Spring information

[David Rase]

I am replacing a spring on a wheel lock and have a question about tempering.  I have made several flat springs in the past using 1085 with excellent results.  What concerns me with this wheel lock spring is the thickness.  Final leaf thickness will be .160".  The springs I have made in the past were never this thick, all of them less than .100".  I want to make sure I temper the spring correctly as I have about 8 hours of machining and filing time in this spring and really don't want to hear that dreaded ping when a spring breaks.  The material is 1080.
Thanks, David   

[45-110]

i hate to offer my technique(s) as i don't want to be responsible for a fracture. but i think 1080 gives a little more margin in heat treating than say 1095. i know about a bunch of hours in fabricating a beautiful spring and then comes the black art of tempering, stressful! show us a picture of the spring.
best
kw

[smart dog]

Hi Dave,
I hardened and tempered 2 mainsprings for wheelocks.  One was from 1075 steel and the other cast from 5160(?).  For both I tempered at my usual 750 degrees for 1 hour.  Because of the mass of wheelock mainsprings, I think you could consider tempering as high as 800 degrees. Also Dave, I always normalize mainsprings before hardening them.  If I were in your shoes, I think I would try 800 degrees first and see how it goes.  If too weak, then I'd harden the spring again and temper to 750.   However, the end result has to be a very strong spring because they have to have strength sufficient to power the wheel even after powder fouling and even loose priming powder gets between the wheel and the lock plate. That is absolutely critical or you will wind the wheel after 10 shots, fire, and it does not budge.

dave

[Justin Urbantas]

If it were me, I would try to contact Bolek, and ask him. If anyone knows wheellocks, its him.

[jerrywh]

I agree with smart dog. I would temper that spring at 800° for an hour.  A normal spring would only take about 20 minutes but in tempering you should figure on 1/8" of thickness = 20 minutes at the tempering thickness. Since that spring is so thick I would give it an hour. 1080 is a fairly forgiving steel but not completely.  When I first made locks I used 1075. But if not tempered correctly they will break also.

[jerrywh]

Here is a tip Dave. Whenever you are making a spring the first thing to do is to heat the piece of steel to a good red heat and observe it to see if there are any flaws in it. If the steel has a flaw in it the flaw will show up as a white hot streak in it. You can see these flaws when the steel is red hot. A crack, no matter how small will show up as a white streak.  These cracks are possible even in new steel bought from a supplier. A heat treating engineer taught me this and it saved me many an hour of hard work. He also said the best spring steel is obtained from old cars because the suppliers give the best steel to the auto industry.

[James Wilson Everett]

Guys,

i have made a great number of springs using 1095.  Heat to 1450, quench in brine without stirring or swirling the part.  Temper at 810.  Please realize that the heat treating of steel will not effect the load/deflection property in any way - not at all.  Identical springs tempered at 650 or 750 or 850 will all have an identical load/deflection characteristic.  The only way to make a spring stronger or weaker is to change its physical shape, size, or thickness.

Here is a quote from people who know:

The Iron Age Volume 89 May 9, 1912, page 1151

The stiffness of a piece of steel cannot be increased by alloying nor by heat treatment.  By this I mean that provided the elastic limit is not exceeded, the amount of deflection for a given load cannot be decreased.  However, heat treatment will raise the elastic limit so that a much greater load can be carried without causing a permanent set.  Until the elastic limit is reached all steels, no matter how treated or of what nature, will deflect the same amount under the same load.  However, the poorer grade steel or the un-heattreated one will reach its elastic limit first and will then deflect much more and retain a permanent set.


Jim

[Bob Roller]

Hi Dave,
I hardened and tempered 2 mainsprings for wheelocks.  One was from 1075 steel and the other cast from 5160(?).  For both I tempered at my usual 750 degrees for 1 hour.  Because of the mass of wheelock mainsprings, I think you could consider tempering as high as 800 degrees. Also Dave, I always normalize mainsprings before hardening them.  If I were in your shoes, I think I would try 800 degrees first and see how it goes.  If too weak, then I'd harden the spring again and temper to 750.   However, the end result has to be a very strong spring because they have to have strength sufficient to power the wheel even after powder fouling and even loose priming powder gets between the wheel and the lock plate. That is absolutely critical or you will wind the wheel after 10 shots, fire, and it does not budge.

dave

Smart Dog,
It's 6150,the castable spring steel. I think most cast springs are made from it
but I am no expert on cast springs of any kind.What does a wheel lock mainspring
look like?
Bob Roller




Bob Roller

[jerrywh]

Springs can be cast from any spring steel. I have had them cast in 1095 and 01. I don't like 6150 because it doesn't get very hard when hardened.  It only has .5 carbon content. Not so good but it is very forgiving when beginners use it and don't draw it enough.

