Springs, Spring Making, and Spring Materials

[Rasch Chronicles]

Hello everyone,

The Wheelock thread has really caught my attention, and even though I can't see any of the pictures, it is very interesting to read. The spring discussion also caught my interest and led to me discussing it with members. I also went rummaging through the internet's bowels, digging up information. Undoubtedly, many of you know much more stuff, so feel free to add to the conversation and general learning.

I found out that spring material comes in several flavors. You will also note that 1095 is one of the recommended materials, and for many applications where one expects longevity and repeatability, it is the choice. But the heat treating and tempering are much more fastidious and finicky than other steels.

Several references peg the 1060-1075 as the easiest to work with. Tempering is stated as 700F° for two (2) hour which yields an Rc of 47. Remove from tempering medium or oven and allow to air cool in still air.

I think we can infer that reaching Rc 47 is the key to a proper temper. So a 1095 spring will have to be tempered at 750 F° in order to be Rc47 and function properly.

I know from years of reading that the finish on the spring can also determine how well it cycles. It occured to me that you could bead blast the spring as much as possible, then anneal it again, harden, and temper. The bead blasting would nullify any surface defects (scratches, nicks, small micro cracks) and re-annealing it would soften the now work hardened surface before retempering. Barring bead blasting, I would finish it with different grades of sand paper, until I had a uniform surface on all sides and then polish.

I am willing to bet that the compression side of the bend is what causes springs to snap. That metal has to go somewhere, probably squeezing out on the inside of then bend. First thing I would do is bend it around a small drill rod, so it wouldn't fold as bad. Then I would sand it flat on both edges. Then I would go at relieving all edges and sanding it on every surface.

You probably know more than I do about this and there might be something I am missing here.

Here are the predominant spring steels:
 
1050: for the purpose of greatest uniformity with Rockwell held to the medium or low side of range. It can be easily formed, blanked, shaped or slightly drawn, heat treated, hardened and tempered. Used for flat springs, coiled springs, spring latches, prong lock washers, etc.

1075: an excellent choice for an all-purpose Spring Steel Strip. It is of fine grain structure, has been completely spheroidized with Rockwell held to the medium or low side of range. Can be easily formed and heat treated - stocked in an unusually wide thickness range'

1095: is the very finest of commercial quality High Carbon Spring Steel Strip available.  It is of fine grain structure, has been completely spheroidized with Rockwell held to the medium or low side of range. Can be easily formed, blanked or shaped, heat treated, hardened and tempered. Intended for springs or other applications such as mechanical springs, etc.

Blue Steel (Clockspring material 1095): This is perhaps the most universally used of all tempered spring steels. Recommended for various types of coiled and flat mechanical springs such as ignition vibrator springs, springs for timing devices, springs for the electrical and electronic field, steel tapes, rules, etc.

5160: Medium high carbon - chrome/manganese/silicon alloy steel with a 0.60 C content. Considered an exceptional spring steel. Used for flat springs, coiled springs, spring latches, etc. Forge between 2100 and 2200 F. 5160 is normally hardened in oil. Recommended quenching temperature is 1525 F, with a wide range of tempering between 800 and 1300 F.

W1 Tool Steel: Essentially 1095 w/manganese and silicon. W1 is a plain carbon steel and machines with ease. Forge at 1900 F down to 1550 F. Do not forge below 1500 F. Heat treatment is somewhat dependent upon section size, or intricacy of the part. For large sections, or intricate shapes, slowly preheat to 1100 F and then slowly increase temperature to 1500 F. Hold for 10 to 30 minutes and then quench in water or brine. Caution, does undergo considerable distortion during quenching. Temper at 350 to 650 F for Rockwell C of 64 to 50.



