oil quench and tempering

[JohnN]

Tried this the other day on a frizzen spring and just want to make sure I did it right. Heated the spring to non magnetic then quenched in 30 weight oil. Put the spring in a small container and covered in oil. Started the oil on fire and let it burn down. Was burning the oil down good enough or should I have kept the heat from the torch on it ? Seems like you would empty the tank with the time it took the oil to burn down. Thanks.

[D. Taylor Sapergia]

By tempering the frizzen in burning oil, you have effectively created a spring, not a frizzen.  The frizzen needs to be tempered at only about 375 - 400 degrees such as can be done in a toaster oven for an hour.  Your burnng oil will have imparted a dark blue hue to the frizzen, whereas the toaster oven will have left a dark straw colour.  Now your frizzen is too soft, and will need to be repolished, rehardened, and tempered properly.

[rich pierce]

Umm, Taylor, it is a spring he’s hardening and tempering.

[Bob Roller]

By tempering the frizzen in burning oil, you have effectively created a spring, not a frizzen.  The frizzen needs to be tempered at only about 375 - 400 degrees such as can be done in a toaster oven for an hour.  Your burnng oil will have imparted a dark blue hue to the frizzen, whereas the toaster oven will have left a dark straw colour.  Now your frizzen is too soft, and will need to be repolished, rehardened, and tempered properly.

Taylor is right about the frizzen. The burning oil is a method with a high failure rate for me.Open flame
and smoke are not wanted in my shop.Melted lead takes too long.
I gave upon it over 50 years ago and temper the springs in my locks using another antiquated method
which is after the hardened spring or frizzen or tumbler,fly and sear are polished after being removed from
the quench agent which is now 5W30 motor oil. I use a Bernz- O- Matic torch with a special tip to localize the
point of the flame directly on the part to be tempered. On springs the color I use are dark blue with a dwell
time at the bend in the mainspring.Sear and frizzen springs are a bit tricky and I watch the color closely on
these with little dwell at the bend of a sear spring and only slightly more on the frizzen spring.
Frizzens,flys,sears are tempered at a straw color. Springs are 1075 and the other three components are
oil hardening 0-1. There is nothing exotic about this either in material or methods as far as I know.
I have been told by "experts" that my methods won't work but over 50 years of success with locks all over the
world still in use for decades say THEY are wrong.These are skills learned by DOING and practice,practice and
more practice.Nothing succeeds like success and nothing is more obvious than failure and quitting.

Bob Roller

[JohnN]

Talking about a frizzen Spring not a frizzen.

[D. Taylor Sapergia]

How the heck did I miss that!!?  Sorry for my confusion. 

Yes, you can temper your frizzen SPRING by heating oil to the point of ignition, and then letting the oil burn right off.  I have done it a couple of times, but in the back yard, not in the shop.  I just used motor oil, set it afire and let it burn out.  My spring was excellent following this treatment.  It took some time to get the oil hot enough to ignite, using a propane torch played right on the oil.  Drop the spring into the burning oil, and leave it there until all the oil is consumed.

[G_T]

I guess the burning oil is not hot enough to thermal shock the glass hard spring and cause micro cracks?

[Craig Wilcox]

Nope- the oil that is not yet burning takes some time to heat up, therefore no thermal shock.  About like putting it in the oven, then turning the oven on and let it warm to the set temp.  Small amounts of oil, absent forced air, really burn at quite low temps.  Gasoline, if you fill a little can and light it, does not get very hot either.  Yellow, smoky flame for both products burning at atmospheric temps and pressures.

We used to take a no. 10 can, fill it 3/4 full of sand, dump a pint or so of gasoline into it, and then drop a match.  It will warm up your hands or feet, with no danger of explosion.  If it weren't for the nasties in it, you could cook your dinner.

[Scota4570]

Lead bath and thermometer from one's bullet casting  kit works pretty darn good.  The temperature of the oil burning varies by the type of oil.  I would not risk my time to make the spring on such sketchy drawing methods. 

[JohnN]

I followed the directions in Kit Ravenshears booklet about springs. Just enough 30 weight oil to cover the spring and defiantly outside.

[David R. Pennington]

I have had varied success with the burning oil method, but mostly they ended up too soft so you get a second chance. (Too hard and you start over.) I have had more consistent results with color tempering. Sometimes on small parts I put the polished part in a little sand in a small iron skillet on forge fire and turn the part in the sand to get more even heat as I watch for colors, bringing heat up slowly. Try your spring, you may have a good one. If it lays down do it again.
I made a frizzen spring a few years ago for a fellow in our club with an old lock that parts weren’t available for, tempered in the oil can and he’s still shooting it.

