Spring too soft

[sydney]

Hi using steel from Dixie that i believe is 1075
    They say to temper at 740 deg but too soft
     tried at 675 and still soft
     Any ideas??
      Thanks   Sydney

[bnewberry]

Are you hardening this before you temper?

[sydney]

Yes   To a bright orange--quench in canola oil
        using a lead pot to temper
        Sydney

[Scota4570]

Does a file skate across it after the first quench in oil?? 

What you are doing is how I make springs out of known 1075.  I draw it to 750 in lead. 

[sydney]

Hi yes the file skates on the spring
    i tried at appox 740 using my lead pot
    Sydney

[smart dog]

Hi Sydney,
What do you mean by too soft?  Does the spring bend and stay bent or take a set or does it work as it should but just has no power?

dave

[sydney]

Hi the spring takes a set--also has no power
    No snap to the spring
      Sydney

[Daryl]

Maybe lead thermometer is out of whack. Maybe a toaster oven with a temp gauge would be better for temering. That's what Taylor uses.
Sorry, I do not have a lead thermometer to loan you.
I'm sure he would loan his unit, or you could do it over having a beer (he's got a new bottle of single malt) in the shop?

[Dphariss]

I think you are overheating the part in tempering.

[smart dog]

Hi,
Then the problem is clear.  You have not hardened it successfully regardless of what you did.  Perhaps it is not 1075 steel  or you did not heat it enough. 

dave

[D. Taylor Sapergia]

Sydney:  show us a picture of the spring.  If it is a claw type mainspring, I have material that I received from Bob Roller that makes great springs, and I heat treat it just as you  are doing...I'll give you a piece for a new spring.  Unfortunately, the single malt is all but evaporated, but I still have enough to serve Daryl tomorrow night at supper...then it's gone.

[sydney]

Hi i think i am not getting the spring uniformly before the quench
     Thanks for help
      Sydney

[Scota4570]

IF the thermometer is in question get some of these:

https://www.mcmaster.com/temperature-sticks/