[jerrywh]

"
The Iron Age Volume 89 May 9, 1912, page 1151

The stiffness of a piece of steel cannot be increased by alloying nor by heat treatment.  By this I mean that provided the elastic limit is not exceeded, the amount of deflection for a given load cannot be decreased.  However, heat treatment will raise the elastic limit so that a much greater load can be carried without causing a permanent set.  Until the elastic limit is reached all steels, no matter how treated or of what nature, will deflect the same amount under the same load.  However, the poorer grade steel or the un-heattreated one will reach its elastic limit first and will then deflect much more and retain a permanent set."

The flaw in this statement is when it says ALL STEELS.  NOT SO.

[B.Barker]

Dave, Frank house posted on the CLA fb page about how he tempers mainsprings now. I think he draws the temp back twice but not sure. I'm sure you can do a search and find it.

[David Rase]

Hi Dave,
I hardened and tempered 2 mainsprings for wheelocks.  One was from 1075 steel and the other cast from 5160(?).  For both I tempered at my usual 750 degrees for 1 hour.  Because of the mass of wheelock mainsprings, I think you could consider tempering as high as 800 degrees. Also Dave, I always normalize mainsprings before hardening them.  If I were in your shoes, I think I would try 800 degrees first and see how it goes.  If too weak, then I'd harden the spring again and temper to 750.   However, the end result has to be a very strong spring because they have to have strength sufficient to power the wheel even after powder fouling and even loose priming powder gets between the wheel and the lock plate. That is absolutely critical or you will wind the wheel after 10 shots, fire, and it does not budge.

dave

Dave,
So I have my spring all filed out and polished.  I am assuming that the 1080 steel was normalized when I bought it since I was able to mill and file it in the as purchased state.  On previous springs I have made, I heated the material up with my oxy/acetylene torch using a neutral flame in order to bend it.  Once I had it arched to the shape I needed, I would heat it up red and quench it in oil to harden it.  I then polished the spring and then tempered it. 
You convinced me several years ago when I was upgrading my electric furnace from analog to PID controller to spend the extra money on a ramp soak controller, which I did.  My ramp soak can be programmed for up to 30 steps.  I want to heed your advise and normalize the spring before hardening.  That suggestion makes perfect sense as the spring has not been heated up evenly after heating and arching.  I would like to know if you would give me a suggested set of parameters for my PID for normalizing the spring.  I just replaced my heating element/insulation muffle in my furnace, after 20+ years of use the element broke, probably due to heating and cooling which made the element brittle, so I am ready to justify buying the ramp soak PID.
Thanks, Dave       

[David Rase]

Dave, Frank house posted on the CLA fb page about how he tempers mainsprings now. I think he draws the temp back twice but not sure. I'm sure you can do a search and find it.

Brian,
Funny you should mention double tempering.
I was just sent an email from a friend in Montana who told me about an article the read that stated,  "In tempering high speed steel tools, it is common practice to repeat the tempering operation or "double temper" the steel..... After the first tempering operation, some untampered martensite remains in the steel. This martensite is not only tempered by a second tempering operation but is relieved of internal stresses..."
David

[smart dog]

Hi David,
I would suggest normalizing at 1600 degrees for 5-6 minutes and let air cool slowly.  Probably best to just turn off the oven and let the spring cool inside with the oven.

dave

[David Rase]

Hi David,
I would suggest normalizing at 1600 degrees for 5-6 minutes and let air cool slowly.  Probably best to just turn off the oven and let the spring cool inside with the oven.

dave

Thanks

[D. Taylor Sapergia]

Here's a picture of the wheellock I made back in the last century.  As you can see the spring is made of pretty stout stuff.  I was lucky with the heat treat on this, simply making a sort of reflection kiln out of fire bricks and used two mapp gas torches for the heat source.  Very primitive, but the spring is still going 'strong'.