[LRB]

When tempering steels for a spring by color, first polish/fine sand to bright metal. Then degrease and do not touch with bare fingers. Slowly heat through the color phases and stop when it goes to gray/neutral, then air cool. Blue color may be OK for 1075, but it is not enough for higher carbon steels. Natural finger oils will affect the color transformations. Keep it clean. Do this in good light. If you have a good trust worthy lead thermometer, a lead bath for 10 minutes or so at 750° will make a superior spring. Tempering by color is a poor way to go, but may be the only way available for many.

[Bob Roller]

When tempering steels for a spring by color, first polish/fine sand to bright metal. Then degrease and do not touch with bare fingers. Slowly heat through the color phases and stop when it goes to gray/neutral, then air cool. Blue color may be OK for 1075, but it is not enough for higher carbon steels. Natural finger oils will affect the color transformations. Keep it clean. Do this in good light. If you have a good trust worthy lead thermometer, a lead bath for 10 minutes or so at 750° will make a superior spring. Tempering by color is a poor way to go, but may be the only way available for many.

Maybe I have a really good eye for color but over 5 decades of success world wide says it works.

Bob Roller

[Dan Fruth]

I recently did springs, and the lead pot method of tempering worked perfect. I used a long stem thermometer to monitor the lead temp

[LRB]

Not really Bob. That just says it works for YOU, and maybe 1075.

[Bob Roller]

Not really Bob. That just says it works for YOU, and maybe 1075.

Seeing as how it does work for me I will stay with it and that IS reality.

Bob Roller

[Scota4570]

https://www.amazon.com/Lyman-2867793-Casting-Thermometer/dp/B001TQ8Y6Q?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-d-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B001TQ8Y6Q

How many broken springs is worth 38 bucks ?

[jerrywh]

 I  agree with Scota4570. The best method is a furnace, The next best is the lead method, then the color method. Then the burning oil.
  I could wright a long paragraph on that burning oil method but it would just be boring to most of you.
 The color method works OK if you have a lot of experience.
 Tempering a spring is a lot like cooking a cake. The spring has to get done on the inside as well as the outside. There is a time factor to the process. The rule is 12 minutes for every 1/8" of thickness. Therefore a main spring that is .100 thick should be held at the tempering temp for about 10 minutes.
 About 75% of the time people get just plain lucky. I use to make springs by the dozen and had to get a heat treating engineers advise at one point about 55 years ago. The time factor was my problem.
 Oil never gets hot enough to temper a spring but the flame is about 1500° go figure. The flame heats the spring and the oil cools it.  Between the two it works most of the time. Most of the time isn't good enough for me.

[JohnN]

Would most of you agree that a frizzen spring doesn’t need as much attention as a main spring ?

[rich pierce]

Would most of you agree that a frizzen spring doesn’t need as much attention as a main spring ?

One would think so until their frizzen spring breaks. I had a production one snap overnight in a spring vise and it wasn’t overly compressed either. Another time I made a replacement for style purposes from junkyard steel and when I compressed it it said ”tink!” The few springs made since then have been 1070 or thereabouts and I burned off motor oil to temper them. It has worked and it’s kinda fun. 

[LRB]

Not really Bob. That just says it works for YOU, and maybe 1075.

Seeing as how it does work for me I will stay with it and that IS reality.

Bob Roller

No one asked you to change or even suggested you change, did they?

[Bob Roller]

Not really Bob. That just says it works for YOU, and maybe 1075.

Seeing as how it does work for me I will stay with it and that IS reality.

Bob Roller

No one asked you to change or even suggested you change, did they?

Believe it or not but I have had people to ask me to change my spring making methods
but I ignored them**.Lock making IS a labor intensive job and at this point in time I am
comfortable with what I do which is less and less.I haven't done anything serious in the'shop for about 6 weeks
and just today started a couple of small Mantons on the L&R externals for a local man.
**One man wanted a thicker spring,another told me of some weird method his grandpa used that I
prompltly forgot.This was years ago and I am set in my ways and too old to care one way or the other.
There were others but they are mostly long forgotten.One request I do remember was to forge springs from cold chisels
like some geezer in Kentucky was doing. I remember telling him that figuring out the hardest possible way to do
anything was not on the schedule.

Bob Roller

[jerrywh]

 Old guys like Bob roller and I have methods that worked for many years. I confess that I often use the same method as bob a lot of times , mostly on frizzen springs and sear springs.They don't flex as much as a main spring does so they are more forgiving.  I don't like  to recommend it for beginners though. 

[bob in the woods]

I used to use the oil method, but have gone to the lead bath and am much happier with the overall results. That said, I've had a couple of instances of attempting to "fix' springs on imports and they remained mushy no matter what I did. Knowing what material you're working with is key.

[Bob Roller]

From the late Lynton McKenzie came this.Take the broken mainspring,heat it,forge it flat and make a
screw driver or other small tool from it..

Bob Roller