Can a mainspring be made stronger?

[M. De Land]

Sorry, but you have no idea of what you are talking about. Common high carbon steels make the best springs at Rc hardness between 42 and 46. And a good file is 65 to 67 Rc. 62 Rc would not last long as a file. Mass has nothing to do with temper heat, only time in soak, and longer times make no change once the atomic shift has completed, it is locked unless a higher temperature is then applied. If a piece of steel was tempered to 55Rc, at 500° temp, then cooled and reheated to 500°, it could soak all day and never get softer or have any change in Rc.

If you say so but I think I'll stick to what my old gunsmith books say as it seems to be working for some time now.
And mass does have an effect on time in soak or the alloy would not be rated by its thickness. As I said previously it does no harm to stay in the oven or lead longer but it is not necessary. Difference of opinion I guess.

 

[LRB]

You misread. I said that mass has effect on time, but mass has nothing to do with the heat of the temper. Once a piece is given time for the chosen temp to become even throughout, and time for the atomic shift to be complete throughout, it's done. However if for some reason the soak ran over time, or a person re-tempered at the same heat a dozen times, the hardness will not be altered. A second temper is insurance that everything internal went as desired. At worst, it does no harm.

 

[M. De Land]

You misread. I said that mass has effect on time, but mass has nothing to do with the heat of the temper. Once a piece is given time for the chosen temp to become even throughout, and time for the atomic shift to be complete throughout, it's done. However if for some reason the soak ran over time, or a person re-tempered at the same heat a dozen times, the hardness will not be altered. A second temper is insurance that everything internal went as desired. At worst, it does no harm.

Actually it sounds like we are in pretty much agreement. On the file front I was simply quoting what I have read that any thing over 62 Rc was considered in the file hard realm. Always open to new information but at this point in my ever evolving knowledge improvement, blue color tempering at 600 F. seems to work quite well.

 

[ThumperJones]

Alright so I got the "new and improved" forged mainspring in. It's noticeably beefier all around. The folks at L&R included a nice template to show where to drill a new hole, and slot the lock plate for the little hook at the top of the spring. All that went rather uneventfully thank goodness. I slapped her back together and the lock is very much noticeably quicker. Cocking effort isn't substantially higher, but the "output" is much better if that makes sense. Should be a very welcome change all around!

The new spring is a lot wider and chunkier so I had to do a little inletting to get it to fit.

My vast selection of chisels and tools consists of as follows:
1- ratty old 1/4" whoknowswhatkind chisel with a busted tip.

That's it.

No pics of the inlet work, but it went fairly smooth considering I basically had to remake a chisel and had zero experience or idea what I was doing. I took the opportunity while the lock was out to strip off some off the nasty red muddy oil off the stock and refinish it with Tried and True Oil Varnish. Looks amazingly better already.

Anyways, after having the new spring and removing wood to get it to fit, I reckon it's gonna stay in there. Thanks so much for all the help and info.

**If anybody is curious, the template i received stated that the change to the forged springs ocurred in 2012.**




View attachment 17000

 

[ThumperJones]

*The shiny spring is the new forged one. The dull spring is the original cast spring.

 

[45man]

Lead does not melt at 600°.

It sure does and when I smelt new lead I keep it at 600 to remove any junk that floats, like zinc. I was given 200# of cable sheathing to find some ingots had zinc most likely from the soldered joints and skimming at 600 without fluxing will remove most.
For harder alloys I add tin and antimony with a special flux and it melts in at 600. I use a good thermometer.
Casting is different and I cast pure at about 800. Lead with tin and antimony will get liquid at a lower temp then 600 too.

 

[45man]

Now THAT is a spring! Good for a few centuries. Put a dab of grease on the tumbler contact.

 

[LRB]

Sorry, but no. Pure lead does not melt at 600°. 621°to 625°. Alloys may change that, but pure lead does not. If that is what your thermometer reads, it is wrong.

 

[M. De Land]

Sorry, but no. Pure lead does not melt at 600°. 621°to 625°. Alloys may change that, but pure lead does not. If that is what your thermometer reads, it is wrong.

Just looked up the typical hardness on Engineers Edge web site for 1095. The Rc is typically 48-51 with a maximum of 59. Looks like the 600-700 degree draw is right in with what they say is middle of the road but your hardness factors seem to be a bit low. Wondering what kind of a spring uses an Rc of 59? Perhaps that means it's as hard as it can be made into a practical spring. 600 produces an Rc of 55 which is probably why it resists set so well.

 

[LRB]

I go by spring making recommendations from Jim Kibler, metallurgical engineer, lock maker, long rifle builder, and other metallurgical info from Kevin Cashen, metallurgist, international metallurgy consultant to industry , and a world class sword and knife maker. Information and advice from these and a few other metallurgists greatly helped me to be successful in my knifemaking and how to separate the chaff from the wheat as far as heat treating steel.

 

[M. De Land]

I go by spring making recommendations from Jim Kibler, metallurgical engineer, lock maker, long rifle builder, and other metallurgical info from Kevin Cashen, metallurgist, international metallurgy consultant to industry , and a world class sword and knife maker. Information and advice from these and a few other metallurgists greatly helped me to be successful in my knifemaking and how to separate the chaff from the wheat as far as heat treating steel.

I have to ask, have you ever actually made any gun lock springs of 1095, tempered them at 600-700 and tested how they perform or are you transposing knife blade numbers to springs and calling it good?

