Making Springs

Spring making was something most nineteenth century gunsmiths were capable of. As a skill its importance has declined but V-shaped springs are still used in modern firearms, notably the Browning A-5 and many double barrel guns—they are not exclusive to the muzzleloading community. When a modern replacement spring is unavailable or cannot be adapted, a gunsmith may be called upon to make one. It’s not hard and at Trinidad’s NRA Summer School Bench Metal Class I learned an easier method.

Spring Nomenclature Let’s begin with nomenclature; the parts will be capitalized here for clarity. The part with the longer leg and the hooked Claw is the spring’s working part called the Spring. Going towards the "V" is the Bend and the shorter leg is called the Return. The top of the Return sometimes has a Catch which is small hump that serves as the spring’s bearing surface against bolster of the lockplate.

Some Springs have a Locating Pin (English nomenclature) or Stud that is integral to the spring and fits into a hole of the lockplate. This secures the spring in place when it is assembled onto the lockplate. Moving on to materials, students at Trinidad College are provided with 01 spring steel stock that is available from Brownells or any other reputable metal supplier. Dixie Gun Works supplies cold roll annealed 1070-1075 carbon steel.

Cold roll steel has the advantage of having greater strength than hot rolled steel and cold roll’s ability to take high stress makes them especially suitable for springs. Most modern American casted reproduction or percussion locks springs are 6150 steel. Smaller sear springs are cold roll 1095 which was previously tried for casting but per Kit Ravenshear is more difficult to make right.

Regardless of the steel, casted steel grains are not uniformly aligned like rolled or forged steel and while casted springs work, they can break. The metal needs to be shaped as the spring prior to forming. Students begin with a 3 1/2" (88.9 mm) piece of 01 steel that is a half inch (12.7 mm) wide and 1/16" (2.54 mm) thick. The steel is mounted in a vise and the laser cut marks are filed off such that the metal is octagonal in shape.

It is 3/8" (7.62 mm) at the end flaring out for 1 1/2" (38.1 mm) towards the center until it is 1/2" wide for 1/2", and then tapers 1 1/2" down to 3/8" at the other end. Note: This is just a practice spring solely to learn spring making and serves no utilitarian purpose. In the regular bench metal class students make a replacement spring for the CVA Trapper pistol that has shorter Return with a raised Catch that was hand filed into shape.

After shaping the steel to the profile, the Return leaf is tapered down to around 0.050" (1.27 mm) thick. An original Brown Bess’s spring (India pattern) measured 0.127" (3.2258 mm) before the Claw and 0.060 (1.524 mm) at where the Return engages the bolster. On the later P53 Enfield spring it measured 0.046" (1.1684 mm) near the claw and the

Return 0.042 (1.0668 mm) near the Catch. Remember, the ends of both leaves are working surfaces and need thickness for strength. Leaving it thicker allows you to remove metal to adjust the strength. After polishing the surface up to 320, the spring is ready to be bent. On to forming the claw. I recommend shaping the Claw before making the Bend; it’s easier that way.

Since steel is more malleable when heated, torch the area to be worked from medium cherry red to red color (1450° to 1500° For 787.7778°C to 815.5556°C). Note: For a color chart on temperature visit Simply Tool Steel. com/termperature-color-guide. html. We used a rosebud-tipped oxyacetylene torch that allows for more even heating of the entire workpiece. For a forging die, we had apiece of cold roll steel with a U-notch created by a ball end mill. That can also be made with a rat-tail file.

The Claw is made by placing the heated end of the spring over the notch and placing a blunted chisel over the heated metal. Hammering the chisel forces the metal into the notch. Afterward, check for straightness and you may have to reheat the metal and tap it on your anvil to straighten it. The Claw should be filed and polished up to 320 grit. Then draw- He will use the pliers to hold the spring.

Below center: Spring stock being heated on forming jig. file the metal from the Claw to the Bend on both top and bottom sides such that it creates a straight taper. The point where the spring at Claw begins should be 0.050" (1.27 mm) and gradually increasing in thickness to 0.080 (2.032 mm) at the bend. For forming the Vshape, the steel is heated to medium cherry red (1450°For 787.7778°C) where it is to be bent around a forming fixture that merits description.

The instructor Fred Weisenborn made his forming fixture out of cold roll and is basically a T-bar on the bottom (similar to a metal fence post shape) with the forming die welded on top. The T-bar allows for it to be mounted into a vise and acts like a heat sink to protect the vise. Trinidad College has two vises dedicated for projects that require heat treatment in addition to two anvils. The forming die looks like a flaring/arched V against which the deep red spring metal is pressed against with slip jaw pliers.