Formed Springs Requiring Heat Treatment
1050
Normal Temp 1550° - 1650° F
Anneal Temp 1400° - 1500° F
Hard Temp 1500° - 1550° F.
Oil Quench Rc58

Rockwell Drawing Temp.
1050
400F°   600F°   700F°   800F°   900F°   1000F°   1100F°   1200F°
Rc52    Rc45     Rc39     Rc35    Rc31     Rc27       Rc22      Rc n/a


1075
Normal Temp 1550° - 1650° F
Anneal Temp 1400° - 1500° F
Hard Temp 1475° - 1550° F.
Oil Quench Rc64


Rockwell Drawing Temp.
1075
400F°   600F°   700F°   800F°   900F°   1000F°   1100F°   1200F°
Rc59     Rc53     Rc47     Rc44     Rc40     Rc36       Rc32       Rc26
 

1095
Normal Temp 1550° - 1650° F
Anneal Temp 1400° - 1500° F
Hard Temp 1440° - 1475° F.
Oil Quench Rc 66

Rockwell Drawing Temp.
1095
400F°   600F°   700F°   800F°   900F°   1000F°   1100F°   1200F°
Rc62     Rc55     Rc49     Rc45     Rc41     Rc38       Rc34        Rc30

There are probably other suppliers, but these are the ones I found that sell in small quantities.

Suppliers:

Blue Spring Steel 1095: up to .187 thickness
http://www.mcmaster.com/#blue-spring-steel/=dngvy8
http://www.brownells.com/.aspx/pid=390/Product/EXTRA_WIDE_SPRING_STEEL

1050 Carbon Steel: up to .187 thickness
http://www.admiralsteel.com/products/200/cra1050.html

1075 Carbon Steel: up to 3/16 thickness:
http://www.mcmaster.com/#grade-1074/1075-steel/=dnh1dy

5160 alloy steel - 1060 w/ chromium/manganese/silicon added: ¼ inch to 3/8th thickness
http://www.mcmaster.com/#grade-5160-steel/=dnh40b

O1 alloy steel – 1090 w/ manganese and chromium: 1/64th through 3/8th, and metric 3mm to 6mm
http://www.mcmaster.com/#grade-o1-steel/=dnh7xh

W1 Tool Steel – 1095 low alloy steel 1/16th through 3/8th
http://www.mcmaster.com/#grade-w1-tool-steel/=dnqw32


As always, I hope this is helpful to other folks on the forum!

And I promise I will get around to fiinishing the Findings post...

Best regards,
Albert “Afghanus” Rasch
Charged! Hog Hunting at its Best!
ΜOΛΩΝ ΛΑΒΕ!

[mattdog]

This is some useful information, particularly the charts.

Let's discuss some of your perceptions of this information:

First, bead blasting doesn't do much for removing surface imperfections.  It won't remove micro cracks, scratches or blemishes in the material.  It is great for removing the scale from cast parts and will take the color off from parts that have been previously heated so you can polish and see the colors on subsequent heating and quenching.  It will remove paint, better or worse depending on the grit of the medium.  Only filing, grinding and sanding will remove scratches and other imperfections on the surface.

Most spring failures (not all of course) are the result of improper heating/tempering/quenching process and/or imperfections in the material.  When a spring lets go in my experience it breaks on the outside of the bend, not the inside.  The material must stretch on the outside of the bend.  Try bending a wooden match beyond it's ability to stretch and observe where and how it breaks.  Same thing but different  I don't test for Rockwell hardness on my springs.  That's for the eggheads at the mill to figure out.  Spring design has an impact on how well a spring cycles but let's save that for another thread.

Thanks for the time and trouble it took to find the info. and post it.  

[alyce-james]

Albert; Thanks for your time you spent in your most recent post. Very informative information.  AJ

[LRB]

  One other cause of failure, which would be tied in with improper heat, is bend forming the spring at less than a red heat where it is to be bent. I believe Jim Kibler recommends a RC hardness of in the low 40's, as well as the late John Bivins.  You will also find that almost all heat treat charts will give slightly different results from one to another. Most often they will be close to one another, but will often differ in the exact numbers. With 1095, the charts are often printed with figures gathered from a water quench, on steel as thick as an inch. Thin sections of 1095 do not go well with a water, or brine quench. It will often break, or crack. a water/brine quench puts 1095 at the max hard it will achieve, whereas an oil quench will be one or two Rc points lower, or more, depending on the type of oil used. The remaining hardness from the temper heats afterwards, will be relative to the steels hardness after the quench.

[Glenn]

Albert thanks for all your assistance; very thorough as usual.  Yes, this was desperately needed by some of us at least.  Now we know what to look for, buy, and how to treat it.   

