spring color

[little joe]

Have made a presentable main spring have forgot what temp. to draw it back to. Can anyone help?

[rich pierce]

I'd not rely on a quick temper judged by color for a mainspring.  There are 3 methods most use here: a temp controlled furnace, putting in a dish of motor oil and burning the oil off, and immersing in a pot of molten lead just hot enough to cast round balls. All rely on a soak at temp and not a torching till the right color is achieved.

[L. Akers]

I have had excellent resuts soaking a spring made of 1095 in a lead pot at 800 F.

[jerrywh]

800 is OK but a little mushy. I like 750 better.  The guy needs a lead thermometer. The casting temp for round balls is about the right temp. At least 12 minutes in the lead. 20 minutes is better.

[James Wilson Everett]

Guys,

I temper my springs made of 1095 at 810 F in a furnace.

Jim

[D. Taylor Sapergia]

I have tempered a lot of springs using a plate of copper 1/4" thick,  I drill a hole just large enough for the 'tit', without piercing the plate, lay the spring edge down on the copper, heat from beneath with a torch, slowly.  I place a small drop of oil on the plate so that when it starts to burn, I am getting close to temperature.  I bring the copper plate up little by little and watch the colours in the polished steel.  When I get to dark blue, I back off the heat, bringing it evenly up even more slowly, until the spring turns light blue, and remove the heat.  I leave the spring on the plate until I can pick it up with my fingers.
The heat treat oven, oil bath and lead bath, are better.

[satwel]

I've only done a few springs, but so far, 750 degrees has worked for me.

[Marcruger]

I thought from the topic that this thread referred to the color of flowers in the Springtime.  :-D

[Bob Roller]

I'd not rely on a quick temper judged by color for a mainspring.  There are 3 methods most use here: a temp controlled furnace, putting in a dish of motor oil and burning the oil off, and immersing in a pot of molten lead just hot enough to cast round balls. All rely on a soak at temp and not a torching till the right color is achieved.

After hardening the spring I polish it and using duck bill pliers I hold it by the stud that goes thru the
plate and then a Bernzo-matic torch with a special tip I watch the color go to dark blue and then
let it air cool. So far NO reported failures in over 50 years and locks in use all over the world.
These other methods may work but to me they are more work than they are worth.

Bob Roller