[jerrywh]

 Double tempering is a good idea if you don't have a furnace but it is not necessary if you do and you hold the temp for the proper amount of time. When I temper springs with a torch I usually double temper because it is hard to hold the temp, for 20 minutes. Normalizing is good before you harden. Those wheel locks are awesome Got to go the Seahawks are kicking off..
 

[Daryl]

better parts picture of Taylor's wheel lock.

[Bob Roller]

It's easy to see why only wealthy folks could have one of these locks AND
the gun.I wonder how they did it without pyrometers and spring material
that may or may NOT be spring material?
I remember reading an article by Lucian Cary many years ago about an
old man in Kentucky,I think his name was Wyatt Atkinson who made
his springs by forging a cold chisel out to whatever was needed.Where there's
a will there IS a way.
Once in a rare while I will do a "redrawn"spring by drawing it again after
polishing to a bright finish.I play the flame over the spring until I get the
deep purple or indigo I want and then quit.It makes the spring even better
looking and does not seem to harm the reliability a bit.

Bob Roller

[jerrywh]

Bob I use to wonder the same thing. How they did it without a pyrometer or a furnace. Once I was working on an original English lock and was studying the tool marks and such for clues. On two different locks I noticed  that there was some lead in between the leaves of the main springs. That was the clue that led me to the lead bath tempering method. Lead melts at about 625F. So for a long time I used that method. I use to set the lead pot right in the forge.  I also noticed that on some broken springs there was visable layers of the steel. I think some gunsmiths made their own cruciple steel for springs.

[Gunnermike]

I made a wheellock last year and tempered it with an acetylene torch and dunked it in vegetable oil and this happened -



I was posting the build on another muzzle loading site and a moderator recommended 10-20 minutes in a 700-750F lead pot for the new mainspring, so I did 15 minutes at 720F -



That seemed to work okay:





I still need to re-harden the parts, the small parts got hard, but the larger parts not so much!
Mike

[Rolf]

Impressiv wheelock, Gunnermike! Thats alot of work. Is it for a rifle?

Best regards
Rolf

[Jim Kibler]

Guys,

i have made a great number of springs using 1095.  Heat to 1450, quench in brine without stirring or swirling the part.  Temper at 810.  Please realize that the heat treating of steel will not effect the load/deflection property in any way - not at all.  Identical springs tempered at 650 or 750 or 850 will all have an identical load/deflection characteristic.  The only way to make a spring stronger or weaker is to change its physical shape, size, or thickness.

Here is a quote from people who know:

The Iron Age Volume 89 May 9, 1912, page 1151

The stiffness of a piece of steel cannot be increased by alloying nor by heat treatment.  By this I mean that provided the elastic limit is not exceeded, the amount of deflection for a given load cannot be decreased.  However, heat treatment will raise the elastic limit so that a much greater load can be carried without causing a permanent set.  Until the elastic limit is reached all steels, no matter how treated or of what nature, will deflect the same amount under the same load.  However, the poorer grade steel or the un-heattreated one will reach its elastic limit first and will then deflect much more and retain a permanent set.


Jim

James,

Thanks for the exerpt from the Iron Age book.  This is a very true statement that everybody interested in springs should understand.  It's something that I've mentioned many times in the past.  Believe it....  This is coming from a former metallurgist.  Only one more thing to add.   Temper at the highest temperature such that your spring still returns to the previous un-stressed dimensions.  That is, it doesn't develop a "set".  This will make it less susceptible to defects, stress risers etc.  This temperature WILL vary with steel grade or alloy.

Jim

[smart dog]

Hi,
Let me clarify something.  When I mentioned heating to 800 and see if the spring is too weak, I was referring to a temper that might be too high to prevent set from occurring resulting in a weak action.   

dave

[jerrywh]

This comment is not intended for anybody. Just a general tip. When you read something in a book or hear information given orally try it out for yourself on some unimportant piece for your self.  I have read tons of false info in books.