It is recommended that you use dedicated tools whenever you deal with torches and don’t use expensive tools here when a cheaper import or garage sale bargain tool will suffice. An optional step is to create two small Unotches with around needle file on the inside of where the Bend will be prior to forming. This reduces the metal that will be displaced outward in creating the Bend.

An improvement to the forming die is to make the non-working part behind the Vlonger to accommodate a U-shaped groove created by a ball end mill. This allows the Spring’s long leg to be placed in and struck with a forming die to create the Claw. Don’t make the Vblock and claw forming die too big lest it becomes a heat sink that

Above center: Keep that metal hot! You’re working too hard if you let it cool off. The forming die makes it easy for one person operation. draws too much heat too fast from the workpiece. If you don’t have a Vforming jig, you can place a used hacksaw blade with the teeth ground off down at the bend point and fold the Return over the hacksaw blade and Spring. The hacksaw blade serves to create space between Spring and the Return and prevents them from being crushed together; parting them is a lot of extra work.

Your spring may not be perfectly formed the first time but it can be reheated and placed against the forming die to press the high spots into place. A good spring is neither twisted nor canted and the sides are parallel. Note, if you are making a frizzen spring I suggest making the Return extra long. The extra material is heated, folded over, welded together for thickness and afterward beaten down, filed, shaped, and drilled for the frizzen spring screw.

After bending the spring into the desirable shape, allow it to cool. Then file in the Locating pin/Stud and remove the metal that stands proud above the Locating pin/Stud. Where the spring rests against the lockplate, visually check that it is flush along the contact surface. This prevents torque and unnecessary stress on the locating pin/stud and allows for the spring’s smooth compression and decompression. After filing or grinding down the extra metal, polish the exterior surfaces up to 320 grit.

Polishing makes it easier to see color changes for heat treating. Any scratches that run along the length of the spring needs to be polished out. Scratches near the spring’s V Bend needs to be polished out to 320 grit. The general rule is that there should be no scratches running along the length of the spring. Note, original springs can have decorative file marks on the spring’s side that is away from the lockplate. Instructor Fred Weisenborn provides guidance and insights.

Below center: Instructor heats the forming die preventing the workpiece from cooling off too fast. Hardening and Tempering At this point the spring has been heated inconsistently several times during the forming process. The entire spring is reheated to medium cherry red (1450°For 787.7778°C) to make it consistently heat treated throughout. Afterward it is tempered to remove the hardness so the spring will flex instead of break due to brittleness.

Welding rod was used to suspend the spring such that the "V" is pointed downward. This is because when heated it expands and immersing it leg first may cause the legs to spread. Being denser, dipping the Vin first minimizes this. There are four methods temper the spring and any four will work. First is the oil bath. Heat some motor oil to 600°F (315.5556°C) but never as high as 700° to 725°F (371.1111° to 385° C) because that is its flashpoint and you don’t want a shop fire.

A word of caution, burning motor oil is carcinogenic so if

you choose this method of tempering do it only in a well ventilated area. Let the spring remain immersed for at least ten minutes. An even safer method is placing the spring in an oven pre-heated to 600°F (343.333° C) for ten to fifteen minutes. A third way which is probably more affordable is using the lead pot (also 600° F). The pot must be large enough and have enough lead for the entire spring to be immersed. Leave it in the lead bath for ten to fifteen minutes.

The prettiest way to temper your spring is by immersing in a 600°F (343.333°C) nitre salt bath. Keep an eye on the temperature though as you don’t want the salts Quarter for comparison. to reach 900° F (482.2222° C) since that ruins the salt. Leave it in for ten to fifteen minutes, pull it out and allow it to cool. Our summer school class sequentially used oil, lead, and nitre salts with the workpiece immersed for a minimum of one minute each in the following sequence: oil, lead, and finally nitre blue.

Following the first two immersions the spring was polished with up to 320 grit emery paper before the final immersion. My class only used the lead pot for 15 minutes. This shows there is not just one right way to do things and it’s up to the user to find which works best in their shop Testing Springs by nature can be compressed and uncompressed. The final step is to test whether you have a spring. The workpiece is placed into a vise that is closed until the leaves almost touch at the bend.

If no "ping" (indicating a fracture/ failure) is heard after closing or opening the vise then you’ve made a spring. Do this several times to work the spring. Afterward, oil the spring lightly to protect the finish and it’s ready for installation into the lock or firearm. Good luck! AG