could find that worked fine the other was a xs spring in an omega ,it was the correct spring for the gun but I may have taken 5 coils of the spring .but for that spring I made a little metal top hat .I would not worry about cutting a spring that was to strong, smoothing of the burrs and putting the cut end in the piston .if you put a polished washer in the piston that may help with the sharp end .or put the sharp end on the spring guide if its metal .?????? but I would not heat the spring never I told you that you would get a problem .

[Skot Ruthless Teale 1,701]

Davyt63 shortened a vmach mainspring for me and since then I have had it in 3 different rifles and its still bang on after firing at least 3000 shots. and he mirror finished the spring ends aswell whildt he was at it .. something vmach had not done. not much to ask from a 'tuning kit' is it, polished spring ends ..!! especially when they charge £ + for a spring, seal and guide tophat and a little tub of grease and a few washers that you don't even need!!! lol rant over sorry lol

Edited March 29, 2014 by Skot Ruthless Teale

[pernod 466]

Theres a verminhunter tv video on youtube where davyt63 shortens/colapses a mainspring. Easy to follow. I done my poorly finished 97 mainspring. Still working perfect after thousands of shots. Give it a go.

 

pernod

[Nathan1991 25]

Thanks guys,

 

Still mixed opinions though in theory I can see how heat treating one end would disrupt the tensile strength of the steel resulting in a weaker composition, but on the other hand people who have done it this way have never experienced any unwanted affects. When I shortened the previous spring in my hw35 it was amazing until it broke, interestingly the broke occurred 6 coils in from the weihrauch end :/ so I am confused

 

ATB Nathan

[nicknack 0]

I have chopped rings off and then ground flat on a wheel ...spending time here is worthwhile . Polishing is also nice to get a finished result .....but the the best result is to heat the end and get it completely flat again . I have never bothered mind . You will as more learned metalurgists here relate , run into weakening the spring . I have always wondered about snapped springs . I remember seeing one of the big Tuners show in an Airgun World article how he did this - and he did reheat the spring , ...also mentioned 'linishing ' which I forget what was involved - it seemed to be to polish again until heat builds up [ or maybe thats the name for reheating ? ]