 

[LRB]

I have made springs. I have modified and re-heat treated springs. Flat and V. I did light gun repair, custom modification, Restocking, bedding, general work that did not require lathe, or mill work since '74. Also a good amount of action jobs. I temper springs at 750°. Years ago I used a lead bath and some guess work, but now an Evenheat Rampmaster 2 oven. How and what do you mean transpose Knife blade numbers? What numbers? Any numbers regarding one would be the same for the other, using the same steel.

 

[M. De Land]

I have made springs. I have modified and re-heat treated springs. Flat and V. I did light gun repair, custom modification, Restocking, bedding, general work that did not require lathe, or mill work since '74. Also a good amount of action jobs. I temper springs at 750°. Years ago I used a lead bath and some guess work, but now an Evenheat Rampmaster 2 oven. How and what do you mean transpose Knife blade numbers? What numbers? Any numbers regarding one would be the same for the other, using the same steel.

Good reply, it helps me have more confidence in what you say ! I have the same oven and love it! No experience in knife blade heat treating but quite a bit in flat, V, coil and combination springs, case hardening and cutting tool (reamer and cherry) fabrication.

 

[LRB]

Never made a coil spring. Always just bought those. I know you are a good gunsmith, maker and machinist. I sometimes follow your work on Shiloh. I envy the guys that have that kind of equipment and know how to use it. I had a close friend nearby that would do anything in machining that I needed, but he died in the early nineties. Helluva gunsmith and shooter, but could not inlet well or do triggers, so we traded off work here and there.

 

[45man]

Sorry, but no. Pure lead does not melt at 600°. 621°to 625°. Alloys may change that, but pure lead does not. If that is what your thermometer reads, it is wrong.

Pure will melt at 620 as I have melted tons at 600. I can give you a 20 degree difference. A piddle of course. Maybe my thermometer is a little off but when it says 600 I can melt in antimony with a 1166 degree melting temp.
I still think over 700 is too soft to temper a spring. It will take a set and lose power.

 

[Zonie]

One of the books I have which shows the tempering temperatures for carbon steels along with the color and use says:

430°F = yellow = scrapers, lathe cutting tools, hammers
470°F = straw = punches, dies, hacksaw blades, drills, taps, knives, reamers
500°F = brown = axes, wood chisels, drifts
540°F = purple = cold chisels, center punches, rivet sets
570°F = blue = screwdrivers, springs, gears, picks

I'm sure many of you had the fun of tearing apart a old spring powered clock? If you remember, the coil springs were almost always a beautiful, rich blue color. The tempering temperature was responsible for that.

That said, just because your chisel or screwdriver doesn't show a brown or blue color doesn't mean it wasn't tempered to the colors I show above. The color is a very thin layer of oxide and it is usually removed by later operations in the manufacturing of the tool.

 

[M. De Land]

I love these discussions that reveal different views on a subject as there is always something more to learn and try out. I pick up some of the neatest stuff in these discussions of our common interests ,often times slapping myself in the fore head (figuratively speaking) and saying to self, "why didn't you think of that"! Kind of like finding a gold nugget in a stream bed while your out hunting or fishing.

 

[LRB]

Clock springs used to be 1095 steel, and yes, it was heat tempered blue. Any of you, go make yourself a 1095 mainspring for a gun lock, or just a V facsimile of a gun lock spring. Harden then temper at 570°F, test it, and see how long that will last. Clock springs work with very different stress directions than do V springs of the size for gun use. A good lock main spring will be gray neutral in color if HTed in an oven. Ask world class gun maker Jerry Huddleston. He tempers springs at 725°, which I find a tad low, but obviously it works. Ask Jim Kibler. He is a professional metallurgist as well as one of the finest rifle makers in the country. He tempers at 750°. If he has time, he will talk to you.

Everyone has the privilege of settling on their own level of ignorance. No one has the right to impose it on others

 

[Zonie]

You are right about the stress concentrations being different between a spiral clock spring and a V spring and the V spring often used for the mainspring in a lock has a much higher amount of stress when it flexes.

I was just trying to show that a temper of 570°F is used for making some springs.

The higher 725° to 750°F temper will soften the steel more which makes it better suited to the stress concentration often found in lock mainsprings. In other words, if these higher tempering temperatures are used, the spring will be much less likely to break.
This comes with the risk of the spring being slightly bent or deformed when it is first used and taking a "set" which provides slightly less power.
Once this slight bending has occurred, it won't continue to bend further so its ability to power the **** or hammer will remain constant.

I think this explains why mainsprings that are tempered in the 650°-700°F range work without breaking and will maintain their strength.

 

[M. De Land]

Clock springs used to be 1095 steel, and yes, it was heat tempered blue. Any of you, go make yourself a 1095 mainspring for a gun lock, or just a V facsimile of a gun lock spring. Harden then temper at 570°F, test it, and see how long that will last. Clock springs work with very different stress directions than do V springs of the size for gun use. A good lock main spring will be gray neutral in color if HTed in an oven. Ask world class gun maker Jerry Huddleston. He tempers springs at 725°, which I find a tad low, but obviously it works. Ask Jim Kibler. He is a professional metallurgist as well as one of the finest rifle makers in the country. He tempers at 750°. If he has time, he will talk to you.

Everyone has the privilege of settling on their own level of ignorance. No one has the right to impose it on others

Sounds good to me Wick! I'll be testing some of the differing temper draws and see what I find! May be time for an update to my thinking,,,,,,,,,, It's happened before!