[Rasch Chronicles]

Howdy all!

Glenn, always happy to help! When I don't know something, I look it up and then share it. Lots of folks probably don't know this stuff either, and I have the time and inclination to put it together. I have some more notes to add to it that I found while reading further.

Many of the references mention tempering the spring by setting fire to used motor oil. That burns at 700 deg. Using 1070 as the median point, I infered that 1095 would have to cook at 750 to yield the same Rc. The real problem is how do you do that without a good kiln to work with? Iron plate with bottom heat and good eyes I guess!

Maddog I disagree (politely) with your shot blasting assertion. At one time, I made high speed low drag parts for some obscure military contraption at a plant I worked at. I would hand finish certain parts, then take them to a blasting cabinet where they were mercilessly pummeled until the piece looked like it was supposed to. The metal was a special Chromium/Cobalt alloy. Anyway I was told that the reason for the bead blasting was to make sure all micro fissures, micro cracks, and scratches were peened away. At a speed shop I helped out in we did the same thing to connecting rods after grinding and weighing them. The reason being was to peen any potential stress points from the metal. None of that stuff was spring steel though so... Oh, and that makes good sense on the outside curve being stretched and stressed. Would make a lot of sense to re anneal and normalize after forming, grinding, and finishing the spring.

I once ordered the DGW catalog when I was a boy. I wish I still had it! Anyway there was an article on spring making, and they used files. I do remember reading in several places over the years that springs should be quenched in light oils like olive, peanut, clean light weight motor oils, etc.

I'll add the notes when I have a little more time later this morning.

Best regards,
Albert “Afghanus” Rasch
PeTA: Why I Dislike Them So Much
ΜOΛΩΝ ΛΑΒΕ!

[Glenn]

Many of the references mention tempering the spring by setting fire to used motor oil. That burns at 700 deg. Using 1070 as the median point, I infered that 1095 would have to cook at 750 to yield the same Rc. The real problem is how do you do that without a good kiln to work with? Iron plate with bottom heat and good eyes I guess!

Albert “Afghanus” Rasch
PeTA: Why I Dislike Them So Much
ΜOΛΩΝ ΛΑΒΕ!

One idea I came up with is try to find an old gas oven used in pizzarias.  I'm sure you can crank them up pretty high and they are large enough to place long barrels in, etc.

I dont know how much one would cost but if you fond some place going out of business and/or replacing one it might be worthwhile to ask.

Might be a huge bump in the gas bill though

Just an idea anyway ...

[ironwolf]

  A charcoal pak would be the way to not oxidise it.

  KW

[bgf]

In my limited experience, leaving the spring too hard is far worse than a little on the soft side in most applications.  Could the burning oil temper still be used on steels that might normally require a higher temperature by using a hotter quench for hardening?  With my limited knowledge, I'm guessing that a higher quench temperature will decrease the hardness, so that a lower tempering heat is required.  Just curious, and probably all wrong.

[Dphariss]

In my limited experience, leaving the spring too hard is far worse than a little on the soft side in most applications.  Could the burning oil temper still be used on steels that might normally require a higher temperature by using a hotter quench for hardening?  With my limited knowledge, I'm guessing that a higher quench temperature will decrease the hardness, so that a lower tempering heat is required.  Just curious, and probably all wrong.

The burning oil temper is interesting.
I have read that the temp at the BASE of the flame is too low to make a spring.
I use a molten saltpeter bath.
Its a lot cleaner process.
Some use Spern Whale Oil for the burn method. Or so I am told.


Dan

[camerl2009]

 you can make springs by forging them from old leaf springs(5160) and car coil spings(also 5160) just got to draw it out to the right thickness and shape it

im in the process of making a new sping for a 150+ year old boot pistol i just got and old leaf spring is doing the job

[ironwolf]

  True, 5160 is more user friendly than any of the 10.. series steels.
 
  KW

[bgf]

In my limited experience, leaving the spring too hard is far worse than a little on the soft side in most applications.  Could the burning oil temper still be used on steels that might normally require a higher temperature by using a hotter quench for hardening?  With my limited knowledge, I'm guessing that a higher quench temperature will decrease the hardness, so that a lower tempering heat is required.  Just curious, and probably all wrong.

The burning oil temper is interesting.
I have read that the temp at the BASE of the flame is too low to make a spring.
I use a molten saltpeter bath.
Its a lot cleaner process.
Some use Spern Whale Oil for the burn method. Or so I am told.


Dan

Soybean oil seems to work well, also, and has less noxious fumes than motor oil.  Unless you get clean, non-detergent oil, there is a lot of "stuff" in detergent or used oil that it might be better not to burn in the workshop:).  I think the base of the flame is probably too cool, but the part gets heated to the proper temperature as the oil burns down and the heat spreads through the piece pretty quickly.  Bet it is only good for small relatively thin pieces, though.  I've only done patchbox type/size springs, not a mainspring sized one.  The saltpeter bath would probably be better for the bigger stuff.

[camerl2009]

  True, 5160 is more user friendly than any of the 10.. series steels.
 
  KW

its ok i used it in some knives 1095 is hard to get in scarp form

[doug]

     I make 5 or 10 main springs per year and have made at least 50 and probably more total.  I forge & then grind and file them out of drill rod almost exclusively and I assume that to be 1095.   The very first few I drew the temper to just past dark blue (grey) in molten lead.  For at least the past 10 years I used the burning oil method because it was very dependable.  Over the last 6 months or so I have switched to molten lead at 720 F measured with a thermometer and do it because I don't have to fiddle around getting the oil to burn.   
    Main point is that  almost the only springs that I have had break were the ones in the earliest years which were drawn in molten lead to a colour and altogether I think I have broken only 4 - 6 drill rod springs if that many.  I believe that the ones that broke were not heated high enough and broke because they were brittle.  Theoretically, springs are supposed to break on the tension side and the break is supposed to start at cracks or cuts along the edge much like a piece of glass breaks.  In practice, while I think the above is true for springs that are borderline on being too hard, I also think that for most springs there is a fair bit of leeway.  Partly that is based on the rough appearance of original springs in cheap belgian guns and partly on springs that I have made and had to grind down to make lighter.  I think it is desireable to have a nice looking spring which is polished and bright and I think you do not want to have deep cuts and notches anywhere on the spring but I also think, from experience, that the spring can be a little rough and still be dependable for a long time
     The only material that has not worked for me was a piece of automotive leaf spring.  I drew it to about 720 F because that was as high as my lead pot would go and the spring was springy but not enough and broke.  I suspect this material probably must be drawn to at least 800 F and perhaps higher

cheers Doug

[camerl2009]

     I make 5 or 10 main springs per year and have made at least 50 and probably more total.  I forge & then grind and file them out of drill rod almost exclusively and I assume that to be 1095.   The very first few I drew the temper to just past dark blue (grey) in molten lead.  For at least the past 10 years I used the burning oil method because it was very dependable.  Over the last 6 months or so I have switched to molten lead at 720 F measured with a thermometer and do it because I don't have to fiddle around getting the oil to burn.   
    Main point is that  almost the only springs that I have had break were the ones in the earliest years which were drawn in molten lead to a colour and altogether I think I have broken only 4 - 6 drill rod springs if that many.  I believe that the ones that broke were not heated high enough and broke because they were brittle.  Theoretically, springs are supposed to break on the tension side and the break is supposed to start at cracks or cuts along the edge much like a piece of glass breaks.  In practice, while I think the above is true for springs that are borderline on being too hard, I also think that for most springs there is a fair bit of leeway.  Partly that is based on the rough appearance of original springs in cheap belgian guns and partly on springs that I have made and had to grind down to make lighter.  I think it is desireable to have a nice looking spring which is polished and bright and I think you do not want to have deep cuts and notches anywhere on the spring but I also think, from experience, that the spring can be a little rough and still be dependable for a long time
     The only material that has not worked for me was a piece of automotive leaf spring.  I drew it to about 720 F because that was as high as my lead pot would go and the spring was springy but not enough and broke.  I suspect this material probably must be drawn to at least 800 F and perhaps higher

cheers Doug

if its real drill rod like the stuff used in drill bits and reamers its M2 if it not true high speed drill rod its A2 or D2